Insect Management
Cotton Insect Management
Whiteflies - Trialeurodes abutilonea
Description
The adult whitefly is white and measures about 1/6 of an inch long. There
are three narrow brown bands across the wings. It has two pairs of wings and
flies readily when disturbed from resting areas on the underside of leaves. The
immature whitefly is flat and scale-like, about 1/30 of an inch long, doesn't
fly, and is found on the underside of leaves.
Biology
Whiteflies pass through four distinct stages of development. The eggs are
laid on the undersurface of leaves and hatch in four to five days. The young
larvae can crawl short distances but once the beak is inserted into the plant
they are stationary until the adult stage. The time for development to adult is
about 18 days. Several natural enemies prey upon whiteflies including lady
beetles, big-eyed bugs, and parasitic wasps. Alternate host for whiteflies
include tomatoes, hibiscus, cotton, and many other plants.
Damage
Cotton is damaged by adults and immature whiteflies who suck the sap from
the plant. Heavy populations may cause some defoliation. A sugary substance
called "honeydew" is excreted by whitefly larvae and accumulates on cotton lint
when bolls are opening. A black sooty mold may develop on the honeydew which
stains the cotton lint.
Whiteflies are seldom a problem in Arkansas.
Scouting
Whitefly populations are monitored by observing the number of whitefly
colonies in the terminal areas of cotton. When whiteflies are noticeable, count
the number of terminals that have whitefly clusters. Express as a percentage of
the terminals infested. Record according to the criteria listed below.
None - No whitefly present.
Light - 1 to 45% of terminals with whitefly.
Medium - 45 to 65% of terminals with whitefly infestations.
Heavy - 66% or more of terminals with whitefly infestations.
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