Semi-Looper Worm, Autoba (Eublemma) gayneri (Roth.) (Lepidoptera: Noctuidae) as an Insect Pest on Maize in Egypt.

Abstract

Ecological and Biological studies of a semi-looper, Autoba gayneri (which is recorded for the first time on maize in Egypt) indicated the following: I- Ears of maize were attacked by this insect in governorates of Middle and Upper Egypt. 2- The rate of infested ears were increased with decreasing the space between maize hills, increasing of nitrogenous fertilization levels and decreasing the number of hoeing. 3- The early flowering hybrids were more susceptible than later ones. 4- The highest infestation occurred in two hybrids (TC 310 & TC321) with cob husks loosely covering ear tip, followed by (SC122 & SC124) with cob husks tightly covering ear tip. While the lowest infestation occurred in two hybrids (SC9 & TC 320) with ear head uncovered with husks. 5- A.gayneri attacked maize ears during the blister stage and continued until the physiologic maturing stage. The highest percentage of larvae and pupae on ears were recorded during the dough stage (60.07%). 6- This insect found attack three hosts: maize, sorghum and castor oil. 7- The number of annual generations were five generations under field conditions and ten generations under laboratory constant conditions (27 ± 1°C and 65 ± 5% R.H.). 8- The mean number of eggs laying on maize ears, sorghum panicles, silks, castor oil leaves, tassels and maize cob-husks were 219.57, 198.19, 149.10, 127.89, 118.30 and 44.70 eggs/female, respectively. 9- The duration of larval, pupal, female and male stages were (10.41, 11.65, 14.20, 11.80, 14.48 and 15.14 days, respectively); (9.08, 9.24, 9.92, 10.56, 10.14 and 10.22 days respectively); (21.92, 21, 21.70, 23.33, 20.40 and 19.53 days, respectively) and (18.78, 18.31, 18.30, 20.13, 15.80 and 17.70 days, respectively on maize ears, sorghum panicles, silks, castor oil leaves, tassels and maize cob-husks, respectively). 10- The semi-artificial diet contained maize grain powder is suitable for rearing larval stage of this insect, whereas the hatchability, pupation, adult emergence, pupal weight and fecundity were 89.25%, 89.25%, 87.14%, 100%, 27.64mg and 223.80 eggs/female, respectively. 11- A single larva consumed 1408.384mg maize ears during its span.