Insects and nematodes that attack cole crops in Southern Africa - a research review
1992
Daiber, K.C. (Vegetable and Ornamental Plant Research Institute, Pretoria (South Africa))
Diamond back moth, Plutella xylostella (L.), Bagrada bugs, Bagrada hilaris (Burm.), aphids, Brevicoryne braccicae (L.), Lipaphis erysimi (Kaltenbach), and Myzus persicae (Sulzer), thrips, Thrips tabaci Lindeman and Frankliniella occidentalis (Pergande) and the beet cyst nematode, Heterodera schachtii Schmidt are important pests of cole crops in southern Africa. Diamond back moth numbers increased in spring and autumm. Parasitoids and predators caused high mortality in early summer and a fungal disease spread during rainy spells and reduced the populations. Although Bagrada bugs produced high populations in some years, they were usually present in small numbers. Aphids were found throughout the year. With populations at their peak in summer, one parasitoid oviposited in all three aphid species but was frequently parasitized by hyperparasitoids. Syrphid larvae were abundant, but often heavily parasitized. The onion thrips and the western flower thrips have become important pests of cole crops. The beet cyst nematode was a threat to cole crops when these and other host crops were grown frequently on the same land
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