Causal Agent: 

Potyvirus (Papaya ringspot virus type W or PRSV-W)

 

Characteristic Symptoms:
 
Leaves of affected plants show yellow mosaic, blisters and distinct vein banding (lighter color between veins with tissues adjacent to veins remaining green or vice versa).
   
In severe cases, leaf narrowing and distortion may be observed.
   
Transmission and Spread:
 
The virus is efficiently spread in a non-persistent manner by more than 20 aphid species, including Myzus persicae.
   
The virus is also easily transmitted mechanically through contaminated tools/implements.
   
There is no evidence of seed transmission.
   
The virus easily survives in wild cucurbits and in cultivated cucurbit crops grown year-round.
   
Management and Control:
 
Use tolerant  varieties, if available.
   
Remove infected plants as early as symptoms are observed to prevent/minimize spread.
   
Remove weeds that serve as alternate hosts.
   
Control/minimize aphid population by using plastic mulch, yellow sticky  traps and/or use of insecticides such as azadirachtin (neem), cartap hydrochloride (e.g.  PadanⓇ, Barena 50 SP, Gemtrak®), acetamiprid (e.g. MospilanⓇ), acephate (e.g. AcetamⓇ, CompeteⓇ), chlorphenapyr (e.g. Kotetsu) or penthoate (e.g. PennantⓇ, VidexⓇ).
   
References:
Compendium of Cucurbit Diseases (1996) by the American Phytopathological Society
   

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