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AVRDC
International Cooperators'
Fact Sheet |
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Crucifer
Pests Cabbage
Looper |
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Damage Symptoms Leaves have ragged holes. The cabbage heads have internally bored holes. These areas contain frass and other insect remains. Seedlings are severely eaten and dead or stunted. The undersides of the leaves appear skeletonized between the veins. Insect Characteristics Chewing mouthparts. The caterpillar is light green with white or pale yellow stripes along the sides. It typically moves by arching the middle part of its body. The adult moth is active at night. Where to Look Early in the growing season, watch the growth of the seedlings. If chewing damage is evident and stunting occurs, hunt for the green caterpillars. Inspect the heads later for ragged chewing holes and internal boring damage. Technical information The damage caused by this insect is very similar to that caused by the imported cabbage worm. The female lays dome-shaped pale green eggs directly on the host plant. After feeding, the caterpillar pupates on leaves in loosely constructed cocoons. There may be several generations each year depending on ambient conditions. Other hosts include lettuce, beans, tomato, spinach, pea, turnip, potato, and sweet potato. |
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Control Biological: Looper is attacked by a large number of natural enemies. Parasitoids include Voria ruralis, Eucelatoria armigera, Microplitis brassicae, and Chelonus texanus among others. A nuclear polyhedrosis virus (NPV) is a major killer. The virus occurs naturally in soil and on plants. This virus has reduced looper infestation greatly in Taiwan. Chemical: Application of chemical insecticides should be considered during critical crop stages when sizable numbers of larvae are present or when control of adults is desirable. This insect has already developed resistance to a few insecticides. Please check local recommendations. NPV and Bacillus thuringiensis are equally effective as most chemical insecticides. These biological products should be preferred over chemicals to combat looper because of their safety toward a large number of natural enemies that can also assist in the control of looper. |
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Last updated: 2001. Information from: Field Guide: Insect Pests of Selected Vegetables in Tropical and Subtropical Asia. 1995. B.L. Parker, N.S. Talekar and M. Skinner. Publication 94-427. Pest control recommendations added. |
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