Temperature-dependent life table parameters of Aphidius matricariae (Hym.: Braconidae), an important parasitoid of the currant lettuce aphid, Nasonovia ribisnigri (Hem.: Aphididae)

The effects of temperature on demographic parameters of the aphid parasitoid, Aphidius matricariae (Haliday), on lettuce aphid, Nasonovia ribisnigri Mosely, were studied at five constant temperatures, 15, 20, 22, 25 and 27 ± 1°C, 65 ± 5% RH and a photoperiod of 16L: 8D h. The life table parameters were estimated using age-stage, two-sex life table procedure. Moreover, the bootstrap method was used for estimating variance, mean and standard error of the population growth parameters, at studied temperatures. All estimated parameters were considerably affected by temperature. Accordingly, nymphs of N. ribisnigri could not settle and survive on the leaves at 27°C. Thus, mummies were not formed. Developmental time of the parasitoid wasp decreased with increasing temperature from 21.21 days at 15°C to 11.19 days at 25°C. The oviposition periods were 15.21±0.12, 9.47±0.10, 5.91±0.05 and 5.6±0.09 days at the temperatures of 15, 20, 22 and 25°C. Similarly, average number of mummies was 249.74±12.6, 192.72±12.8, 105.15±6.2 and 102.3±7.0, at the mentioned temperatures, respectively. The highest intrinsic rate of increase (r) and finite rate of increase (λ) were estimated to be 0.251 and 1.285 (d–1) at 20°C, respectively. However, there was no significant difference among the estimated values regarding intrinsic rate of increase and finite rate of increase at the temperatures of 20, 22 and 25°C. The highest value of net reproductive rate (R0) was 123.06 offspring/individual) at 15°C and the shortest mean generation time (T) was 13.98 (day) at 25°C. According to the obtained results, the temperatures 20-25°C, can be considered as optimal temperature range for the biological control of the currant lettuce aphid by using A. matricariae.