Common Species:
 
Aphis gossypii  - cotton aphids
   
Myzus persicae - green peach aphids
   
Aphis fabae - bean aphid
   
Common Name:
 

plant lice
   
greenflies
   
blackflies
   
Damaging Stage:
 
Adults and nymphs
   
Crops Afected:
 
Cucurbits, solanaceous, legumes, papaya, cotton
   
Characteristics Damage:
 
Initial damage due to feeding appears as light dots on the leaves.
   
High aphid population causes downward curling of leaves, stunted plant growth and wilting.
   
Aphids produce honeydew, a sticky exudate that serves as substrate for the growth of sooty mold.  It also interferes with the leaves’ photosynthesis and transpiration.
   

They are known vectors of different groups of viruses including Potyvirus (PRSV, ZYMV, ChiVMV), Luteovirus (CAYV/NMK) and Cucumovirus (CMV).
   
Control and Management:
Monitor the area regularly.
   
Remove weeds and volunteer plants that may serve as alternate hosts for the aphids.
   
Regulate use of nitrogen fertilizer, excessive nitrogen fertilization favors aphid reproduction.
   
Use yellow sticky traps to minimize aphid population.
   
Use plastic mulch to repel the aphids.
   
Use botanical extracts like neem, kakawate and hot pepper and canola oil.
   
Apply imidacloprid (e.g. Confidor®), methomyl (e.g. Lannate®), acephate (e.g. Acetam®) and  thiamethoxam (e.g. Actara®) when necessary.
   
References:

http://www.ipm.ucdavis.edu/PMG/PESTNOTES/pn7404.html

https://en.wikipedia.org/wiki/Aphid

Ebert TA, Cartwright B, 1997. Biology and ecology of Aphis gossypii Glover (Homoptera: Aphididae). Southwestern Entomologist, 22(1):116-153.