Rhizoctonia is a fungus that is found in most soils and enters the plant through the roots or the stem at soil level. Prevention and Control: First of all, do not overwater and if you suspect Rhizoctonia may be your problem, decrease watering. If a plant is too far gone (all the leaves from the bottom up are wilted), remove it. If your plant is in a container, discard the soil too. Wash the pot with a 1 part bleach to 9 parts water solution. Fungicides can be used, according to label directions. Consult a professional for a legal recommendation of what fungicide to use.

Pest : Maggots

Maggots live in the soil, chew the root hairs off of plants and love to tunnel through root crops such as onions, garlic and leeks. They are about 1/3 of an inch long, glossy white and blunt-headed. Adults are dark grey flies that resemble the common housefly.

Prevenion and Control: Floating row covers or cheesecloth set over seedbeds in early spring may deter egg laying on young plants. Crop rotation is a must. Always remove and destroy infected plants. Beneficial nemtodes will prey on maggots as well. Till soil well in the fall to expose and destroy pupae.

Pest : Fungus Gnats and Shoreflies

Fungus Gnats or Shore fliesare small pesky flies which can often be a nuisance inside the home. About the size of fruit flies, they can be seen running on the soil surface of pots. They seem to favor wet soil conditions and may thrive in mixes containing hardwood bark or manure. While the worm-like larvae can cause root damage and adults can transmit plant diseases, they rarely cause severe plant damage.

Possible controls: avoid over-watering soil. Another option: use labelled insecticidal drenches against the juvenile stages. Adults can be controlled with recommended insecticides, as well. Encourage natural enemies such as parasitic nematodes in the garden.

Pest : Mealybugs

Small, wingless, dull-white, soft-bodied insects that produce a waxy powdery covering. They have piercing/sucking mouth parts that suck the sap out of plant tissue. Mealybugs often look like small pieces of cotton and they tend to congregate where leaves and stems branch. They attack a wide range of plants. The young tend to move around until they find a suitable feeding spot, then they hang out in colonies and feed. Mealybugs can weaken a plant leading to yellow foliage and leaf drop. They also produce a sweet substance called honeydew (coveted by ants) which can lead to an unattractive black surface fungal growth called sooty mold.

Prevention and Control: Isolate infested plants from those that are not. Consult your local garden center professional or the Cooperative Extension office in your county for a legal insecticide/chemical recommendation. Encourage natural enemies such as lady beetles in the garden to help reduce population levels of mealybugs.

Pest : Whiteflies

Whiteflies are small, winged insects that look like tiny moths, which attack many types of plants. The flying adult stage prefers the underside of leaves to feed and breed. Whiteflies can multiply quickly as a female can lay up to 500 eggs in a life span of 2 months. If a plant is infested with whiteflies, you will see a cloud of fleeing insects when the plant is disturbed. Whiteflies can weaken a plant, eventually leading to plant death if they are not checked. They can transmit many harmful plant viruses. They also produce a sweet substance called honeydew (coveted by ants) which can lead to an unattractive black surface fungal growth called sooty mold.

Possible controls: keep weeds down; use screening in windows to keep them out; remove infested plants away from non-infested plants; use a reflective mulch (aluminum foil) under plants (this repels whiteflies); trap with yellow sticky cards, apply labeled pesticides; encourage natural enemies such as parasitic wasps in the garden; and sometimes a good steady shower of water will wash them off the plant.

Pest : Aphids

Aphids are small, soft-bodied, slow-moving insects that suck fluids from plants. Aphids come in many colors, ranging from green to brown to black, and they may have wings. They attack a wide range of plant species causing stunting, deformed leaves and buds. They can transmit harmful plant viruses with their piercing/sucking mouthparts. Aphids, generally, are merely a nuisance, since it takes many of them to cause serious plant damage. However aphids do produce a sweet substance called honeydew (coveted by ants) which can lead to an unattractive black surface growth called sooty mold.

Aphids can increase quickly in numbers and each female can produce up to 250 live nymphs in the course of a month without mating. Aphids often appear when the environment changes - spring & fall. They're often massed at the tips of branches feeding on succulent tissue. Aphids are attracted to the color yellow and will often hitchhike on yellow clothing.

Prevention and Control: Keep weeds to an absolute minimum, especially around desirable plants. On edibles, wash off infected area of plant. Lady bugs and lacewings will feed on aphids in the garden. There are various products - organic and inorganic - that can be used to control aphids. Seek the recommendation of a professional and follow all label procedures to a tee.

Fungi : Powdery Mildew

Powdery Mildew is usually found on plants that do not have enough air circulation or adequate light. Problems are worse where nights are cool and days are warm and humid. The powdery white or gray fungus is usually found on the upper surface of leaves or fruit. Leaves will often turn yellow or brown, curl up, and drop off. New foliage emerges crinkled and distorted. Fruit will be dwarfed and often drops early.

Prevention and Control: Plant resistant varieties and space plants properly so they receive adequate light and air circulation. Always water from below, keeping water off the foliage. This is paramount for roses. Go easy on the nitrogen fertilizer. Apply fungicides according to label directions before problem becomes severe and follow directions exactly, not missing any required treatments. Sanitation is a must - clean up and remove all leaves, flowers, or debris in the fall and destroy.

Diseases : Pythium and Phytophtora Root Rot

Rot Rot, Pythium or Phytophthora occurs when soil moisture levels are excessively high and fungal spores present in the soil, come in contact with the susceptible plant. The base of stems discolor and shrink, and leaves further up the stalk wilt and die. Leaves near base are affected first. The roots will turn black and rot or break. This fungi can be introduced by using unsterilized soil mix or contaminated water.

Prevention and ControlRemove affected plants and their roots, and discard surrounding soil. Replace with plants that are not susceptible, and only use fresh, sterilized soil mix. Hold back on fertilizing too. Try not to over water plants and make sure that soil is well drained prior to planting. This fungus is not treatable by chemicals.

Rhizoctonia Root and Stem Rot symptoms look similar to Pythium Root Rot, but the Rhizoctonia fungus seems to thrive in well drained soils.

Fungi : Leaf Spots

Leaf spots are caused by fungi or bacteria. Brown or black spots and patches may be either ragged or circular, with a water soaked or yellow-edged appearance. Insects, rain, dirty garden tools, or even people can help its spread.

Prevention and Control: Remove infected leaves when the plant is dry. Leaves that collect around the base of the plant should be raked up and disposed of. Avoid overhead irrigation if possible; water should be directed at soil level. For fungal leaf spots, use a recommended fungicide according to label directions.

Pest : Leaf Miners

Leaf Miner is actually a term that applies to various larvae (of moths, beetles, and flies) that tunnel between upper and lower leaf surfaces, leaving a distinctive, squiggly pattern. A female adult can lay several hundred eggs inside the leaf which hatch and give rise to miners. Leaf miners attack ornamentals and vegetables.

Prevention and Control: Keep weeds down and scout individual plants for tell-tale squiggles. Pick and destroy these leaves and take advantage of natural enemies such as parasitic wasps. Know the Growing Degree Days (GDD)* for your area to target insecticide sprays when most beneficial for controlling the specific leafminer. Seek a professional recommendation and follow all label procedures to a tee. *GDD numbers should be available from your local Cooperative Extension office.

Diseases : Anthracnose

Anthracnose is the result of a plant infection, caused by a fungus, and may cause severe defoliation, especially in trees, but rarely results in death. Sunken patches on stems, fruit, leaves, or twigs, appear grayish brown, may appear watery, and have pinkish-tan spore masses that appear slime-like. On vegetables, spots may enlarge as fruit matures.

Prevention and Control: Try not to over water. If your climate is naturally rainy, grow resistant varieties. In the vegetable garden, stake and trellis plants to provide good air circulation so that plants may dry. Increase sunlight to plants by trimming limbs. Prune, remove, or destroy infected plants and remove all leaf debris. Select a fungicide that is labeled for anthracnose and the plant you are treating. Follow the label strictly.

Pest : Scale Insects

Scales are insects, related to mealybugs, that can be a problem on a wide variety of plants - indoor and outdoor. Young scales crawl until they find a good feeding site. The adult females then lose their legs and remain on a spot protected by its hard shell layer. They appear as bumps, often on the lower sides of leaves. They have piercing mouth parts that suck the sap out of plant tissue. Scales can weaken a plant leading to yellow foliage and leaf drop. They also produce a sweet substance called honeydew (coveted by ants) which can lead to an unattractive black surface fungal growth called sooty mold.

Prevention and Control: Once established they are hard to control. Isolate infested plants away from those that are not infested. Cosnult your local garden center professional or Cooperative Extension office in your county for a legal recommendation regarding their control. Encourage natural enemies such as parasitic wasps in the garden.

Weeds : Algae

Algae is a one-celled organism that reproduces by cell division, spores, or fragmentation. It thrives in warming water that receives full sun and has an ample supply of nutrients. Algae are most commonly found in ponds that that are not ecologically balanced or in low-lying areas on land or in drainage ditches. Most noticeable in spring, when water begins to warm, as a greenish cast or film on the pond's surface. On land, algae may appear slimy and green or scum-like. Prevention and Control: The best prevention is to strive for an ecologically balanced pond. It is recommended that you provide at least one oxygenating plant per 1 square foot of pond surface. Good oxygenators include charis, cabomba, and vallisneria, all of which compete with algae for carbon dioxide and nutrients. The second step would be to stop any fertilizer runoff from entering the pond and to reduce the amount of food fed to fish. Both overload water with nutrients, making algae problems worse. Reducing the amount of sunlight penetrating the pond's surface is the third step.

Fungi : Sooty Mold

Sooty mold is a fungus that is found on the surface of leaves. It feeds on honeydew excreted from aphids, mealybugs, scale, or ants. Though not serious, it is unattractive when it covers/blackens the leaves and stems of the plant. The best way to control sooty mold is to control the insects that make the honeydew. Sooty mold can usually be wiped from leaves with a damp cloth or washed away with a hose-end sprayer.

Diseases : Blight

Blights are cause by fungi or bacteria that kill plant tissue. Symptoms often show up as the rapid spotting or wilting of foliage. There are many different blights, specific to various plants, each requiring a varied method of control.