Cabbage Integrated Pest Management : An Ecological Guide.

Major Cabbage Insect Pests¤Points to remember about webworm:1. Webworm caterpillars can locally be a serious pest, especially of nurseries and young transplants.2. Handpicking of caterpillars helps to prevent population build-up.3. Removing infested leaves or the main bud may be considered. The cabbage plant will compensateby producing more leaves and shoots.4. Bt applications can work against caterpillars but need to be applied before caterpillars areprotected inside the leaf or under webbing.Related exercises from CABI Bioscience/FAO manual:4-A.94-A.104.A.13Handpicking of eggs and caterpillarsIntegrated management of webworm on cabbageComparison of biological and chemical pesticides used in caterpillar control5.8 Cabbage looper - Trichoplusia niThere are several English names for this insect: cabbage looper, cabbage semilooper, ni moth or thefalse cabbage looper.DescriptionThe adult looper is a dark brownish moth with two small white markings on the forewings, sometimesresembling the figure “8”. Wingspan is about 35 mm. Adults live for about 3 weeks.The moths are night fliers, but can be seen during the day resting on the underside of cabbage leaves.The cabbage looper is a smooth yellow-green caterpillar with a whitish line down each side, and theforepart of the body slightly narrower than the rest. It can have two white lines along the middle of theback. Fully grown caterpillars measure 30 - 35 mm. There are two pairs of prolegs so a caterpillar walksby arching its body as a “looping” action which is characteristic for this insect. The caterpillars first eat onthe leaf borders but as they mature, they move deeper into the cabbage heads.The main host plant for the semi-looper are cruciferous crops but it can also feed on cotton, legumes,solanaceous crops like potato and tomato, sweet potato, some cucurbits and many other vegetables.Trichoplusia ni adult moth “looping” caterpillar PupaLife cycleEggs are laid singly on the underside of the lowest leaves, and hatch in about 2 - 3 days. Each femalecan lay up to 200 eggs. The eggs are white to yellow in color, round, about 0.5 mm in diameter and hatchin 2 to 3 days. The eggs are not securely glued to the leaf and can be brushed off easily.Cabbage Ecological Guide - 200098