Bionomics of Bracon ?hancocki (Wilkinson) (Hymenoptera: Braconidae), a Larval Parasite of Cydia Ptychora (Meyrick) (Lepidoptera: Tortricidae) in Nigeria

Bracon ?hancocki (Wlkn.) is a larval ectoparasite of Cydia ptychora (Meyr.), a major pest of cowpea at Ile-Ife, Nigeria. Parasitism occurred in the field all the year round, varying from 0 to 65·9% and with the highest incidence from September to February. In the laboratory, the fecundity of the parasite was low, averaging about six eggs per female. The life-cycle was completed in ten days. Mating occurred soon after emergence, and the preoviposition period lasted about 2–3 days. Unmated females rarely laid eggs, and their life-span averaged six days as compared to 14 days for mated females. The female:male ratio was 2:1. The parasite rarely attacked previously paralysed hosts, and the preferred hosts were the older, larger larvae. A description of the egg and larvae is given.

Oviposition preference by the black cowpea moth, Cydia ptychora (Meyrick) (Lepidoptera: Tortricidae), for different varieties of cowpea

In tests in Nigeria with its principal host-plant, cowpea, Cydia ptychora (Meyr.) showed distinct oviposition preferences. Most of the eggs were laid on the sepals (including their remains on pods) in screenhouse tests involving four varieties. There were distinct differences in the number of eggs laid on different varieties in both no-choice tests with four or five varieties and free-choice tests with 17 varieties in the field. Vita-3 was the preferred variety in the laboratory tests and H 13–1 in the larger comparisons in the field. Fewest eggs were deposited on Tvu 2994 in all tests.