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Organic Disease Control

Organic Disease Control (and other issues)

The primary cause of plant disease problems is the use of high-nitrogen synthetic fertilizers and toxic chemical pesticides. Plant diseases are usually caused by three major types of living organisms: fungi, bacteria and viruses. Diseases are an imbalance of microorganisms. Reestablishing balance is the key to disease control. The reason the toxic chemical disease control products don’t work very well is that they kill more beneficial microbes than the targeted pests.

Disease control in an organic program is easy. And increased resistance to most diseases is a nice side benefit of the Basic Organic Program. All organic products help control disease to some degree. When soil and plants are healthy, there is a never-ending microscopic war waged between the good and bad microorganisms - and the good guys win. Disease problems are simply situations where the microorganisms have gotten out of balance.

Drainage is a key ingredient for the prevention of diseases. Beds, lawns and tree pits that hold water and don’t drain properly are the ideal breeding place for many disease organisms.  

	Animal damage: Damage to trunks and stems can result from the gnawing or antler rubbing of wildlife, especially rodents.
	Anthracnose: A fungal problem in sycamore trees, beans, and ornamentals where the foliage turns a tan color overnight. Sycamore leaves brown, remaining on the tree. Not normally fatal.
	Asparagus rust: Fungal disease that appears as a browning or reddening of the foliage, and a release of rusty, powdery spores.
	Bacteria: Single-cell microorganisms that reproduce by simple cell division. Most bacteria break down dead organic matter and are beneficial. A few, however, cause plant diseases.
	Bacterial blight: A bacterial disease that causes dark-green water spots that turn brown and may die leaving a hole in the leaves of tomatoes, plums, and several ornamental plants.
	Bacterial leaf scorch: A fatal disease of sycamores and other plants.
	Black spot: Common name of fungal leaf spot. Black spot attacks the foliage of plants such as roses. There is usually a yellow halo around the dark spot. Entire leaves then turn yellow and ultimately die.
	Canker: A stress-related disease of trees and shrubs that causes decay of the bark and wood.
	Cedar apple rust: Cedar-apple rust is just one of several similar fungal diseases that could be broadly classified as Juniper-Rosaceous rusts.
	Chlorosis: A condition caused in various plants by trace mineral deficiency. Iron scarcity is usually blamed, but the cause can be the lack of several trace minerals or magnesium or soils out of balance.
	Construction damage: Construction activity causes compaction of the soil which squeezes out oxygen and kills beneficial microbes and root hairs of trees and other plants.
	Cotton root rot: A fungal disease common in alkaline soils that attacks poorly adapted plants.
	Curly top: A viral disease that attacks vegetable crops such as tomatoes.
	Damping off: A fungal disease of emerging seedlings where tiny plants fall over as if severed at the ground line.
	Dollar spot: A fungal disease (Sclerotinia homeocarpa) that forms small brown spots on golf green grasses and other Bermuda turf grasses.
	Downy mildew: Fungal diseases that attack fruits, vegetables, flowers, and grasses.
	Early blight: A fungal disease that infects ornamental plants, vegetables, fruit trees, tomatoes, potatoes and peppers and shade trees.
	Entomosporium leaf spot: A fungal disease of photinia, hawthorns, and other related plants.
	Fairy Rings, Toadstools, Mushrooms: Mushrooms in lawns are common especially during rainy weather and not a concern at all.
	Fasciation: ​Fasciation, or cresting, is a rare of abnormal growth in vascular plants where the growing tips becomes elongated perpendicularly to the direction of growth, producing flattened, ribbon-like, crested or contorted tissue.
	Fireblight: A bacterial disease of plants in the rose family in which blossoms, new shoots, twigs and limbs die back as though they have been burned.
	Fungi: Fungi are microscopic primitive plants that lack chlorophyll, and produce tiny spores that are spread by wind, water, insects, and gardeners.
	Fungal Leaf Spot: See Entomosporium Leaf Spot.
	Galls: Swollen masses of abnormal plant tissue caused by fungi, bacteria or insects.
	Gray leaf spot: A disease of St. Augustine grass that forms gray vertical spots on the grass blades.
	Herbicide damage: Most, if not all, of the toxic chemical herbicides can cause plant problems.
	Hypoxylon Canker: Hypoxylon canker is common throughout the South on oaks and other hardwoods where it normally occurs on stressed hosts.
	Iron deficiency: A nutrient deficiency that causes leaves to turn yellow with the veins remaining green.
	Italian Cypress Canker: Some in the business incorrectly diagnose the dead brown spots in the plants as spider mites.
	Lichen: Growth seen on rocks and the trunks of trees commonly growing in flat greenish, gray, brown, yellow or black patches.
	Lightning damage: If your tree gets hit, keep your fingers crossed.
	Oak leaf blister: A rare disease that needs no control.
	Oak Wilt: A disease of the vascular system of oak trees which is transmitted through the air by insects and through the root system of neighboring trees by natural grafting.
	Powdery mildew: This fungal disease is a white or gray, powdery, growth on the lower leaf surface and flower buds of zinnias, crape myrtles, and many vegetables, phlox, lilac, melons, cucumbers, and many other plants.
	Rose Rosette: Saying there is no cure for the virus rose rosette is lazy and wrong.
	Rust: Fungal disease that forms an orange stain on the surface of foliage. Pustules form on the underside of leaves.
	Scab: Fungal diseases that cause fruit, leaves, and tubers to develop areas of hardened and sometimes cracked tissue.
	Slime flux: Slime flux is the foul-smelling sap that oozes out of wounds in the bark and wood, particularly on such trees as elm, maple, and birch.
	Slime mold: Slime mold sounds worse than it is. Slime molds cover mulch or some above-ground plants with a dusty-gray, black, tan, white, red or dirty above-ground plants with a dusty-gray, black, or dirty yellow mass.
	Smut: Fungal diseases common to grasses, grains, and corn.
	Sooty mold: Black fungal growth on the foliage of plants such as gardenias, crape myrtles, and other plants infested with aphids, scale, or whiteflies.
	St. Augustine decline: Is caused by the panicum mosaic virus in common St. Augustine grass that causes a yellow mottling.
	Take all patch: A disease that can attack several species of grass.
	Wet wood: Bacterial wet wood on trees shows up as oozing cell sap, a white frosty material that attracts insects.

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