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The potato leafhopper is a sucking insect,
which removes plant sap directly from
the vascular system in the leaflet, petioles
and sometimes the stem. In the feeding
process the leafhopper injects a salivary
toxin that causes injury to the plant.
Feeding injury sometimes appears very
similar to disease symptoms or nutrient
imbalance. By adversely affecting the
vascular system, leafhoppers reduce photosynthesis,
decrease productivity, stunt the plant,
and sometimes kill the young seedlings.
The complex of symptoms produced by
feeding of the potato leafhopper adults
and nymphs on potatoes and beans has been
termed "hopperburn." The first sign of
hopperburn is whitening of the veins,
which appears within 2 days of feeding.
Affected areas soon become flaccid and
yellow in color, after which they desiccate,
turn brown and die. Leaf curling generally
accompanies the necrotic symptoms resulting
from leafhopper feeding. Other symptoms
of feeding injury on beans include stunting,
decrease in internodal growth and dropping
of flowers and pods.
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