SAP-FEEDING INSECTS
Some insects damage potato by sucking the cell sap from leaves or stems. The
aphids, whiteflies and
leafhoppers, all have beak-like
mouthparts that are used to suck sap from plants. Some of these insects also
produce toxic saliva, which they inject into plants. The best known example of
plant injury caused by saliva injection is a condition called hopper burn caused
by the potato
leafhoppers on Irish potatoes. Many of these insects also transmit
plant diseases. The green peach
aphids Myzus persicae, for example, is known to
transmit potato leaf-roll virus, PVY, PYS, PVA and PVM, while the whiteflies act
as vectors mainly for Gemini viruses (PALCV).
Mites
suck the cell sap from leaves and
young plant tissues leading to bronzing and curling and discoloration of leaves.