Some of the most common symptoms of nutrient deficiencies are chlorosis, foliage color changes, overall plant stunting and sometimes necrosis. All can be caused by one or more deficiencies.

Signs of damage

Monitor pH Levels – There are lots of things that can cause a hydroponic nutrient solution to drift outside of the ideal range of about 5.6. Usually, if a nutrient solution is left unmonitored for too long, it can start drifting outside of this range because it gets too dense in raw, use nutrients. Other times, it might start becoming too acid or too alkaline when you add new hydroponic nutrients or transfer your plants to a new medium. Since pH levels can change very rapidly, it is important to check your pH level daily. The longer your nutrient solution spends outside of this ideal range, the greater the chance that your flowers or vegetables will suffer a plant deficiency. Use a pharmaceutical grade pH adjustment product designed specifically for hydroponics to make the necessary adjustments. This way you have less of a chance of accidentally over compensating your pH adjustments.  Keep Temperature Levels Stable – Your nutrient solution should be fairly cool to temperate, somewhere in the range of sixty six to seventy one degrees Fahrenheit. You should be particularly aware of this if you happen to live in an unusually warm or cold part of the world. If you feel it is necessary to prevent plant deficiency, take extra steps insulate your grow room against outside elements. You should also avoid placing your reservoir directly on the ground in your grow room, as the floor can be very cool, which can transfer to the reservoir and cause a plant deficiency.

How to prevent

When the temperature of your indoor garden or the nutrient solution falls below 55 degrees Fahrenheit, plants take up less phosphorus than they need. If you've determined that the temperature is not the problem, treat your plants to bone meal, a supplement that's rich in phosphorus.

Treat

main

description

description_sm

description_sm_2

Nutrient deficiency

General symptoms on the solanaceous crops and cucurbits include seed rot and seedling blight which discolors the roots and causes seedlings to topple over. Preemergence and postemergence damping-off are also possible symptoms that may occur.

Avoid overhead watering that can produce surface runoff, and consider slow drip irrigation instead. Hardy Phytophthora blight pathogens will survive in both hot summer and cold winter compost piles. Remove infected plants immediately, bag and dispose of infected debris, and always keep your garden clean.

Crop rotation may reduce the number of pathogens in the soil and, "a minimum of a 3 years crop rotation which alternates with non-host species is recommended to avoid build-up of P. capsici spores." Crops should also avoid conditions that would be conducive to the pathogen by using well drained soils and raised beds. As stated above, "Excess moisture is the single most important component to the initial infection and subsequent spreading of Phytophthora capsici. Overall, a study by K.H. Lamour and M.K. Hausbeck found that "crop rotation and mefenoxam are not likely to provide economic control". Mefenoxem is the active enantiomer contained in the racemic fungicide metalaxyl used to defend against Phytophthora capsici. Sexual recombination provides the genetic diversity to promote resistance towards fungicides in P. capsici. The failure of crop rotation as a means to control P. capsici may also be due to weeds playing the role of an alternative host in the absence of common hosts. According to a study done by the University of Florida, "In Florida, and perhaps elsewhere, weeds may contribute to pathogen survival in the absence of a host crop or when propagules may not readily survive in soil or plant debris." To avoid fruit rot of vegetable crops in the Cucurbitaceae, trellising cucurbit fruits and other ways to keep the fruit off the ground is a way to control secondary inoculants (zoospores) from physically being splashed from the soil onto the fruit. Control of Phytophthora capsici is easier in drier climates with less rainfall such as California. In these areas, it is important to practice placing drip irrigation emitters away from the stems of pepper plants in order to reduce the incidence of crown rot in peppers.

Phytophthora blight

The chlorophyll content of the plant leaves is reduced which results in pale yellow color (chlorosis). Older leaves turn completely yellow. Flowering, fruitings, protein and starch contents are reduced. Reduction in protein results in stunted growth and dormant lateral buds.

Nitrogen deficiency can be prevented in the short term by using grass mowings as a mulch, or foliar feeding with manure, and in the longer term by building up levels of organic matter in the soil.

Fertilizers like ammonium phosphate, calcium ammonium nitrate, urea can be supplied. Foliar spray of urea can be a quick method.

Nitrogen deficiency

When late blight infects stems, everything above the infection site dies. Infected tomato fruits develop rough, leathery spots or dark, water-soaked areas that rot rapidly. Potato tubers bear dark, irregular spots on the surface and reddish-brown spots that extend down into the flesh. Decay continues after harvest.

Fungicides for the control of potato blight are normally only used in a preventative manner, optionally in conjunction with disease forecasting. In susceptible varieties, sometimes fungicide applications may be needed weekly. An early spray is most effective. The choice of fungicide can depend on the nature of local strains of P. infestans. Metalaxyl is a fungicide that was marketed for use against P. infestans, but suffered serious resistance issues when used on its own. In some regions of the world during the 1980s and 1990s, most strains of P. infestans became resistant to metalaxyl, but in subsequent years many populations shifted back to sensitivity. To reduce the occurrence of resistance, it is strongly advised to use single-target fungicides such as metalaxyl along with carbamate compounds. A combination of other compounds are recommended for managing metalaxyl-resistant strains. These include mandipropamid, chlorothalonil, fluazinam, triphenyltin, mancozeb, and others. In the United States, the Environmental Protection Agency has approved oxathiapiprolin for use against late blight.

Ridging is often used to reduce tuber contamination by blight. This normally involves piling soil or mulch around the stems of the potato blight meaning the pathogen has farther to travel to get to the tuber. Another approach is to destroy the canopy around five weeks before harvest, using a contact herbicide or sulfuric acid to burn off the foliage. Eliminating infected foliage reduces the likelihood of tuber infection.

Late blight

Primary symptoms of infection include wilting leaves, blight of young shoots, sunken and darkened areas of stems with possible sap or resin flow, cankering on larger stems and branches, browning of the vascular tissue when bark is scraped away, and canopy dieback.

Avoid planting sites prone to spring frosts and use fertilization, irrigation, and weed control practices that discourage late-season growth and promote early hardening off. Sprays for mummy berry and botrytis may help, particularly during flowering.

Prune and discard all blighted stems and cankered branches from the canopy. For trees with thin bark and dense canopies (e.g. Japanese maple and kousa dogwood), annual sanitation pruning of dead stems, especially on interior canopy branches, can help to avoid disease outbreaks in the future.

Phomopsis cankers and blights

Springtails occasionally feed on plant roots, but the damage is minimal. Problems arise when these pests congregate in moist areas and multiply. Thousands of springtails blanket walls, foundations and patios as their numbers grow. If not stopped outdoors, springtails multiply indoors in damp basements, kitchens and bathrooms — anywhere with sufficient moisture.

It is not difficult to keep this insect at bay. First of all ensure that house plants are always grown in sterile potting compost (this will also help keep away the diseases that the soil can contain).
If there is insufficient drainage, the compost can become waterlogged, so, next, always ‘crock’ a pot with a layer of grit or clay pellets before adding compost. If the compost to be used is too compact, coarse sand or perlite can be added to make it more free-draining.
If you find it difficult to assess when to water use a moisture meter, a self-watering cone or a container with a reservoir. In the latter cases, the compost takes up water gradually as it dries out, ensuring an even supply.

1 First of all, stop watering the plant and allow it almost to dry Out before re-watering. ‘This may be enough to eradicate these pests. It not, then you will need to use a chemical.
2 Use a suitable chemical, in granule form or diluted with water, to soak the potting mixture.
3 Insecticides containing diazmon, lindanc, malathion, pyrethrum or resmethrin are suitable. Make sure that due ingredients of an insecticide are listed on its label. One application of the chemical should be enough but repeat the application after 8 days to ensure eradicating ideal conditions for springtails.
4 If your plants are infested with Springtails, you will know as soon as you water them, as these tiny insects will start jumping about on top of the potting mixture.
5 Springtails will thrive in waterlogged soil so always water very carefully and ensure that the plant has good drainage.

Springtails

Fungus gnat damage will appear similar to that of any other root-related issue, such as root rot. Lower leaves may turn yellow and drop, and the plant’s growth may slow down or stop completely. In particularly bad cases, wilting of the entire plant could occur, followed by the death of the plant if roots are extremely damaged. 
In small numbers, fungus gnats are more of an annoyance than anything. In fact, the adult gnats don’t actively harm plants nor people. If their population gets out of hand, however, the larvae may start feeding on plant roots, causing notable damage. This is especially bad for young plants, such as seedlings, which have only a few delicate roots. Fungus gnats are also capable of spreading the plant pathogen that causes damping off and the eventual death of seedlings.

1. Keep soil dry: Fungus gnats seek out moist soil, so allowing your houseplants to dry out a bit between waterings can slow down or stop an infestation. Let the top inch or two of soil dry out before watering again, and try to go as long as possible between waterings. Gnats may be deterred from laying their eggs if the soil is dry on the surface.
2. Mosquito dunks (with beneficial bacteria): Mosquito dunks are used to keep mosquito larvae from populating fountains, animal troughs, fish ponds, and other small bodies of water. The product consists of a dry pellet containing a type of bacteria called Bacillus thuringiensis subspecies isrealensis. This beneficial bacteria infects and kills the larvae of flying insects, including mosquitoes, fruit flies, and fungus gnats.
To use mosquito dunks: Fill up a gallon jug (or watering can) with clean water and toss in a mosquito dunk. It’s a good idea to break up the dunk a bit before placing it in the water, or you can wait for it to soften before breaking it apart. Let the dunk soak in the water for as long as possible (at least overnight), then remove it from the water (the dunk can be reused) and use this water for fungus gnat–infested plants. The bacteria will have leeched into the water and will now infect and kill any larvae that come into contact with it in the soil. Repeat this process every time you water your plants for at least a few months.
3. Cover drainage holes: Though gnats typically remain near the tops of pots, they may find their way to the drainage holes on the underside of a pot and start laying eggs there, too. If this happens, cover the drainage holes with a piece of synthetic fabric to prevent the gnats from getting in or out of the hole, but to also let water pass through freely. Attach with tape or rubber bands.

Getting rid of fungus gnats is all about consistency. Catching the adults is fairly easy, but because the adult population comes in cycles, you need to make sure that your traps are refreshed regularly. For the best results, use a combination of the traps :
1. Sticky cards traps: These traps consist of a yellow note card covered in a sticky adhesive. They are most effective when cut into small squares and placed directly on top of the soil or attached to skewers just above the soil. Adult gnats will fly or crawl onto the card and become trapped. Fungus gnats are attracted to the color yellow, so use the yellow sticky cards rather than the blue ones. 
2. Cider-vinegar traps: Simple and effective, cider-vinegar traps consist of a shallow container with a small amount of apple cider vinegar, water, and liquid dish soap.
To make a cider-vinegar trap: Find a shallow container—a tuna can is perfect—and fill it with equal parts water and apple cider vinegar. (The liquid should be at least ¼-inch deep.) Put a few drops of liquid dish soap into the mixture and stir gently. Place the trap near the base of the affected plant or, ideally, inside the pot on top of the soil. Check it every few days to refresh with new vinegar and water.
3.Flypaper: Flypaper ribbons, such as those hung in horse barns to catch outdoor flies, can also be used to catch fungus gnats. However, these traps are usually overkill for gnats and can easily get stuck to things you don’t want them to stick to, such as furniture, hair, plants, and so on.

Fungus Gnats

Raised yellowish-orange, powdery pustules on the surface of infected foliage. Significant foliar dieback occurs on especially susceptible cultivars.

As with other fungus, daylily rust thrives in moisture. Use soaker hoses rather than overhead watering systems and water in the morning rather than late in the day or at night. This will cut down on the amount of time that the leaves remain wet.

Do not move or transport infected plant material. Carefully inspect incoming plant material for signs of rust. Fungicide applications are needed for disease management, especially on susceptible cultivars. Contact your local extension office for information on ratings of cultivar susceptibility and current fungicide control recommendations.

Daylily rust

Whiteflies tend to prefer to feed on new growth, so check around any newly unfurled leaves first.
Check the undersides of leaves—especially around the veins—for white insects, even if they aren’t immediately visible, and feel leaf surfaces for sticky honeydew. If the whiteflies are feeding, they’ll suddenly all fly off the leaves in a swarm, so it’s very obvious.
You may also find eggs laid on the undersides of leaves. This is the beginning of a new generation! When the eggs hatch, the larvae will look like teeny white ovals without legs; they don’t move but they immediately start sucking the plant juice. This is why gardeners often miss whiteflies until it’s too late. Adult females can produce up to 400 eggs, which hatch in about one week to a month after laying. They are usually laid in a circular pattern. Eggs are pale yellow when newly laid and brown when about to hatch.

1 Your first line of defense should be inspecting all plants for pests before you bring them home, as well as keeping any new additions away from the rest of your plants for a period of time. This will allow you to identify and curtail any pest or disease issues that appear.
2 Keeping natural predators around will prevent whiteflies from ever exploding in population. For this reason, avoid using insecticides. Ladybugs, spiders, green lacewing larvae, and dragonflies are a few of many beneficial insects that can control a whitefly population. Hummingbirds are another natural predator. Try creating a habitat that will attract dragonflies and damselflies (which also helpfully eat mosquitoes) or beautiful hummingbirds.
3 When it comes to whiteflies, avoid chemical insecticides; they’re usually resistant and all you end up doing is killing the beneficial insects—their natural predators—and the insects that pollinate the garden for a better harvest!
4 Mulch early in the season with aluminum reflective mulch, especially around tomatoes and peppers. The reflective mulch makes it challenging for whiteflies to find their preferred host plants. 
5 Set out yellow index cards coated with petroleum jelly to monitor whiteflies, especially when it comes to tomatoes, peppers, sweet potatoes, or cabbage crops. A half-and-half mixture of petroleum jelly and dish soap, spread over small boards painted bright yellow, is sticky enough to catch little whiteflies, too. To whiteflies, the color yellow looks like a mass of new foliage. The bugs are attracted to the cards, get stuck in the jelly, and die.

To control whiteflies, there are various solutions and traps that you can use. The biggest tip is: start early! In the mornings and evenings, as you wander the garden or tend to your houseplants, check the back of the leaves for eggs or notice when little bugs “fly away” as you approach your plants.
- Always start with blasting whiteflies (as with aphids and many other insect pests) with your watering hose or a spray bottle. This will cause them to scatter and will dislodge nymphs and eggs to some extent.
- Consider spraying your plants’ leaves with an insecticidal soap, following the directions on the packaging. Be sure to spray the undersides of leaves, too. Follow up 2 or 3 times, as necessary. 
Spray plants in the evening when temperatures are cooler, as mid-day heat may cause an adverse reaction in your plant. Plus, spraying in the evening allows you to avoid accidentally spraying any pollinators or beneficial insects.
- According to the National Gardening Association, the following simple homemade mixture should be helpful to control and deter whiteflies: Use a mix of dish soap and water. A good squirt of soap to a gallon of water should work. As mentioned above, only spray in cooler temperatures; late in the day is best. The NGA mixture is a pretty benign combination, and whiteflies are nearly impossible to get rid of, so it’s best to try more preventative tactics first, as mentioned below.
- If all else fails and your whitefly population is persistent, you can (carefully) use a handheld vacuum every few days to remove them from your plants. This gets rid of both nymphs and adults. Just be sure NOT to empty your vacuum into a trash can inside your home afterward

Whiteflies

In the fruits, black or brown lesions (e.g., on pods, scab, and pitting) are common. Infection on the inflorescence produces blight, necrosis, and lesions with flecks and streaks. Infected leaves produce abnormal colors and patterns with dark, necrotic, angular, or irregular areas.

Plant resistant plants, or buy healthy transplants. Plant your plants in well-drained soil.  Water your plants with a drip sprinkler, as opposed to an overhead sprinkler.. Keep ripening fruits from touching the soil. Remember to rotate your plants every 2 to 3 years.

The best control products were Daconil Ultrex (chlorothalonil), Pageant (pyraclostrobin and boscalid) and Spectro 90WDG (chlorothalonil and thiophanate methyl). In addition, mancozeb (i.e., Dithane and Pentathlon) or copper were also very effective when used preventively.

Colletotrichum

Rust symptoms first appear on the upper and/or lower surfaces of leaves as small yellow or white slightly raised spots.

Remove all infected parts and destroy them. For bramble fruits, remove and destroy all the infected plants and replant the area with resistant varieties. Clean away all debris in between plants to prevent rust from spreading. Avoid splashing water onto the leaves, as this can help spread rust.

Use a mild bleach solution, and rinse and dry them thoroughly before putting them away. Rake up and remove fallen or dead leaves and other plant debris. Some gardeners compost vegetation that show signs of rust, expecting the compost pile to heat up enough to kill the spores.

Rust

Leaf spots will begin as very small, yellow, brown or black spots that enlarge in size. The spot usually turns gray with a black outline. Lesions on the petiole and rachis are similar. Symptoms may occur on multiple leaves at once, especially on juvenile palms.

Fungicides are used to prevent further spread of the disease by protecting leaf tissue that has not been infected by the fungal pathogen. In the nursery situation, prune severely diseased leaves prior to fungicide application.

In rare cases of severe infection and where the size and value of plants make it practicable, applications of fungicides may be helpful.

Pestalotiopsis leaf spot

Most of the time, this pest is identified by the leaf miner damage. Frequently, it appears as yellow, squiggly lines in the leaves. This is where the leaf miner larva have literally bored their way through the leaf. Leaf miner damage can also appear as spots or blotches.

Pick off and destroy badly infested leaves in small gardens. The more healthy the plant, the less chance that leafminers will hurt it. Maintain plant health with organic fertilizers and proper watering to allow plants to outgrow and tolerate pest damage. Keep your soil alive by using compost and other soil amendments.

The most common method to rid plants of leaf miners is to spray general pesticide on the infected plants. The trick to this method of how to kill leaf miners is to spray at right time. If you spray too early or too late, the pesticide will not reach the leaf miner larva and will not kill the leaf miner flies.

Leaf miners

Wilted, downward-hanging foliage is often the first obvious symptom of Armillaria root rot. Other symptoms include foliage yellowing, leaf drop, and dieback of upper limbs. During the rainy fall and winter, groups of short-lived mushrooms often grow around the base of Armillaria-infected trees.

Cultural practices can also be effective for preventing the spread of Armillaria. High temperatures interfere with the progression of this disease; if soil temperatures reach 79 °F (26 °C), then the growth of Armillaria in the soil will be limited. Using collar excavation to expose primary roots directly below the crown to the continuous cycle of solar heating and air may reduce the colonization from Armillaria in trees that are already infected. This is called root collar excavation (RCE), and while it has been applied to citrus orchards and grapevines, this method has high labor costs and involvement due to the difficulty of carefully exposing these primary roots.

Sadly, there is no absolute treatment for Armillaria root rot. The disease can be managed by the consistent removal of dead trees and infected stumps. Armillaria requires consistent moisture to survive, and in citrus groves, excavation around the root crown has been an effective deterrent but not an ultimate cure.

Armillaria root rot

Common, Persian, Chinese, and Japanese lilac leaves develop round to irregularly shaped brown spots with yellow halos. These spots enlarge and blight entire leaves. Succulent twigs are girdled, killed, and turn black.

1. Exclusion or eradication of the pathogen (quarantine and use of pathogen-tested seeds and propagated materials)
2. Use of clean transplants.
3. Monitor crops regularly and use predictive models.
4. Reduce the pathogen levels by crop rotation.
5. Remove weeds and incorporate crop residues that can host the disease.

The most common strategy for controlling diseases caused by Pseudomonas syringae is, as it has been for more than 5 decades, to spray bactericides. These mainly include a variety of copper compounds or other heavy metals, with or without various combinations of fungicides or other pest-control chemicals.

Pseudomonas

Leaf curl and distortion. Leaf yellowing or stippling. Necrotic leaf spots. White sporulation of the pathogen on lower leaf surface. Defoliation.

Use hygiene measures. Start clean, remove crop residues and prevent splashing water.

One way to control downy mildew is to eliminate moisture and humidity around the impacted plants. Watering from below, such as with a drip system, and improve air circulation through selective pruning. In enclosed environments, like in the house or in a greenhouse, reducing the humidity will help as well.

Peronosporea

Plants with severe rust infection may appear stunted, chlorotic (yellowed), or may display signs of infection such as rust fruiting bodies. Rust fungi grow intracellularly, and make spore-producing fruiting bodies within or, more often, on the surfaces of affected plant parts.

Planting resistant crops is the ideal form of disease prevention, however, mutations can give rise to new strains of fungi that can overcome plant resistance. Although the disease cannot be stopped by removal of the alternate host, the life cycle is disrupted and the rate of mutation is decreased because of reduced genetic recombination. This allows resistance bred crops to remain effective for a longer period of time.

Macrocyclic Disease: Developing a management plan for this type of disease depends largely on whether the repeating stage (urediniospores) occur on the economically important host plant or the alternate host. For example, the repeating stage in white pine blister rust disease does not occur on white pines but on the alternate host, Ribes spp. During August and September Ribes spp. give rise to teliospores which infect white pines. Removal of the alternate host disrupts the life cycle of the rust fungi Cronartium ribicola, preventing the formation of basidiospores which infect the primary host. Although spores from white pines cannot infect other white pines, survival spores may overwinter on infected pines and reinfect Ribes spp. the following season. Infected tissue is removed from white pines and strict quarantines of Ribes spp. are maintained in high risk areas.

Pucciniales

The black spots are circular with a perforated edge, and reach a diameter of 14 mm (1⁄2 inch). Badly affected plants, however, will not show the circular patterning, as they combine to cause a large, black mass. The common treatment of the disease is to remove the affected leaves and spray with antifungal solutions. Some stems of the roses may become affected if untreated, and will cause progressive weakening of the rose.

Keep the foliage as dry as possible, since the spores need a wet surface in order to germinate. Avoid overhead watering, or water early in the day so the foliage has time to dry before nightfall. Improve the air circulation around your roses by spacing them properly and pruning them regularly.

Removing infected leaves from the plant and fallen leaves from the ground will slow the spread of the infection, as does avoiding wetting the leaves of plants during watering. An infected plant can be removed from the area, which will slow the spread of infection to other plants, but this often is not desirable. Fungicides, such as mancozeb, chlorothalonil, flutriafol, penconazole, or a copper-based product, applied upon new leaf emergence or first appearance of black spot, can be used to control the disease. If a more natural and nontoxic approach is desired, diluted neem oil is effective both against black spot and as an insecticide against aphids, or cows milk diluted 1:3 with water is effective if sprayed on to the leaves. It is usually necessary to repeat the spraying at seven- to 10-day intervals throughout the warmest part of the growing season, as the fungus is most active at temperatures from 24 to 32 °C (75 to 90 °F).

Black spot

Stems will be leggy or stretched out. Leaves turn yellow. Leaves are too small.

Arrange the light sources so that the plant receives the required number of photons.

Make sure your plant gets not too much/not too little light.

Light-related issue

The symptoms in the upper parts of the plants cannot be recognized in early stages of root infection.

Diagnosis of this disease is difficult and laborious because infected roots in the soil can only be detected by digging up the soil and observing the roots by eye, trapping mycelia around the infected roots by the bait twig method

Sordariomycetes

Symptoms of bacterial infection in plants are much like the symptoms in fungal plant disease. They include leaf spots, blights, wilts, scabs, cankers and soft rots of roots, storage organs and fruit, and overgrowth. Bacterial spots: the most common symptom of bacterial disease is leaf spots.

The best way to prevent fungi from attacking your plants is to buy disease resistant varieties whenever possible. Other ways include minimizing the amount of water contacting foliage. Water at the soil level and early in the day. This allows foliage to dry out quickly, should it become wet.

Antibiotics: streptomycin and/or oxytetracycline may also help kill or suppress plant pathogenic bacteria prior to infection and reduce spread of the disease, but they will not cure plants that are already diseased. Antibiotics are also used to treat diseases caused by fastidious vascular bacteria.

Bacteria

The earliest symptoms of rose rosette disease include a red pigmentation of the underside of leaf veins followed by sharply increased growth of vegetative shoots, which are typically more succulent than normal and colored in various shades of red. Leaves often become deformed, crinkled, and brittle with yellow mosaics and red pigmentation. As the disease progresses, leaves become very small, petioles are shortened, and most lateral buds grow, producing short, intensely red shoots. The disease causes the plant to be exceptionally susceptible to freeze damage. Symptoms on cultivated roses are typically less severe than on multiflora rose. Cultivated roses show symptoms of thickened, succulent stems and a proliferation of thorns. Symptoms can mimic some forms of herbicide damage.

Prune your roses in late winter or early spring. Do not use leaf blowers around your roses. Protect roses from prevailing winds with walls or other plants. Give your roses plenty of space. Control multiflora rose in your area.

1. Remove ornamental roses with symptoms. The entire plant including the roots should be removed and destroyed by burning or placing in a plastic bag. Care must be taken when working with diseased plants as you can facilitate spread of the mites that spreads the disease. Bag the plant before removal, cut it at ground level and then dig out the plant’s roots. Soil need not be removed. Clean tools and put on fresh clothing before moving to a disease-free plant or area. 2. Plant ornamental roses as far away as possible from known stands of multiflora rose. The general recommendation is maintain at least 300 feet between your roses and any stands of multiflora rose. Even greater distance is preferred especially if they are upwind of your desirable rose plants. 3. Control the disease by controlling the mite. Start mite control early by pruning your roses hard in late winter (back by 2/3) to remove as many overwintering mites as possible and then spray with horticultural oil to kill any remaining mites. Organic pesticides such as horticultural oils and insecticidal soap are recommended over other pesticides as these organic pesticides are less harmful to natural predators that feed on the problem mites. Apply weekly  during the months of June and July paying particular attention to the new growing tips where the mites will congregate. Refrain from using leaf blowers around roses as they can spread mites. 4. Help to isolate your roses. Do not plant roses too close together. With extra space between the plants mite movement can be reduced. Also, consider interplanting roses with other ornamental plants. 5. Using rose rosette disease as an IPM strategy. The multiflora rose is an exotic invasive species that is responsible for the degradation of millions of acres of farmland and recreational areas. Using the disease to control this invasive weed can cut costs and be considered environmentally friendly for reducing the amount of synthetic chemicals used. However, the disease also affects cultivated roses. One should be extremely cautious and good neighbor-minded when it comes to rose rosette disease.

Rose rosette disease

If the stem is mushy or brittle, check the roots for the same conditions. The roots, too, should be pliable but firm. If both the stems and roots are brittle or mushy, the plant is dead and you will simply need to start over.

Repot your plant. Use a high-quality indoor plant potting mix to revitalise your plant, and choose a pot that's wider than the last one. ... Trim your plant. If there's damage to the roots, trim back the leaves. Move your plant.  Water your plant.  Feed your plant.  Wipe your plant.

Gently remove the plant from its container. If you see more roots than soil, or roots coiling around the inside of the pot, it is time for a bigger container. Over time, most plants outgrow their pots. Sometimes, all it takes to revive a dying plant is a little repotting.

Dead plant

Plants' roots are not typically visible as they are below the surface of the soil, so the symptoms of root rot are often apparent only when the disease is advanced. Roots of plants affected by root rot may turn from firm and white to black/brown and soft. Affected roots may also fall off the plant when touched. The leaves of affected plants may also wilt, become small or discolored.Affected plants may also look stunted due to poor growth, develop cankers or ooze sap. Prolonged root rot may lead to death of the plant. In extreme cases, plants affected by root rot may die within 10 days. Root rot is usually[citation needed] lethal although it is treatable. An affected plant will not normally survive, but may potentially be propagated.

To prevent recurrence and progression of root rot, it is recommended to water plants only when the soil becomes dry, and to plant the plant in a well-drained pot. It is recommended that pots used for diseased plants should be sterilized with bleach to kill potential spores. This allows the plant to drain properly and prevents fungal spores affecting the plant. It is recommended to keep the soil around the plant as dry as possible and to pry back the soil to allow proper aeration.

The most effective treatment for root rot is prevention such as destruction of affected plants. It is recommended that, in localised cases of root rot, the affected plant simply be destroyed and the surrounding soil replaced. Treatment options depend on the extent of the rot. To treat root rot, is recommended to replant the affected plant in fresh soil with good drainage to avoid standing water. It is also recommended to gently wash diseased roots and remove all brown, soft parts of the roots with a sterilized pair of scissors or a tool such as a pulaski for larger roots. Rapid treatment and replanting of root rot is imperative to stop the disease spreading to the rest of the affected plant or to other plants and to allow plants to form new roots. Chemical treatments, such as fungicides, chloropicrin and methyl bromide may also be used to limit progression of the disease but must be specific to the responsible pathogen. Some sources claim that cinnamon powder is an effective treatment for reducing spread of root rot, when applied to exposed tissue after removal of diseased tissue. Cinnamon is also claimed to act as a potential fungicide.

Root rot

Lower leaves are yellow. Plant looks wilted Roots will be rotting or stunted. No new growth. Young leaves will turn brown. Soil will appear green (which is algae)

Rainwater harvesting and recycled wastewater also allow to reduce scarcity and ease pressures on groundwater and other natural water bodies. Groundwater recharge, that allows water moving from surface water to groundwater, is a well-known process to prevent water scarcity.

The provision of water treatment chemicals ensures the provision of safe water.

Water-related issue

Usually the first sign of thrip damage is faded or dirty looking leaves. The leaves will start by turning white or grayish in color, then eventually brown as the damaged areas start to die.
Though it’s possible for thrips to kill a houseplant, it’s rare. Mature, healthy houseplants can handle a pretty heavy infestation. The biggest threat is to small or weak houseplants.
However, not only is a thrip infestation gross, they make your indoor plants look terrible, and heavy damage can stunt their growth. Other common symptoms include:
- Brown stripes on the leaves
- Faded, splotchy, pale-colored leaves
- Parts of the leaves are dying
- Flower buds are malformed, dropping, or won’t open
- Leaves start dropping unexpectedly
- New growth is deformed

Thrips can be difficult to get rid of. So, once you finally win the battle, you want to prevent them from ever coming back!
The good news is that there are a few easy ways to prevent thrips from infesting your houseplants…
- Monitor them on a regular basis for the first signs of an infestation
- Debug all of your plants before bringing them back inside for the winter
- Keep anything that you bring in from your garden (cut flowers, veggies…etc) far away from your houseplants
- Inspect all new houseplants before bringing them home, then quarantine them for a few weeks afterward

The first thing you should do as soon as you spot thrips on a houseplant is to quarantine the infested plant immediately. Then check all of the surrounding houseplants for signs of thrips, and isolate any others you may find.Make sure that you begin treating the infestation right away. Also, to help prevent thrips from spreading, always wash your hands after handling an infested houseplant.
RINSE THE LEAVES
If you can, take your houseplant outside, and rinse the leaves with the hose. That will remove many of the bugs, and quickly knock down their population.You could rinse the leaves in the sink or shower instead, and that will work too. Be sure to use tepid water, and take care not to overwater your houseplant in the process.
INSECTICIDAL SOAP
Soap kills thrips on contact, and will help to give you the upper hand. You can use a pre-mixed organic insecticidal soap, or make your own using 1 tsp mild liquid soap to 1 liter of water.Be sure to spray it directly on the infested leaves to kill the bugs. Insecticidal soap doesn’t have any kind of residual effect, so it’s important to treat them often in order to completely get rid of thrips.
WASH YOUR HOUSEPLANT
You could also try washing the leaves with diluted mild liquid soap, and rinse it off with water. This will kill thrips as well, and help to quickly get the population under control.Make sure you wash the undersides of leaves too, that’s where thrips like to hide. But before washing all of the leaves, it’s best to test the soap on a few first, to make sure it doesn’t damage your houseplant.
NEEM OIL 
It’s a naturally occurring insecticide, and also has a residual effect that will help to deter future infestations.Spray a neem oil solution directly on the leaves and stems. This will kill some of the bugs on contact, and others will die when they feed on the neem oil covered leaves. Either a pre-mixed horticultural oil or a hot pepper wax spray can also be very effective to get rid of thrips on houseplants.
STICKY TRAPS 
Since adult thrips are able to fly, sticky traps can work very well to capture them. Place either yellow or blue sticky traps near the infested houseplant to attract them.

Houseplant Thrips

The pathogen causes angular chlorotic lesions on the foliage. These lesions appear angular because they are bound by leaf veins. During humid conditions, inspection of the underside of the leaf reveals gray-brown to purplish-black fungal growth. This downy material is the sporulation of the pathogen. Magnification of the sporulation reveals the acutely and dichotomously branched sporangiophores bearing lemon-shaped sporangia. Eventually, leaves will turn necrotic and curl upwards. The disease is sometimes called wildfire because of how rapidly it progresses, as if the crop were burned by fire. Symptoms on watermelon and cantaloupe are different from on other cucurbits; leaf spots are typically not angular and turn brown to black in color. Often, an exaggerated upward leaf-curling will occur. Regardless of which cucurbit is involved, only the leaves are infected, not fruit, flowers, stems or roots. Disease of the leaves results in three major effects: 1. reduced yields, 2. a greater proportion of misshapen fruit, especially in cucumber, and 3. sunscalded fruit, due to increased exposure to direct sunlight, especially in watermelon and winter squash.

Early detection of downy mildew and immediate or preventative fungicide application is imperative for the control of this disease. A forecasting system exists to assist growers in timing their fungicide applications for maximum benefit. The system tracks outbreaks of the disease and provides a forecast or risk assessment for future outbreaks.

Resistant cultivars - Host resistance is an important tool in disease control and should be used whenever possible. Cultivars resistant to downy mildew have been developed for cucumber and cantaloupe and to a lesser extent for squash and pumpkin. Although cucumber downy mildew has been severe on resistant cultivars, these cultivars are more effective than susceptible cultivars in delaying infection. Chemical control - Chemical control is highly recommended because downy mildew is an aggressive and destructive disease and satisfactory control without the use of fungicides is unlikely. Both protectant and systemic products should be applied. Fungicides are most effective when applied prior to infection and reapplied at 5- to 7-day intervals. The following products have proven to be the most effective fungicides in cucumber downy mildew control in North Carolina trials conducted annually from 2004 to 2008: Presidio (fluopicolide, Valent), Ranman (cyazofamid, FMC), Previcur Flex (propamocarb, Bayer), Curzate (cymoxanil, DuPont), Tanos (famoxadone and cymoxanil, DuPont), and Gavel (zoxamide and mancozeb, Dow AgroSciences). These products should be applied in a program to prevent pathogen resistance, that is, rotated with fungicides of a different mode of action. Protectant fungicides such as chlorothalonil and mancozeb should be used as mixing partners. Вiological control - Although many biological control products have been evaluated for their ability to control downy mildew, none have proven effective and are not recommended for use.

Cucurbit downy mildew

Leaf spots start as small brown spots, often with a yellow halo, and grow into irregular brown spots (up to 3/4"). Leaf spots sometimes develop a target-like pattern of rings. Severely infected leaves turn brown, curl upward, wither and die.

Avoid overhead watering to limit leaf wetness, and allow enough space at planting time for good air circulation and ample sun penetration. Keep your garden free of fallen leaves all season, and especially thorough at fall cleanup time.

Treatment for Alternaria requires fungicide to be sprayed directly on infected plants, as well as improvements in sanitation and crop rotation to prevent future outbreaks. Organic gardeners are limited to sprays of captan or copper fungicides, making control much more challenging.

Alternaria blight

The most common sign of anthracnose is the spots that appear on new leaves. These spots are irregularly shaped and are tan, brown, or black in color. In some trees, these spots appear all over the leaves and on others they may appear along the leaf veins.

Plant resistant plants, or buy healthy transplants. Plant your plants in well-drained soil.

Anthracnose diseases typically do not kill the host directly, however, repeated infections on woody plants over a period of years may lead to a general decline and dieback. Control of anthracnose diseases becomes important when the host is economically important and the goal is production for fruit or lumber. Otherwise, anthracnose diseases generally go unattended and raise concern only when premature leaf drop calls attention to the situation.

Anthracnose

Alternaria symptoms once infection begins include small, dark, circular spots that regularly reach ½ inch (1 cm.) in diameter.

Treatment for Alternaria requires fungicide to be sprayed directly on infected plants, as well as improvements in sanitation and crop rotation to prevent future outbreaks. Organic gardeners are limited to sprays of captan or copper fungicides, making control much more challenging. Conventional gardeners can use chlorothanil, fludioxinil, imazalil, iprodine, maneb, mancozeb, or thiram on plants listed on the label of their chemical of choice, but should still strive for prevention in areas with known Alternaria pathogens.

Alternaria

Black mold is characterized by obvious lesions that appear on the surface of ripe fruit. Lesions are light to dark brown and vary from small flecks affecting only epidermal tissue to large, more or less circular, sunken lesions with decay extending into the carpel wall and often into the seed locule. During warm, humid weather the fungus may sporulate to form a black, velvetlike layer on the surface of the sunken lesions.

Select resistant varieties of plants/crops that are less susceptible to important pathogens. Pathogens reproduce at higher rates on susceptible varieties compared with resistant or partially resistant varieties. Cultural practices grapeCapitalize on cultural practices to reduce the pathogen population or create conditions less favorable for the pathogen to develop. When fewer non-chemical control methods (such as sanitation) are used, resistance is more likely to develop, or will develop more rapidly. Monitor and maintain agronomic factors such as soil moisture and crop nutrition, and manage other pests, to avoid crop stress throughout the season.Inadequate or excessive fertilization with nitrogen may increase disease incidence in some crops.  For example, early blight of potato and tomato and dollar spot of turfgrass are favored by nitrogen deficiency.  Alternatively, the severity of spring dead spot of bermudagrass and some foliar diseases of wheat is increased with intensive nitrogen fertilization. Excessive irrigation or frequent irrigation with small amounts of water increases the incidence of many diseases by promoting spread of the pathogen and extending periods of leaf wetness, and high soil moisture. Rotate crops to allow greater flexibility in choosing different tillage practices and/or the use of fungicides with different MOAs. Be aware that applying a fungicide unnecessarily to a crop in one year in the absence of fungus could result in undesirable effects on pathogens of rotational crops. NOTE: It is possible to rotate different crops between years and, yet, still use the same fungicide MOA to control the same disease. When one crop can serve as a source of inoculum for a subsequent crop, the alternation scheme among at-risk fungicides should be continued between successive crops such that the first at-risk fungicide applied to a crop belongs to a different group than the last at-risk fungicide applied to the previous crop.Be aware that resistant plant pathogens can spread from nearby fields, highways, railroads, or utility rights-of-way areas near your farm or treated site. Local and regional cooperation in resistance management is essential. Participate in Extension programs that conduct area-wide monitoring for the presence of disease pathogens and potential resistance development. Submit reports of fungicide control failures so that the possibility of resistance can be monitored and evaluated.

Fungicides are pesticides that kill or prevent the growth of fungi and their spores. They can be used to control fungi that damage plants, including rusts, mildews and blights. They might also be used to control mold and mildew in other settings.

Alternaria black molds and stem cankers

Symptoms vary across plant organs and tissues. B. cinerea is a soft rot that will have a collapsed and water soaked appearance on soft fruit and leaves. Brown lesions may develop slowly on undeveloped fruit. Twigs infected with gray mold will die back. Blossoms will cause fruit drop and injury, such as ridging on developing and mature fruit. Symptoms are visible at wound sites where the fungus begins to rot the plant. Gray masses with a velvety appearance are conidia on the plant tissues are a sign of plant pathogen. These conidia are asexual spores that will continue to infect the plant and surrounding hosts throughout the growing season making this a polycyclic disease. Plants can produce localized lesions when a pathogen attacks. An oxidative burst causes hypersensitive cell death called a hypersensitive response (HR). This soft rot can trigger HR to assist in colonization. Botrytis cinerea, as a necrotrophic pathogen, exploits the dead tissue for its pathogenicity or its ability to cause disease. Susceptible plants cannot use the HR to protect against Botrytis cinerea.

The best way to prevent gray mold is to space out plants so they have room to dry out after rain or watering. Remove infected flowers, leaves and stems. Infected plant parts should be buried or composted. Many flowering plants can recover from gray mold when warm, dry conditions return.

Prune or stake plants to improve air circulation between plants. · If growing indoors use a small clip-on fan to improve air flow.

Gray mold

Plant stunting and severe curling of leaves occur when the leafhopper Empoasca fabae punctures the undersurfaces of leaves and veins of bush beans and inhibits growth. This leafhopper also feeds on alfalfa and causes leaves to turn yellow and drop off.

Try to avoid moisture or humidity relationships as they affect the habitats of homopterans.

When controlling thrips, you can prune and get rid of any injured areas on the plant. Regular pruning helps get rid of thrips. Thrips on flowers can be eliminated as soon as you see signs of damage by using a mild insecticide like insecticidal soap or neem oil, or by pruning the flowers.

Homoptera

Hosta virus X does not kill the plants infected, but Hostas that have been infected do show a variety of other symptoms, such as: Ink-bleed, which makes the plant look discolored in certain spots, and this effect is generally centered on a vein. An example of this is shown in the photo in this article. Desiccation or Collapsed tissue, which can be signs of heavier infection, makes the plant look as if it is dried out. Mottling, which makes the plant appear blotchy. This is not always a symptom of HVX, and could be from another virus, but it should always be treated as an infected plant regardless. A Hosta may no longer express symptoms of the virus when it grows back in the Spring, even though it may have shown symptoms in a previous year. Nonetheless, the plant should still be considered infected with HVX.

The only way to eliminate the disease is to destroy infected plants (and any associated plant debris) by burning (where allowed by local ordinance) or landfilling. DO NOT compost hostas with HVX.

Once a Hosta plant is infected, it will be infected for the rest of its life. Any plant suspected of being infected should be burned if it is legal to do so. If it is not, then it should be tossed in the garbage, but infected Hosta plants should never be composted. If any plant in a batch shows symptoms, the entire batch should be considered infected and be destroyed. Once a plant has been removed, the spot occupied by the Hosta should be left empty for a long time to prevent the spread of the virus to a plant that replaces it. The virus primarily spreads through infected sap, so cutting multiple plants with the same tool can spread the virus. Animals that eat the plants may also spread the virus through sap by eating from an infected plant and then eating from an uninfected plant.

Hosta virus x

- Black or dark brown, superficial fungal growth on the aerial parts of plants, particularly the upper leaf surfaces
- The amount of growth can vary from a fine soot-like or powdery deposit, to a thick sheet of growth that may crack or peel away from the leaf surface during dry conditions
- The growth can sometimes be washed away, leaving a healthy-looking leaf surface beneath
- Sap-sucking pests such as aphids, scale insects, mealybugs or whiteflies can often be found on the plant, above the point where the sooty mould is growing
- In some cases these insects may occur on plants that overhang those affected with sooty mould
- Ants may also be seen in association with the sap-sucking pests
- Leaves, stems, fruit, etc. where the sooty moulds are growing are contaminated with sticky honeydew

It isn’t really possible to preventively treat against sooty mold, and when it appears it is immediately recognizable.
There are a few things to do that can reduce the likeliness that this disease would appear.
- Ensure your plant has sufficient nutrients and is well watered. A plant weakened by poor soil or lack of water is a vulnerable plant.
- Increase the diversity of plants and flowers in your garden, it is the best way to protect them naturally from their predators.

Sooty mold grows on the honeydew dropped by many sap-feeding insects (most commonly aphids, scale and whiteflies). The honeydew is a sugary liquid that the insects excrete as waste. Sooty mold in itself does not feed on plant tissues or cause damage, but it can block enough sunlight to affect photosynthesis which can weaken the plant over time. It is also very ugly and difficult remove (more on that in a bit).
The first step is to identify and treat the insect causing the problem:
- Soft or armored scale (look like small turtle shells affixed to the stems and/or leaves, sometimes very well-camouflaged in color or texture. Egg sacs are often wispy and white),
- Aphids (small green, yellow or tan insects with thin legs & antennae, wooly aphids look a bit like tiny sheep)
- Whitefly (tiny, white-winged flies).
A population of insects large enough to cause a sooty mold problem is usually pretty easy to spot and identify. Controlling the insects will stop the rain of sugar water that feeds the sooty mold.
The mold itself is difficult to remove, but you can hasten the rate at which it naturally weathers off. Spraying the leaves with insecticidal soap can help soften the sooty coating. Spray late in the day so the soap remains moist for as long as possible. If you can spray a few hours before a heavy rain is forecast the rain will be better able to remove the sooty mold.
If the plant has a rugged leaf, like holly or gardenia, you can follow the soap application with a strong jet of water from your garden hose after you’ve given the soap a little time to soften the mold. Be careful with softer-leafed plants and new growth, as a strong water stream can tear or bruise leaves. You’ll probably have to repeat the process a few times to wear the coating of sooty mold off over time.
If your insect eradication was successful, you’ll see that new growth on the sooty mold affected plants will remain fresh and clean. The mold does not spread without the honeydew to grow on, so new sooty mold indicates a continuing insect problem.

Sooty Mold

Bacterial leaf spots show as necrotic, circular or angular lesions and may have a yellowish outline or halo. Early symptoms of bacterial leaf spots show on older leaves and lesions appear water-soaked. Bacterial spots affecting dicytyledounous plants that have net-like leaf veins sometimes take a more angular shape as they are restricted by the large leaf veins. Bacterial spots on monocotyledonous plants with parallel leaf veins have a streak or striped appearance. The most obvious symptom of bacterial leaf spots are the blackening of the spots after infection. Eventually older lesions dry out and become papery in texture. Bacterial spots can also produce white, yellow, light cream or silver bacterial exudate depending on the type of bacteria, which may ooze from splitting lesions and/or from the underside of the spots. Bacterial leaf spots caused by Pseudomonas show red-brown spots which can distort the infected leaves, whilst those caused by Xanthomonas are angular or circular in shape outlined with a yellow halo.

Prevention of leaf spot disease includes variety selection, crop rotations, plant hygiene and fungicide use for seeds and foliage. To stop the spread of pathogens good sanitation is key as well as the avoidance of handling plants when wet, planting pathogen-free and resistant cultivars and moving out infected plants. Reducing the humidity around plants and in greenhouses by good plant spacing for air circulation, and watering early in the day can also help prevent leaf spot disease. Disinfection of tools and washing of hands is important when handling infected plants. Susceptibility to leaf spot disease can occur due to insufficient or excessive fertilising of plants. Checking plants periodically for any signs and symptoms of disease is also good practice. Avoiding overhead watering and increasing air circulation by pruning plants should be done to prevent humid conditions. Collecting and removing fallen leaves is important in reducing the amount of pathogenic agents on the ground to prevent dispersal of disease.

Certain chemicals are used to treat leaf spot disease, such as the Bordeaux mixture, the first fungicide to have been developed, which treats many fungal and bacterial leaf spots. Other fungicides such as zineb, chlorothalonil and Captan, also treat leaf spot disease and Benomyl specifically treats Cercospora leaf spots, cherry leaf spot and black spot of roses. Thiabendazole is used to treat leaf spot diseases of turf and ornamentals. Both fenarimol and nuarimol are pyrimidines that also treats leaf spot disease. More chemicals include Triazoles an organosphosphate fungicide, Imazalil, Procholora and Fentin hydroxide. Registered fungicides in use are thiophanate methyl, chlorothalonil, ferban and mancozeb.

Bacterial leaf spot

Leaves Go Yellow and Fall Off. Dropping Old and New Leaves Alike.  Wilting, Limp Leaves. Leaves Turning Splotchy Black or Dark Brown.  Mushy Roots Mean Overwatering.  An Overwatered Succulent Will Rot and Turn Mushy.

Soaking the ground for a longer period of time less often, and not watering by hand but using a sprinkler or soaker hose, is the way to handle that situation. Mulch around the plant will also help keep a more even level of moisture.

Move your plant to a shady area even if it is a full-sun plant. Remove any dead or dying leaves. These should be easily recognizable. Check your pot for proper drainage and, if possible, create additional air space around the roots. This will allow oxygen to reach the root zone. Remove any dead or dying roots and keep only the roots that are healthy. Water only when the soil is dry to the touch, but do not let it get too dry. You should also seize all fertilization at this point until the plant is healthy again. Treat with a fungicide.

Water excess and/or uneven watering

Symptoms usually involve necrotic, often water-soaked leaf spots, typically most severe on lower leaves. The spots may be very small at first but develop an angular shape as the movement of the bacteria is limited by leaf veins. Eventually several spots may enlarge, coalesce and cause death of mature leaves.

Reduce humidity to encourage dry foliage and avoid dripping within the greenhouse. Avoid splashing water from plant to plant.  Avoid excess moisture and late day irrigation.

Chemical treatments work best as a preventive measure. Copper-based plant protection products have bactericidal activity (kill bacteria) and can be effective. Disinfection products that contain hydrogen peroxide or quaternary ammonia are also available.

Gammaproteobacteria

Ascomycetes are characterized by septate hyphae with simple pores. Asexual reproduction by conidia. Sexual reproduction by ascospores, typically eight, in an ascus. Asci are often housed in a fruiting body or ascocarp e.g. cleistothecia or perithecia.

Good gardening habits and effective treatment help prevent, stop and control fungal disease: 

1. Start by planting healthy stock. ...
2. Choose planting sites based on plant needs. ...
3. Avoid overhead watering. ...
4. Water early in the day. ...
5. Don't crowd plants. ...
6. Don't work a wet garden. ...
7. Treat with a trusted, proven fungicide.

To control fungal outbreaks, as with bacteria, remove all infected plant parts, or plants. You may also choose to apply a fungicide. There are many products available for treatment, organically (copper, sulfur, and baking soda are common) or synthetically.

Ascomycetes

The typical signs are brown or black feeding punctures visible on the affected plant tissues. Another conspicuous sign is honey dew, a sweet excretion that is released by the sucking insect. Often ants are attracted to feed on the honey dew.

Most true bugs do not cause serious harm to established plants. Provide proper cultural care so plants are vigorous. Provide adequate irrigation. Avoid growing shade-adapted species in full sunlight.

Effective ways to get rid of these stink bugs include sealing the house, dusting treatment, spraying with nicotine water, and using insect repellents. Stink bugs, also referred to as shield bugs, are a group of flying insects that belong to the Pentatomidae family of the order Hemiptera.

Hemiptera

The first symptom is usually the appearance of minute yellow stippling on the upper surface of leaves that have mites on the undersides. Infested leaves generally become yellow and may drop off from plants. Red spider mites on the back of a leaf (left) and mite damage on a cucurbit leaf (right).

Host plant resistance can be a valuable component of an IPM system that is compatible with other control measures such as chemical control, and it makes beneficial natural enemies more effective. In many cases, even partially resistant cultivars are useful to enhance the efficacy of biocontrol agents.

Insecticidal soap or botanical insecticides can be used to spot treat heavily infested areas. On fruit trees, horticultural oil should be applied early in the season or late in the fall to destroy overwintering eggs. Dust on leaves, branches and fruit encourages mites.

Tetranychidae

Brown, yellow, gray, or straw-colored needles at tip of current season's growth; needles usually stunted and shoot may curl. Branch dieback. Small, black fruiting bodies on needles, cones, or shoot tissue. Cankers on stems or branches. Oozing resin that adheres to blighted needles.

Preventing the initial infection is a better strategy than attempting to cure a diseased tree. The first line of defense in preventing disease is planting disease free stock, planting in a disease free area, and selecting a disease resistant species. Beyond the selection of clean, resistant stock and planting location, trees that have proper water and nutrient management are healthier and less susceptible to Diplodia tip blight. Controlling wood boring insects that create wounds for Diplodia to exploit, is another cultural practice that can prevent disease. Poor airflow and high humidity are conditions that favor disease development; keeping grass and weeds trimmed down at the base of the tree allows for better airflow and can limit disease development. Once a tree is diseased, the goal is to limit the amount of inoculum present. The blighted needles and cones will have the pycnidia survival structures that contain thousands of spores. Remove debris from the base of the tree and destroy. During dry weather (not during Spring or early Summer), cut away infected shoots, cones, and branches. Sanitary techniques like sanitizing pruning tools between each cut will prevent further spread of the disease.

When disease pressure is high, chemical controls is advised. First, spray should occur early spring at candle elongation. Repeated sprays should occur every two weeks until needles reach full size. Fungicides containing the following active ingredients have been shown to be efficacious: chlorothalonil, methyl, thiophanate-methyl, mancozeb, and copper hydroxide with mancozeb. Always read and follow the label.

Sphaeropsis blight

Southern blight on plants is most likely to occur in the summer months when the soil is warm and moist. Symptoms include discolored lower leaves, wilted foliage, and plant collapse and it usually results in the death of the plant.

Preventing entry of the pathogen. Use of healthy, certified seeds of known origin. Careful cleaning of agricultural tools. Avoiding environmental conditions that favour development of the pathogen. Irrigation management. Plant density and growth habitats.

Soil solarization and certain organic amendments (e.g. composted chicken manure and rye-vetch green manure), as well as introducing certain Trichoderma spp. have also been shown to reduce plant death and number of sclerotia produced in the field in tomatoes. In addition to these cultural methods, chemical methods (e.g. fungicides) can also be employed.These methods all disrupt the production of mycelium and sclerotia, thus reducing the spread of disease.

Southern blight

A diagnostic feature of this disease is the presence of many dark-brown, pimple-like structures called pycnidia (fruiting bodies of the fungus) that are readily visible in the tan centers of the spots. When spots are numerous, affected leaves turn yellow and eventually shrivel up, brown, and drop off.

Use disease-free seed. There's no evidence that this fungus is carried by seeds, but err on the safe side and don't save seed from infected plants. Thoroughly processing the tomato seeds you are saving will also help rid the seeds of lingering diseases.
Start with a clean garden. Dispose of all affected plants. The fungus can over-winter on the debris of diseased plants. It's important to dispose of all the affected plants far away from the garden and the compost pile. Keep in mind that it may have spread to your potatoes and eggplants, too.
Avoid overhead watering. Water aids the spread of Septoria leaf spot. Keep it off the leaves as much as possible by watering at the base of the plant only. Of course, it's impossible to keep the rain off your plants, but every little bit helps.
Provide room for air circulation. Leave some space between your tomato plants so there is good airflow. Stake them so that they are not touching the ground and not all bunched together. Good air circulation is especially important during damp and rainy periods.
Mulch below the plants. A layer of mulch will help prevent spores on the ground from splashing up onto the lower leaves.
Plant next year's tomatoes in a different section of your garden. In small gardens, it's not always practical to rotate your crops, so good clean up and sanitation become even more important.

Removing infected leaves. Remove infected leaves immediately, and be sure to wash your hands and pruners thoroughly before working with uninfected plants.
Consider organic fungicide options. Fungicides containing either copper or potassium bicarbonate will help prevent the spreading of the disease. Begin spraying as soon as the first symptoms appear and follow the label directions for continued management.
Consider chemical fungicides. While chemical options are not ideal, they may be the only option for controlling advanced infections. One of the least toxic and most effective is chlorothalonil (sold under the names Fungonil and Daconil).

Septoria leaf spot

General symptoms can include one or more of the following symptoms: curling or cupped leaves, stunted growth, discolored leaves, or leaves with dead spots. The same herbicide may cause different symptoms on different plant species. Since herbicides do not leave a "calling card" like mites, insects, and diseases (but the damage they cause can be mistaken for herbicide damage), it is advised to rule these out first. Other disorders that produce symptoms that can resemble herbicide damage include virus diseases, adverse weather, salt damage, drought, soil compaction, misapplied fertilizers, root stress, and nutrient deficiencies. Excluding these as causes requires close examination of the site and attention to patterns. Is the pattern of damaged plants consistent with drifting spray? Is more than just one kind of plant affected? Did the symptoms appear within one or two days (in most cases) of the suspected application of an herbicide? Were any lawn weed control products used in the area, including weed and feed products containing an herbicide? The answer to these and other questions can help make a circumstantial case of herbicide damage.

Use shielded booms to minimize herbicide off-target movement. Use spray additives within label guidelines to reduce production of small spray droplets. This will result in less potential for drift. Avoid tank mix ammonium sulfate with volatile herbicides as ammonium sulfate increases volatility.

Organic strategies that help plants recover from herbicide damage are those that aid in maintaining plant vigor:  water during dry periods; fertilize with organic fertilizer according to a soil test report; and watch for and control any insect or disease problems using organic approaches.

Herbicide damage

Phyllosticta causes circular leaf spots with brown/reddish borders. The spots can be really large covering a large area of the leaf. Initial symptoms include small watersoaked regions on the leaves. lesions become more apparent with a ring-like pattern at alter stages.

Repeated applications of fungicides such as Dithane M45, Captan, Ferbam, Mancozeb or thiophanate-methylbased treatments will help control infection levels and can prevent new infections in healthy plants, but it is difficult if not impossible to completely eradicate the fungus in an infected host plant.

Remove and dispose of affected leaves from infected plants to keep the fungal spores from spreading into the growing environment. Some growers have reported covering the mature lesions with clear nail polish to prevent the dissemination of spores.

Phyllosticta leaf spots

Symptoms of infected plants are premature yellowing, dieback, wilting of older leaves, and stunting of plants, followed by death of all foliage and sometimes root rot. Unlike Botrytis species, S. cepivorum does not produce spores to spread and establish disease.

The hyperparasite Coniothyrium minitans may provide biological control, and a commercialized product ‘Contans’ is based on this.

Certain crops such as lettuce, beans and chicory can contribute to inoculum build-up significantly. Soil infestations can also be reduced by metam sodium and biological soil disinfestation.

Sclerotiniaceae

Cucurbits infected with tospovirus exhibit a variety of symptoms. Leaves can show bronzing to severe systemic chlorotic spotting. Other symptoms include leaf deformation, mosaic, die-back and overall plant stunting. Fruit symptoms can range from chlorotic ring spots on young fruit to necrotic lesions on older fruit.

Keep the greenhouse free of weeds inside and around the outside, since both thrips and tospoviruses are easily harbored in greenhouse weeds. When new cuttings or plugs arrive, check them for thrips or virus symptoms immediately. You can also employ virus indicator plants in the greenhouse.

Infected plants cannot be cured. Control measures aim to prevent or reduce the levels of disease in crops by removing or avoiding sources of virus infection and minimising spread by thrips.

Tospovirus

On the apple tree, the infections occur on leaves, fruit and young twigs. The brightly colored spots produced on the leaves make it easy to identify. Small, pale yellow spots appear on the upper surfaces of the leaves, usually during late April or May on the eastern seaboard of the United States. These spots gradually enlarge and turn orange or red and may show concentric rings of color. Drops of orange liquid may be visible on the spots. Later in the season, black dots appear on the orange spots on the upper leaf surface. In late summer, tube-like structures develop on the undersurface of the apple leaf. Infected leaves sometimes drop prematurely, particularly during drought conditions or when the tree is under additional stress. Infections on fruit are usually near the blossom end and are somewhat similar to the leaf lesions. On the eastern red cedar host, the fungus produces reddish-brown galls from 1⁄4–1 inch (6.4–25.4 mm) in diameter. These galls can be mistaken for cone structures by the uninitiated. After reaching a diameter of about 1⁄2 inch (13 mm), they show many small circular depressions. In the center of each depression is a small, pimple-like structure. In the spring these structures elongate into orange gelatinous protrusions or horns. The spore-bearing horns swell during rainy periods in April and May. The wind carries the microscopic spores to infect apple leaves, fruit and young twigs on trees within a radius of several miles of the infected tree. On other species of juniper more common in landscaping and bonsai, the sizes of the infections are reduced. Early in the infection, the galls are small bumps on the woody portions of the plant. They maintain the orange gelatinous form after the first warm rains of spring but generally on a greatly reduced scale.

Fungicide sprays applied in a timely manner are highly effective against the rust diseases during the apple cycle. Most sprays are applied four times at 7- to 10-day intervals, starting with pink bud on crabapples. These applications are to protect the apples from spores being released from the cedar host in mid-spring. If cedar apple rust disease is diagnosed on apple fruits and leaves it is far too late to spray. Systemic fungicides are available. Fungicides listed for use on apples can be used in July and August on the cedars to reduce infection. Application of fungicides to the junipers before and while they are in the infectious orange gelatinous state seems to reduce the severity of the outbreak.

Because apples are an economically important crop, control is usually focused there. Interruption of the disease cycle is the only effective method for control of the cedar apple rust. The recommended method of control is to “remove cedars located within a 1 mile (1.6 km) radius” of the apples to interrupt the disease cycle, though this method is seldom practical. For those doing bonsai, it is common to have the trees within feet of each other and on the central eastern seaboard of the United States, Eastern Red Cedar is a common first-growth conifer along roadsides.

Arabis Turrita

(Arabis Turrita)

What is the plant

Planting

Popularity

Water

Professional care guides

Possible diseases

More plants

Have a problem with such plant? You can contact one of our botanists