Category: D

A virus that can only be transmitted through its vector when another virus, known as the “helper” virus, is present. This type of virus is also referred to as an assisted virus, carried virus, or helped virus.  

Rotting that proceeds at a rate which allows drying of the lesion to keep pace with lysis.  

A reduction in the total dimensions of the plant, while keeping the relative sizes of its individual components unchanged.  

The dispersal, as quantified by either the number or volume of droplets, of an atomized mist is distributed among defined ranges of droplet sizes.  

An agent that kills organisms present on the surface of plants or plant parts, or in the immediate environment, e.g. in soil.  

J. Grainger introduced a phrase to describe the biological state of a plant that influences its susceptibility to illness. The phrase is represented by the ratio of Cp/Rs, where Cp stands for the overall carbohydrate content of the entire plant, and Rs is the residual dry weight of the plant’s stem. This concept was initially…

The alteration in disease prevalence in relation to the proximity from the infectious origin point.  

the failure of a host to become diseased because of separation, in space or time, of susceptible host tissues and the infective units of the pathogen, e.g. an air-borne pathogen may not arrive in contact with the host until after the susceptible period has passed; climatic conditions may not permit the germination of a pathogen…

The stage of a serial dilution of cells or virus preparations at which growth or infection from a standard sample of the suspension no longer occurs.  

A host that elicits discerning responses between race-specific isolates of a pathogen, such as rust.