Parasitism of the leaf beetle Mesoplatys ochroptera in Eastern Zambia and implications for pest management in agroforestry systems
The leaf beetle, Mesoplatys ochroptera St l has recently become a serious pest of Sesbania sesban (L.), a nitrogen-fixing leguminous tree being eagerly adopted by farmers in short-rotation planted fallows for soil fertility improvement in eastern Zambia and elsewhere in Southern Africa. Surveys were conducted to identify parasites of M. ochroptera during the rainy season in 1998, 1999 and 2000 at several sites in the Eastern Province of Zambia. During the three years of rearing, no egg or pupal parasitoids were recovered from M. ochroptera . In contrast, two natural enemies, the braconid parasitoid Perilitus larvicida van Achterberg and the entomoparasitic nematode Hexamermis sp. were recorded for the first time from both larval and adult stages of the beetle. P. larvicida is one of the only parasitoids recorded as attacking and emerging from both the larval and adult stages of the same holometabolous insect host. Parasitism by the braconid and the nematode was low even during the peak population of the beetle in farmer's fields. Apparent parasitism due to P. larvicida was 4.5 and 5.5% in larvae and adults, respectively. Hexamermis sp. infections were recorded in 7.3% of the larvae and 0.3% of the adults. Both parasite species were also found in beetle populations on wild Sesbania spp. The potential for biological control of the beetle is discussed.
Biocontrol Science and Technology (2001) 11 (5) 611-622 [10.1080/09583150120076166]