Biological control of the larger grain borer
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CTA. 1991. Biological control of the larger grain borer. Spore 34. CTA, Wageningen, The Netherlands.
Permanent link to this item: http://hdl.handle.net/10568/45576
A predatory beetle from Costa Rica could soon be released in Togo to control the larger grain borer. In semi-field trials the beetle Teretriosoma nigrescens reduced larger grain borer populations by 70% in just over three months. In 1984 the German...
A predatory beetle from Costa Rica could soon be released in Togo to control the larger grain borer. In semi-field trials the beetle Teretriosoma nigrescens reduced larger grain borer populations by 70% in just over three months. In 1984 the German aid agency GTZ started a project to find a biological control agent. Since the larger grain borer is not a major problem in Latin America, where it is indigenous, scientists looked there to see what organisms might be providing control. Their research showed that the bacteria, fungi and protozoa which affect the borer m Costa Rica are also found in Africa. However, they did discover two predators in Costa Rica, Teretriosoma nigrescens and a species of Calliodis, which were not found in Africa. Tests with Calliodis showed that although it reduced borer population eventually, it was ineffective until populations were high and damage to the grain had already been done. T.nigrescens on the other hand showed that it was well adapted to its host, its population keeping in step wit-in that of the borer. The beetle can also survive for some time without food, should the borer population be reduced, and will not attack other insects such as bees or silkworms. T.nigrescens is attracted by pheromones given off by the borer. Trials are continuing but it is hoped that they can soon be completed by the release of the predatory beetles in Togo. GTZ, Versmannstr 4 2000 Hamburg ll, GERMANY