COMMON NAMESCMR-beetle (English); omanikanayi (Oshikwaluudhi); oumbambala (general name in Oshiwambo)PEST STATUSMylabris oculata is found on most farms in northern Namibia. It is usually seen on legume flowers, but M. oculata may also be found on flowering heads of pearl millet (Pennisetum glaucum). During the dry season, when there are no crops in the fields, M. oculata move in large numbers to the yellow flowers of the wild plant “Okashemetele” (Sesbania pachycarpa) or to the few plots of perennial pigeon pea (Cajanus cajan)DESCRIPTIONThe largest blister beetle, 25 mm long. Black with large yellow spots and a red band across the abdomen. The red band is sometimes changed into yellow spots as well. The antennae are orange or yellow.CONTROLIn most cases, they only cause limited damage, although M. oculata eats the petals of leguminous flowers. A few instances of severe damage have been observed, where M. oculata completely destroyed the flowers of cowpea (Vigna unguiculata) and also made holes in young pods.Most blister beetles are not considered important pests by local farmers, and they may not even be mentioned. Farmers get worried, however, in the rare cases when large numbers of beetles are found on flowering crops. Handpicking of beetles is not common, but at Onaanda in the Omusati region, an old farmer collected buckets full of beetles while working in the field. She mainly collected M. oculata and did not use gloves, although most species are known to give blisters. To speed up hand picking, one could use a simple homemade net for catching the flying beetles. Yellow traps such as soft drink cans filled with soapy water have been tested as traps for D. decorata, with no success. The beetles ignored the traps and went directly for the flowering pearl millet heads. The method needs further development and testing. It is therefore not recommended. The newest information from neighbouring countries indicate that red or blue traps are much more efficient for these beetles. Agricultural extension staff tested
chemical control of D. decorata in pearl millet and sorghum during
1998. Excellent control was achieved by using pyrethroids (Baythroid) or
carbaryl (Karbaspray). Chemical control is not advised, however, until
more is known about the possible damage caused by beetles and the economics
of chemical control. Spraying of crops such as pearl millet heads is very
dangerous as the spray boom is held from one to two meters above the ground
and operators may easily spray themselves in the face and eyes.
OTHER NOTESBlister beetles can give severe burns and blisters when handled. They exude a chemical that causes itching shortly after the chemical has touched human skin. A few hours later, large blisters begin to form and they stay for a day or two.
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