Causal Agent: 


Characteristic Symptoms:
Initial symptoms include mottling of interveinal tissues and green vein banding.
In severe cases, plants may show severe leaf curling or cupping and stunting.
Enations may also occur on the lower part of the leaf.
Transmission and Spread:
Downy mildew causes damage from the seedling (cotyledons) to harvesting stage.

The virus is retained by the vector for up to 20 days but not throughout the life span of the whitefly. The virus can be acquired by larval as well as adult stages of the insect, but is not transmitted to the progeny.

The virus is not transmitted through seed or by mechanical means.
Management and Control:
Use resistant/moderately resistant varieties, if available.
Plow in old crops as soon as harvesting is completed and ensure all crop residue is decomposed before planting.
Use virus-free seedlings.

Remove infected plants as early as symptoms are observed to prevent/minimize spread.

Remove weeds that serve as alternate hosts.
Adjust date of planting so that it does not coincide with high vector population.  
Control/minimize whitefly population by using plastic mulch, yellow sticky traps and/or use of insecticides such as imidacloprid (e.g. Confidor®, Admire®, Provado Supra®), metamidophos (e.g. Tamaron®, Matador®) and cartap hydrochloride (e.g. Padan®, Dimo®, Vegetox®).

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