Grootte 1,3 - 1,4 mm
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is a specialized whitefly predator in the lady beetle family.
The White Fly Predatory Beetle is a beetle often found associated with high populations of various species of White Fly. Adults are small, shiny, and are approximately 1.3 - 1.4 mm in length (1/15th inch). Adults are dark brown to black, hemispherical beetles; females have reddish yellow heads, lighter color than males.
Delphastus pusillus [related sp or synonym?] is a small ladybird from Florida with a wide distribution across the central and southern U.S. It is also found in Central America, the Caribbean and in South America as far south as Peru. D. pusillus attacks all species and stages of whiteflies, but prefers eggs and nymphs.
The adults are small (1/16 inch), shiny, black beetles. They are strong fliers that will immigrate into areas that contain high densities of whiteflies. D. pusillus responds to odors emitted by immature whiteflies, so it can find congregations of them easily among the foliage. The beetles tend to fly around more on overcast days.
Female beetles live for about 2 months, during which time they lay 3 to 4 eggs per day. (Male beetles live for 1½ months.) They generally lay their eggs within clusters of whitefly eggs, which makes it easier for the young larvae to find a food source. The eggs are 0.2 mm long, clear and twice as long as they are wide. The elongate larvae are pale yellow. Each instar lasts 1½-3 days. D. pusillus pupates on lower leaves, in leaf litter, or in other protected locations, often in groups. The pupal stage lasts approximately 6 days. Newly emerged adults are pale-brown to almost white. They eventually turn black with a brown head. Development from egg to adult takes approximately 3 weeks at 80-85ºF.
Both larvae and adults are active predators that can consume numerous eggs or nymphs each day. An adult Delphastus takes no longer than half a minute to handle a whitefly egg, and devours up to 160 eggs or 12 large nymphs daily. A larva consumes 1000 whitefly eggs (less if it also eats whitefly nymphs) during its entire development. Adults and larvae feed by piercing the insect with their mouthparts and alternately sucking and regurgitating the internal contents to digest and consume it. Adult females feed more on eggs and first instars
than on later stages.
Raymond A. Cloyd, University of Illinois