Submitted to: Journal of Insect Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/5/2011
Publication Date: 9/26/2011
Citation: Duan, J.J., Taylor, P.B., Fuester, R.W. 2011. Biology and life history of Balcha indica, an ectoparasitoid attacking the emerald ash borer, Agrilus planipennis, in North America. Journal of Insect Science. 11:127. Available:insectscience.org/11.127.
Interpretive Summary: The parasitic wasp, Balcha indica, is one of the natural enemies in North America that may be used for biological control of the emerald ash borer (EAB), an accidentally introduced invasive beetle from the Far East that has destroyed millions of ash trees in the U.S. This wasp attacks grubs (larval stage) of the EAB, which feed on the phloem tissues of ash trees under the bark. In this study, we investigated the biology and life history of this parasitic wasp and its potential for use in biological control of EAB. The female wasp, stings the beetle grub, paralyzing it, and then lays an egg on its exterior. The hatched wasp larva eventually consumes the beetle grub leaving only a few host remains. In the laboratory, this wasp took approximately 89 days to complete its life cycle (from egg to adult). Because of the long life span and egg-laying period of adults, this wasp is likely to have overlapping generations in North America, and may be capable of attacking EAB throughout the growing season. In addition, only female offspring are produced, thus its reproductive capacity can be easily enhanced. This result is valuable for developing biocontrols of EAB.
Technical Abstract: Balcha indica (Hymenoptera:Eupelmidae) is a solitary ectoparasitoid attacking larvae, prepupae, and pupae of the emerald ash borer (Agrilus planipennis Fairmaire). Its fecundity, oviposition rate, longevity and development time were determined in the laboratory. Lifetime fecundity averaged 36 eggs with a maximum of 94 eggs per female and adult longevity 59 days with a maximum of 117 days. Under the normal rearing condition (25 +/- 2 deg C, 65 +/- 10% RH, and L:D 14:10 hr photoperiod), B. indica took approximately 89 days to complete its life cycle (from egg to adult emergence) with a minimum of 47 d and maximum 178 d. Egg stage lasted for a maximum of four days with approximately 50% eggs hatched in less than two days. The development time of the first instars lasted for a maximum of 9 days; 50% of the first instars completed their development (i.e. molted to the next instar) in less than 5 days. Instars of the intermediate and final stage larvae (after molting of the first instars) were not distinguished until they reached the pupal stage and 50% of those larvae pupated approximately 62 days after adult oviposition. These results indicates that B. indica may not have more than two generations in the mid Atlantic and Midwest regions of US, where normal growing seasons (with average temperature >25oC) are normally less than six months (May – October). Because of the long life span and oviposition period of adults, however, B. indica is likely to have overlapping generations in those regions.