EFFECT OF PARASITOID AND HOST AGE ON OVIPOSITION AND EMERGENCE OF MICROPLITIS-CROCEIPES (HYMENOPTERA, BRACONIDAE) AN ENDOPARASITOID OF HELVICOVERPA ZEA (LEPIDOPTERA, NOCTUIDAE)

The effect of parasitoid age and two instars of the host Helicoverpa t ea (Boddie) were investigated for the endoparasitoid, Microplitis croc eipes (Cresson). Third and fourth instars of H. zea. were exposed to t hree different age ranges (3 to 5, 6 to 8, and 12 to 15-d-old) of mate d adult female M. croceipes. No significant differences were shown in rate of parasitism regardless of parasitoid age or host instar. Signif icant differences (P < 0.05) were found between parental age and adult wasp emergence, sex ratio, and number in pupal stage entering diapaus e. Six to 8-day-old parasitoids parasitizing third instar hosts yielde d the highest percentage of adult emergence (47.5 +/- 14%; ($) over ba r X +/- SD), the highest percentage of females (79%), and the lowest p ercentage (4.5 +/- 6%; ($) over bar X +/- S:D) entering diapause durin g the test.