Damage to germination of seed corn caused by mayze weevil Sitophilus zeamais and angoumois grain moth Sitotroga cerealella.

Abstract

Damage by maize weevil and Angoumois grain moth (AGM) decreases the seed quality. Damaged seed if germinate produce a deficient plant. The life cycle of these insects, takes 35-50 days to complete. This research was undertaken to know the effect of these insects in their various developmental stages on germination. Comparing with the uninfested seed (control) with 95% germinative potential, the weevil preence in the egg stage (0-4 days old) reduced the germination in 13%, 1st instar larva (5-10 days) in 23%, 2nd instar (11-16 days) in 30%, 3rd instar (17-22 days) in 32%, 4th instar/pre-pupae (23-28 days) in 60%, pre-pupae/pupae (29-34 days) in 70% and pupae/adult (35-40 and 41-46 days) reduced germination in 94% and 93%. As to AGM only after 25 days the insect reduced germination significantly. Larvae of 3rd and 4th instar (25-30 dias) reduced in 43%, pupae (31-36 days) in 45% pupae/adult (37-42 e 43-48 days) in 49,7% and 63% the germination