نشریه نامه انجمن حشره شناسی ایران
سال چهل و یکم شماره 4 (پیاپی 88، زمستان 1400)

Biological indices such as conidial morphology, germination, and surface characteristics influence the virulence of an isolate. Therefore, the growth indices (vegetative growth, conidiogenesis, and germination), hydrophobicity property and Pr1 protease enzyme activity of three isolates of Beauveria bassiana (JS1, JS2 and KA75) and TT1 isolate of Metarhizium anisopliae evaluated. Also, the relationship between these indices and the virulence of the isolates on the last instar larvae of Galleria mellonella and fourth instar larvae of Ephestia kuehniella investigated. There was no significant difference in vegetative growth rate between B. bassiana isolates, but the highest rate (7.05 cm) was related to the TT1 isolate. JS2 isolate showed the highest conidial production (4.11×106 spores / ml) compared to the other isolates evaluated. All isolates showed germination above 80%, and the highest value (100%) was related to the TT1 isolate, which was statistically on par with the conidiogenesis of the KA75 isolate. The lowest hydrophobicity of the conidial surface was related to KA75 isolate, which was significantly different from other isolates. However, the highest percentage was related to TT1 isolate with 91.7%. Also, no differences were observed between the isolates in terms of Pr1 enzyme activity. Bioassays showed that TT1 and JS2 isolates had the highest virulence on the last instar larvae of G. mellonella and fourth instar larvae of E. kuehniella, respectively. Among the evaluated indices, the hydrophobicity and conidiogenesis of these two isolates were higher than the other isolates, which was directly related to their high virulence. Thus, the TT1 isolate of the M. anisopliae and the JS2 isolates of B. bassiana had greater bioefficiency than the other isolates and therefore, they will be more suitable for use in plant pest biological control programs.

Olive fruit fly, Bactrocera oleae (Rossi) (Dip: Tephritidae), is one of the most important and main pests that attack olives  around the world, especially in Mediterranean countries. The fly larvae  seriously reduces olive production, and in some successful years due to the favorable weather conditions, they cause high economic damage to olives. This pest typically reduces the measurable quantity and superior quality of canned olives as well as olive oil after attacking olive fruits. In this study, the desired effect of specific temperatures was studied as the key environmental factor undoubtedly affecting the continuous growth of olive fruit flies. Development time of incubation period for egg,  larva, pupal stage, as well as total immature stages of the olive fruit fly were recorded in temperatures ranging 10-30°C, 60-70% RH, and a photoperiod of  16: 8 h (L:D). Based on the ANOVA, the specific temperature along the growth period inevitably affected significantly developmental time of the olive fruit fly at 5% probability level and the increase in temperature allegedly followed a decrease in developmental time. Degree-Day and Ikemoto linear models were used to describe temperature-dependent development of the olive fruit fly. Based on the obtained results in Siahpoush, Qushchi and Kallaj regions, the heat requirements for embryonic development of eggs were obtained 63.45, 71.28 and 63.68 days-degrees, for the egg+ larva stage were 209.18, 215.83 and 159.68 days-degrees, pupae stage were obtained 159.44, 183.15 and 175.55 days-degrees and the total immature stages were 348.51, 396.94 and 338.40 days-degrees, respectively, using Ikemoto model. In addition, the low threshold temperature of growth which estimated using Ikemoto linear model for the points mentioned were as follow: for embryonic developmental stages of eggs were 6.67, 6.33 and 6.71°C, for the egg + larva stage were 8.04, 6.96 and 9.43°C, for pupa stage were 9.72, 9.35 and 9.45°C and for the total immature stages were 9.31, 8.41 and 9.39°C, respectively.

Cabbage large white butterfly, Pieris brassicae is one of the important insect pests of plant family Brassicacea which causes remarkable quantitative or qualitative crop losses. Keeping in view the problems caused by conventional chemical insecticides, need is being felt for insecticides with more efficient and low-risk ones as well as biodegradable compounds. Nowadays, utilization of botanical plant compounds as bioenhancer and bioinsecticide are becoming increasingly important, due to their acceptable efficiency and relative safety to human and environment. To this end, we investigated the efficacy of chlorantraniliprole and lambda-cyhalothrin insecticides alone and in combination with Alhagi maurorum extract and cabbage seed oil against P. brassicae under laboratory conditions. Probit analysis revealed chlorantraniliprole as the most effective insecticide against egg, first, second and third instar larvae with LC50 values of 11, 4, 15 and 16 mg/l, respectively. Methanolic extract of A. maurorum when combined with chlorantraniliprole and lambdacyhalothrin possessed additive and synergistic effect, respectively. In bioassays, the addition of feeding stimulant improved the efficacy of the insecticides. The concentrations of chlorantraniliprole and lambdacyhalothrin required for 50 % mortality of all tested larval stages were reduced when the feeding stimulant was added in concentrations of 1 and 5 %. This information will guide future study and could be used as an effective tool for P. brassicae management strategies.

In the present study, species diversity of Encyrtidae and Pteromalidae (Hymenoptera: Chalcidoidea) parasitoid wasps were investigated in southern counties of Kerman province. The specimens were collected from 15 regions in 5 counties, using Malaise trap during 2015 and 2016. All obtained specimens were identified to species level and the number of each species per sample were counted. Species diversity and evenness indices of different regions were analyzed, using the software SDR4. A total of 40 species belonging to 25 genera and two families were registered in this research from southern regions of Kerman province. Among all species, Oencyrtus telenomicida (Vassiliev, 1904) with 39 specimens (22.3%) belonging to Encyrtidae and Halticoptera andriescui Mitroiu, 2005 with 28 specimens (16%) and Chlorocytus spicatus (Walker, 1835) with 20 specimens (12.1%) both belonging to Pteromalidae were the most abundant species, respectively. According to the studied indices, Bam had the highest species diversity and evenness among the studied regions. The highest similarity was also found between the wasp communities in Jiroft and Kahnuj.

Brevicoryne brassicae (L.) is one of the major pests of cruciferous crops that invades cabbage fields and leave white ash colonies. Due to the recommendation and suitable effect of chlorfluazuron against Plutella xylostella, in this study, the lethal and sub-lethal effect of this insecticide was evaluated on the population of cabbage aphid as a side pest. The method used in the experiments was insecticide spraying on leaves containing aphids. LC10 concentration (25.90 ppm) was used to investigate the sublethal effects of the insecticide on cabbage aphid. According to the results, the female lifespan/longevity was significantly reduced by sublethal concentration. The fertility mean of control and treatment exposed by chlorfluazuron sub lethal dose was 25.38 and 21.05 nymphs/female, respectively. Results indicated that the sublethal concentration (LC10) also affected progeny of treated adult aphids. Accordingly, the sublethal concentration of Chlorfluazuron significantly reduced intrinsic rate of increase (r) and finite rate of increase (λ) in comparison with control. Net reproductive rate (R0) in control and sublethal concentration treatment were 23.92 and 4.87 nymphs per female, respectively with meaningful difference. However, the mean generation time (T) between control and treated aphids have not considerable statistical difference. Based on the findings of the present study, even a very low concentration (LC10) of chlorfluazuron insecticide can be effective in cabbage aphid control and keep its population in low levels.

The cotton leafworm, Spodoptera littoralis (Boisd) (Lepidoptera: Noctuidae), is an important and polyphagous pest that causes considerable damage to agricultural crops in Iran and many other parts of the world. In this research, the effects of seven different leafy vegetables, including Purslane, Chives, Parsley, Basil, Dill, Coriander and Mint were assessed on the biological and life table parameters of S. littoralis at 25 ± 2°C, 60 ± 5% RH, and a photoperiod of 16:8 (L:D) hours. The longest development period was in the insects fed on Purslane (40.67 ± 9.49 days), and the shortest was obtained on Basil (30.22 ± 0.42 days) and Coriander (30.76 ± 0.32 days). The lowest value of fecundity was on the Purslane (199.32 ± 21.82 eggs), and the highest was recorded on the Coriander (481.06 ± 62.82 eggs), Basil (428.97 ± 28.68 eggs) and Chives (409.26 ± 26.58 eggs) vegetables. In addition, the results of demographic parameters showed that the intrinsic rate of increase (r) and net reproductive rate (R0) of S. littoralis were lowest on the Purslane (0.124 ± 0.072 day-1, and 67.92 ± 17.51 offspring, respectively), and highest values were observed on the Coriander (0.161 ± 0.064 day-1, and 275.70 ± 53.94 offspring, respectively). The cluster results indicated that Coriander was relatively susceptible host for feeding of S. littoralis. In contrast, the Purslane was found the relatively resistant (least appropriate) host for this pest, which could be useful in the development of integrated pest management strategies, and understanding plant-herbivore interactions.