Biological control of bruchids (Col.: Bruchidae) in stored pulses by using egg parasitoids of the genus Uscana (Hym.: Trichogrammatidae): a review

Because small-scale farmers in the tropics tolerate some insect damage and hardly use insecticides, there is scope for alternative methods of insect pest control such as the use of natural enemies. The scarce literature on Uscana spp. is reviewed. For the biological control of bruchids in stored pulses several strategies can be considered. The first strategy, classical biological control, has only been attempted a few times. Currently under investigation is the introduction of the European egg paraSiloid Uscana senex for the control of Bruchus pisorum in Australia and ChilI. The second strategy, releasing laboratory-bred natural enemies for inoculation and inundation, requires a high level of technology and IS only appropriate for large-scale storage facilities. The third strategy of enhancing existing natural enemies by manipulation of the storage environment has not yet received much attention. Laboratory and field studies In the Netherlands and in Niger aim to achieve more effective control by the parasltoid Uscana lariophaga of the cowpea bruchid pests Callosobruchus maculatus and Bruchidlus atrolineatus in the field and in tradlbonal granaries. The paper discusses the results of studies on the effects of abiotic factors and nutrition on the development and performance of the parasitold