فصلنامه تحقیقات حشره شناسی
سال دوازدهم شماره 3 (پیاپی 47، پاییز 1399)

The edible insects are consumed as an alternative animal protein source by most Asian countries. Since there is a limited evidence for their safety particularly from microbiological aspects, an attempt was made to assess the microbial population of Tenebrio molitor L. samples in laboratory conditions. Primary stocks were purchased from a local market, in Sari- a city in north of Iran. Microbial samples were prepared from both body surfaces and guts of insect. Samples were individually and cultured on nutrient agar (NA), incubated at taken 270C for 24-72h. Distinguished colonies were isolated and purified. Based on phenotypic characteristics, hypersensitive response (HR) on geranium leaves, as well as 16S rRNA gene sequencing analysis, the isolates were categorized into two groups. The pathogenic isolates were identified as Bacillus cereus, Staphylococcus sp, Pseudomonas aeruginosa, Enterobacter asburiae, Bacillus firmus and Serratia marcescens. Whereas, the nonpathogenic bacteria were assigned as Enterobacter cloacae and Bacillus thuringiensis. Undoubtedly, the presence of pathogenic microbes in the microflora of mealworm larvae by direct and indirect consumption of insect may pose a threat to human and animal health. These findings suggest an implementation of certain processing methods in order to decrease or eradicate risks of microbial contamination of diets using natural insects.

Effects bifenazate 24% SC doses (0.5 0.6, 0.7. ml/l) evaluated with spirodiclofen SC 240, fenazaquin  SC 20%, fenproximate 5% SC 5%, fenpropatrin, 10% FL on active stages of  Panonychus ulmi on red apple variety in East (Marand), West Azerbaijan (Oromia), Ardebil (Meshkeinshar) and Khorasan Razavi (Golmakan) provinces during 2010 . Blocked randomized design with three replications used and each replicate consisted four apple trees. Treatment done when mean of 5 mobile mite stages observed in 30% apple leaves collected randomly. Effects fo each treatment carried out by collection of 50 apples leaves and alive mite counted on upper leaf surface at one day before and 7, 14, 21 and 28 days accordingly. Mean active stages of P. ulmi mite/leaf found varied between 3.01 to 7.78 mites, 6.70 to 28.15mites, 3 to 36.66 mites and 17.43 to 26.83 mite among treatments in West Azerbaijan, Khorasan Razavi, East Azerbaijan and Ardebil respectively.  Highest mite mortality% threated by bifenazate doses up to 21 days after recorded 98.33% and 94.85% for 0.7 and 5 ml/l in Oromia and Golmakan, up to 14 and 7 days after observed 99.9% and 68.71% for 0.7 ml/l of bifenazate in  Marand and Meshkeinshar respectively. Bifenazate toxicity on mean of recorded natural enemies (predatory mites, Orius sp, and Thrips sp.) in Meshkeinshar reduced their number but did not eliminate them from apple trees. Higher doses of bifenazate application when mean of P. ulmi recorded lest than 5 mites on 30% of collected leaves, will provide effective control.

Bacillu thuringiensis (Bt) produces crystalline proteins that are toxic to various insect species. In this study, Bt strains were isolated from the soils of some areas of Fars province and their toxicity on larva of Plodia interpunctella (Hubner) was investigated. For this purpose, 110 strains were isolated from the soils of Shiraz, Marvdasht, Fasa and Sarvestan. Initial identification of the isolates was carried out on the basis of Gram staining and morphological characteristics of protein crystals using phase-contrast microscopy. The protein crystals of the isolates were spherical and rhombic. Molecular analysis by PCR showed that 40 isolates of the collection were contained Cry1 gene.The isolatestoxicity was studied on third instar larvae of P. interpunctella. According to the results of this study, 2×108 sporeml-1 concentration after 72 hours was considered as the most effective treatment and the three isolates sh20, g44 and FA-16 had the highest mortality (53.33%, 80% and 73.33%, respectively) onlarva of Indian meal moth. Isolates g46-29, g45-5, TA22, 35b, and E8 were ineffective on the third instar larvae of Indian meal moth. In general, the bioassay results showed that the strains isolated from the soils of the study area had considerable toxic effect on Indian meal moth larvae. We hope that introducing these native isolates of Bt will be an important step to produce domestic biological pesticides.

Cotton bollworm and corn stem borers are the most significant pests in the Middle East countries. Habrobracon hebetor is one of the most important parasitoid of some agricultural pests. In this study, we investigate the effect of cold storage on the biological parameters of Habrobrac wasp including percentage parasitism, reproduction, male generation in temperature 5 storage on the within 5, 10, 15, 20, 25 days in laboratory condition on the flour moth 30 days Anagasta kuehnilla (Zeller) that the experiments were conducted at 26ºc, 60 ± 5 % humidity  and 16:8 lightdark ratio. Based on these results, the most percentage parasitism (97.67%), reproduction (28.20 wasps) and adults longevity (7.60 days) were obtained in storage on the within 5 days that show significant difference in comparison with other storages. Also the obtained results show that time saving does not effect on the breeding but mass production of H. hebetor is improved and greatly enhances the performance of this biological agent in pest control.

During the investigations which were done to find Myzus persicae (Sulzer, 1776) and Trioxys pallidus (Kaltenbach, 1843) parasitoid for one year (2018-2019) in Markazi province. Sampling of the parasitized aphids by direct observation method was collected from different plants ( fruit trees, greenhouse crops (pepper and cucumber) and weeds) and transferred to the laboratory. The parasitic aphids, along with the host plant and a damp cotton, were then placed in containers with small net nets that the insects could not pass through. The ambient temperature was set at 25 ° C for them. After a few days, some mummified aphids of parasitoid bees were hatched from inside the body and some other hyperparasitoid wasps were hatched from inside the body. These parasitoid and hyperparasitoid wasps were collected and placed in 75% alcohol and then Identify. A parasitoid wasp collected from M. persicae under the species Aphidius platensis Brethes, 1913 (Hymenoptera: Braconidae), a hyperparasitoid collected from this parasitoid also called Pachyneuron aphidis (Bouché, 1834) (Hymenoptera) The parasitoid wasp that emerged from the mummified aphids Chromaphis Juglandicola  was also identified as  Trioxys pallidus (Haliday, 1833) (Hymenoptera: Braconidae). All three species are reported for the first time from Markazi province. A. platensis can be a good alternative to imported wasps in biological control against aphids in greenhouses.

The intrinsic rate of population increase (r) is one of the most important biological attributes of insects which is highly influenced by ambient temperature. In the present research, the response of Habrobracon hebetor (Say) (Hym.: Braconidae) intrinsic rate of population increase reared on Galleria mellonella L. (Lep.: Pyralidae) larvae was evaluated at 6 different temperatures (20, 22.5, 25, 27.5, 30, 32.5 ℃), 65±5% RH and 16:8 h L:D. For each temperature 80 to 250 fresh eggs of the wasp were reared as a cohort. The r was calculated using TWOSEX-MSChart software and obtained values were fitted to Briere-2 and Lactin-2 thermal models. Results showed that r was 0.0387 day-1 at 20 ℃ and increased to 0.0899 day-1 at 22.5, almost 2.3 folds higher. However, it was 0.1120 day-1 at 25 ℃ which only elevated 1.3 folds compared to that at 22.5 ℃. Nevertheless, the intrinsic rate of population increase of H. hebetor reached to its maximum value at 27.5 ℃ (0.2001 day-1), though, it decreased about 7.5 and 10% at 30 and 32.5 ℃, respectively. Thermal modelling proved that calculated values of r were almost identical to estimated ones only at low temperatures (20 and 22.5 ℃). In contrast, both models estimated H. hebetor intrinsic rate of population increase significantly lower compared with calculated ones at higher temperatures. Despite what was observed by calculations, Briere-2 and Lactin-2 models recorded the maximum r at 30 ℃ to be 0.1918 and 0.1922 day-1, respectively. It is recommended to consider insects’ life parameters estimations of thermal models along with real values.