Some biological characteristics of Iranian strain of Microctonus aethiopoides (Hym.: Braconidae), parasitoid of alfalfa root and leaf weevils in Qazvin, Iran

Alfalfa weevil, Hypera postica Gyllenahl and alfalfa root weevil, Sitona discoideus Gyllenahl, are native insects of alfalfa (Medicago sativa L.) in Iran that causing sever damages. Microctonus aethiopoides Loan is a solitary endoparasitoid of adult weevils of the genera Hypera and Sitona. Life cycle of this wasp and its potential and potential as biological control agent were studied both in laboratory and field conditions during 2009 – 2010 in Qazvin, Iran. In laboratory experiments (26 ± 1 °C, 70 ± 10 % R.H., 10:14 (L:D) photoperiod), developing times for egg-larvae and pupae were 14.73 ± 0.34 and 6.03 ± 0.11 days for males and 15.16 ± 0.19 and 7.12 ± 0.23 days for female respectively. Parasitism rate achieved to 41 and 1% on H.postica and S.discoideus respectively. The sex ratio (M: F) was different for the first (overwintered wasps) and second generation (0:1 and 1:1.2 respectively).The parasitic wasp had two generations per year and the first and the second generations of this wasp emerged at early April and October respectively. Both generations of the parasitoid wasp were well synchronized with adults of both weevils, resulting in parasitism rates of 15-33% and 9-15% on alfalfa weevil in the first and second generations but not more than 0.7% on root weevil. First instar larvae of the wasp overwinter within adult stage of their hosts.