Life history and feed ovipositional preference of Asian cornborer for Bt and non Bt-corn
2006
Sapin, G.B. | Adalla, C.B. | Alzona, F.D., Philippines Univ. Los Banos, College, Laguna (Philippines). Crop Protection Cluster
The field ovipositional preference of the Asian corn borer (ACB) Ostrinia furnacalis Guenee was determined during the dry and wet seasons of 2005 at the Central Experiment Station, UP Los Banos. Five varieties were used, namely: the transgenic variety YG818 and its isohybrid ORD 818, Tupi Yellow, IPB 929 and IPB 2006. The treatments were laid in RCB [random complete block] design with three replications. Egg mass count was started at whorl stage and terminated after tasselling period. The egg masses were marked for subsequent observations of predation and parasitization. Egg masses were more numerous in the wet season, than in the dry season. This indicates that high relative humidity and high rainfall are favorable for survival of ACB. Field parasitization was 58.01% in the wet season. Data were not recorded during the dry season due to the drying of egg masses and low population of natural enemies. Egg mass predation was 13.15% during the dry season, almost twice that of the wet season, which was 7.08%. However, the data indicated that there were no significant differences among the varieties tested regarding occurrence of oviposition, egg mass predation and parasitization. There was no clear ovipositional preference for any variety of the host plant, and variety did not have any impact on egg mass predation and parasitization. Thus, it can be said that Bt corn did not have any effect on the natural enemies of the ACB. The results of the study indicate that IPB 2006, IPB 929, and Tupi Yellow varieties can be used as structured refuges since egg mass counts did not differ significantly between any of these varieties and YG818. The natural enemies can have minimal or negligible effect on the evolution of resistance of the ACB since there were no significant differences in the rate of egg predation and parasitization on the different corn varieties tested.
Show more [+] Less [-]AGROVOC Keywords
Bibliographic information
This bibliographic record has been provided by University of the Philippines at Los Baños