Biological fungicides are beneficial microbes that protect plants from soil-borne pathogens (like pythium and botrytis) as well as air-borne pathogens (like fire blight and powdery mildew). Biological fungicides supplement rather than harm biological life in soil. The mineral-based fungicides can actually harm the soil's life.
These are made from plants with pesticidal qualities. These materials, while safer to the user and the environment than chemical pest controls, are very strong and should be used as a last resort. Used inappropriately, these stronger botanicals (like rotenone, pyrethrin, and sabadilla) can cause more trouble by upsetting the biological balance and triggering secondary pest outbreaks. For severe situations they can be used on a temporary basis.
Neem oil is best as a preventative, or in low-disease-pressure situations, for fungus problems. Use it to control diseases such as powdery mildew, anthracnose, botrytis, rust, leaf spot, or flower blight.
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Used as dormant oils, growing-season sprays or spray adjuvants for smothering pests such as overwintering scales, mites, aphids, and peach twig borer. May be unnecessary for small scale users unless experience shows a serious problem with these pests. Many orchards do well and have never been sprayed with oils. In commercial applications or serious pest outbreaks, the use of oils may be necessary.
Generally considered acceptable for organic production, but should be used as a last resort. Other options are highly preferable to mineral-based fungicides because they do not harm beneficial microbial populations and leave soil’s “immune system” intact. As some people are sensitive to sulfur and copper-based materials, we especially recommend the use of respirator masks and protective clothing. Note that copper negatively affects the activity of microorganisms and earthworms, and it accumulates in the soil, so minimize its use. Sulfur, on the other hand, is assimilated by the plants and soil as a nutrient.
The strongest and most broad-spectrum fungus controls we offer. Use only when other techniques have failed. Copper can be detrimental to plants and soil when applied in rates above the recommended amounts. Often used in the dormant season. Read the label!
Sulfur is broad-spectrum with little detrimental environmental effects. Can be irritating to the eyes, ears, and nose during application. Used for the control of powdery mildew on grapes and other crops, it is effective against most species of pest mites, brown rot, rust, and scab. Often used in the dormant season.
Note to Certified Organic Farmers: While we do our best to stay current with product OMRI listings, be sure to check with your certifying organization for a current list of approved (or banned) products.