اثر حشره‌کش‌های سیرینول و سایرومازین بر پارامترهای دموگرافیک زنبور Habrobracon hebetor Say (Hym.: Braconidae)، اکتوپارازیتوئید kuehniella Zeller (Lep.: Pyralidae) Ephestia

The ectoparasitoid wasp, Habrobracon hebetor plays important role in population regulation of lepidopteran families Noctuidae and Pyralidae. In the present study, the sublethal effects of two insecticides including sirinol (botanical compound produced based on oily extract of garlic) and cyromazine (trigard®) (chitin synthesis inhibitor) were investigated on demographic parameters of H. hebetor wasp. Rearing of the parasitoid wasp were done on the last instar larvae of the Mediterranean flour moth Ephestia kuehniella (Lep.: Pyralidae) at 26±1°C, 70±5 % relative humidity and a photoperiod of 16: 8 (L: D) h. The bioassay of female wasps was carried out in contact exposure method in Petri dishes for 24 hours. Comparison of toxicity based on LC50 values (mg a.i./L) showed that cyromazine (10.24) was more toxic than sirinol (28.33). Then, for investigating of demographic parameters, eighty female wasps were treated with LC30 concentration of sirinol (4.04) and cyromazine (1.58) according to mg active ingredient per liter. After 24 hours, live females were paired with untreated males and their eggs counted daily until death time. Then, among laid eggs of them 100 eggs (under 24 h old) were selected randomly and the time of each biological stage and sex ratio of emerged adults were recorded daily to death time of all adults. The obtained results by jackknife and SPSS software showed that both insecticides had a negative effect on longevity, survival rate, daily and total fecundity and fertility; but, the sex ratio was only affected by sirinol compared with the control (0.54 to 0.58, respectively). The intrinsic rate of increase (rm) and finite rate of population increase (λ), which indicates the increase of females in the population compared with previous day for the control, sirinol and cyromazine treatments were 0.25, 0.15, 0.18 (per day) and 1.29, 1.16, 1.20 (per day). Also, net reproductive rate (R0) 116.65, 19.87, 45.91 (female offspring), gross reproductive rate (GRR) 254.63, 88.47, 168.21 female egg, doubling time (DT) and mean generation time (T) 2.76, 4.60, 3.77 and 18.92, 19.87 and 20.84 day respectively for the control, sirinol and cyromazine treatments were estimated. Therefore, by comparing the effects of sirinol on the life table parameters of H. hebetor compared to cyromazine, the use of cyromazine and H. hebetor wasp can be recommended synchronizely in integrated pest management programs.