10 Glossary

Acclimate - To adapt to a new chemical, physical, or biological environment.

Active ingredients - The main inhibitory substance found in a pesticide.

Adsorption - The retention of solids, liquids, or gasses at an interface.

Aestivation - A period of inactivity during the summer months

Biosynthesis - The process by which living cells make molecules, tissues, or organs.

Bulk density- The mass of soil per unit volume.

Cation exchange capacity - The sum total of all exchangeable positively charged ions that a soil can adsorb. Expressed as milli equivalents per gram of soil.

Contact fungicide - Those fungicides that are active only on the external parts of plants.

Degree-day - A measure of how high the average daily temperature is relative to some reference temperature such as the minimum threshold required for insect development to proceed.

Disclosing solution - A liquid irritant that drives certain soil insects to the surface when the soil is drenched, such as a dilute soap or pyrethroid solution.

Disease trading - Increases in severity of nontarget diseases following fungicide applications.

Emulsion - Suspension of liquid droplets within another immiscible liquid.

Endophyte - A group of fungi that live within the plant and produce toxins detrimental to some plant-feeding insects.

Entomopathogenic - Causing disease in insects, such as certain fungi and nematodes.

Formulation - All of the ingredients and additives making up a given pesticide product.

Fungicidal - Treatments that kill fungal pathogens.

Fungistatic - Treatments that prevent fungal pathogens from growing or producing spores or prevent spores from germinating.

Habitat - The area or environment where an organism typically occurs, which provides the food, shelter and other requirements to reproduce and develop.

Half-life - The time required for half of the original amount of applied pesticide to disappear.

Immobilization - The reduction in movement of pesticides.

Inert ingredients - Those components of a formulation that have no pesticidal activity.

Inoculum - The pathogen or parts of the pathogen that can cause infection. Inoculum consists of spores, mycelium, sclerotia, etc.

Instar - The developmental stage of an insect between two successive molts.

Label - All of the written information that accompanies a pesticide. This includes the information affixed to the container as well as any other written material associated with the product.

Larva - The immature stage of an insect between egg and pupa for those groups with complete metamorphosis (egg, larva, pupa, adult), e.g. white grubs.

Leaching - The removal of pesticides dissolved in water from upper soil layers to the ground water.

Localized penetrant - Those fungicides that pass into the tissue underlying the point of application.

Metabolites - Products of microbial metabolism.

Microbial community - Interacting populations of microorganisms.

Mutualistic - A close association between two different species of organisms in which each derives a benefit.

Non-polar molecules - Molecules with no electrical charge.

Nymph - The immature stage of an insect between egg and adult for those groups with incomplete metamorphosis (egg, nymph, adult), e.g. hairy chinch bug.

Penetrant fungicide - Those fungicides that enter plant tissues.

Pheromone - A chemical secreted externally by an insect or other animal to communicate information to members of the same species.

Phloem - Food conducting tissue in a plant that moves sugar from the leaves down to the root system.

Photosynthate - The product of photosynthesis: carbohydrates.

Polar molecules - Molecules possessing two equal and opposite electrical charges.

Prepupa - A non-feeding and relatively inactive stage of an insect after the last larval molt and before the pupa.

Stomata - Pores in the surface of the foliar parts of plants that allow for gas and water exchange. (Stomate = singular).

Systemic penetrant - Those fungicides that pass into the plant tissues and are moved through the xylem and phloem to distant parts of the plant.

Translocation - The transfer and movement of pesticides through the plant.

Transpiration - The loss of water from the surface of leaves.

Vapor pressure - The pressure exerted by a pesticide in its gaseous state in equilibrium with that in the liquid state. A measure of the potential of a pesticide to convert to a gas.

Vascular system - The water and nutrient-conducting tissues of a plant.

Volatilization - The conversion of a pesticide from a liquid to a gaseous state and subsequent escape from soil.

Xylem - Nutrient- and water-conducting tissue in a plant that moves water and nutrients from the root system up to the above-ground portions of the plant.