breeding

An insectary was established at the Kenya Agricultural Research Institute (KARI) research station, Katumani in Machakos, Kenya, in 1999, and has improved significantly over the years in its scale and quality of operation. The main purpose of this facility is to provide stemborers for use in resistance-screening studies, insect bioassays and for oviposition/feeding preference studies within KARI projects. The stemborers that are reared are: Chilo partellus (Swinhoe), Chilo orichalcocilliellus Strand, Eldana saccharina Walker (Lepidoptera: Pyralidae), Busseola fusca Fuller and Sesamia calamistis Hampson (Lepidoptera: Noctuidae), with the bulk of production being for the first two species due to their relatively higher demand for use in resistance screening studies. The insectaries, the rearing procedures used, problems encountered during rearing and the coping strategies are described. The stemborer supply has increased with time from 26,000 in the long rains (LR) 2000, to 961,689 stemborers in the long rains 2001. There have also been improvements in the quality of production, record keeping and in the supply system in terms of synchrony of the stemborer supply with the end-uses. As part of the efforts to improve the rearing techniques, a laboratory study was conducted to compare the survival to pupation stage of B.fusca larvae in large plastic jars (16 x 7.5 cm - 250 ml of diet - 20 larvae) compared to glass vials (7.5 x 2.5 cm - 15ml of diet - 1 larva). There was no significant difference in the survival to pupation of larvae reared in plastic containers (80.5%) and glass vials (85.2%). Since plastic container saves on the time of infestation (egg batches can be used), is less breakable and cheaper, it has now been adopted for the rearing of B. fusca at the Katumani insectary. Future plans on improvement of the rearing facility, production, and the techniques used, are discussed.