Aphids
a result, the plant’s growth is retarded, giving rise to deformed leaves, or even, if the infestation occurs early enough in the season, the death of young [...] by piercing the plant tissue and sucking out the sap. This can result in stunted growth, curling or distortion of the leaves, yellowing, or discoloration [...] individuals. Potato virus Y (PVY) is transmitted by aphids in tomato in this way, as is the cucumber mosaic virus (CMV) in cucumber. How to get rid of aphids Horiver