Agricultural Crop Disease Management - Category 1C - Iowa Commercial Pesticide Applicator Manual -

Plant Disease Any abnormal plant growth. Symptoms Visible effects of a plant disease on a host plant. Pathogen The parasitic organism that causes a disease. Plant Disease Triangle 1 - Susceptible Host Plant 2 - Pathogen 3 - Favorable Environment Host Plant being invaded by pathogen and serving as food source. Favorable Environment Environmental factors that allow the pathogen to invade the host plant. Environment The surroundings and/ or conditions that the plants exist in. Vector A virus transmitted by an insect. Stylet A needlelike structure found on plant-parasitic nematodes. Disease Cycle The chain of events involved in disease development. Inoculum Any material capable of producing infection and causing disease. Dissemination of Inoculum The spread or dispersal of a pathogen. Incubation Period The period between infection and the first appearance of symptoms. Economic Injury Level The density of a pest population when the cost of management equals the amount of crop lost by the pest. Economic Threshold The density of a pest population that justifies a management measure to keep an increasing population from reaching the economic injury level. Immune The pathogen cannot cause disease even under favorable conditions. Tolerant Even with a pathogen present, the plant can produce a good yield. Susceptible With a pathogen present, the plant(s) will be greatly damaged or killed by the pathogen. Fungicides Chemical or physical agents that kill or inhibit the growth of fungi. Chemical Name The name of an active ingredient in a fungicide. Common Name The non-technical term for the active ingredient or chemical name. Trade Name The patented name under which a product is commercially available. Contact Fungicides Remain on the surface of the plant where they are applied but do not go deeper. There is no after-infection activity. Systemic Fungicides Are absorbed into the plant tissue and may offer some after-infection activity. Preventative Activity Occurs when a fungicide is present on the plant as a protective barrier before the pathogen arrives or begins to develop. Early-Infection Activity Occurs when the active ingredient of a fungicide penetrates the plant and stopes the pathogen in the plant tissues. Anti-Sporulant Activity Prevents spores from being produced. Single-Site Fungicides Are active against only one point in one metabolic pathway in a fungus in one metabolic pathway in a fungus or against a single critical enzyme or protein needed by the fungus. Multi-Site Fungicides Affect a number of different metabolic sites within the fungus. FRAC Code (What does FRAC stand for?) Fungicide Resistance Action Committee Code Wettable Powders (WP) Fungicide formulations consisting of solid fungicide and a wetting agent. WP Fungicide (What does WP stand for?) Wettable Powders Water Soluble Pouches (WSP) Fungicides Fungicides that dissolve in the mixing tank and release the fungicide. WSP Fungicides (What does WSP stand for?) Water Soluble Pouches Dusts (D) Fungicides Powders mixed with inert ingredients to form a product with a low percent of active material. D Fungicides (What does D stand for?) Dusts Grannules (G) Fungicides The active ingredient is incorporated into small granules of inert material such as clay. Grannules are incorporated into the soil.