مریم آل عصفور

The future holds a projection of escalated occurrences of extreme climate events, which are expected to affect insect life substantially. Extensive research efforts in this field have witnessed rapid expansion despite significant gaps in knowledge. This review article addresses a deeper understanding of the impacts of severe climate events on insects that outline promising avenues for future research in this field. Drought has emerged as one of the predominant forms of extreme climate events that have extensively influenced insects, as frequently documented in the literature. The significance of drought occurrences on insects is crucial within the climate change scenario. Furthermore, the increasing occurrence and intensity of drought episodes, which are associated with changes in the climate, can result in elevated salinity levels in water bodies and soils. These changes have far-reaching implications for ecosystems, including impacts on biology, survival, and insect behavior. This review aims to analyze developments in information acquisition with anticipated climate change implications, particularly drought and salinity, on various aspects of insect life.

Nowadays, many researchers have paid attention to explaining the patterns of insect dispersion using interpolation and density estimation methods in order to investigate the possibility of proper integrated management with the location of pests. This study was conducted to predict and map the spatial distribution of the Coccinella septempunctata using multilayer perceptron neural networks (MLPs) combined with the imperialist competitive algorithm and shuffled frog leaping algorithm at the field level. Data have been obtained through100 samples taking from the surface of a hay field of zarghan area in 2019. To evaluate the neural networks used and compare their performance, statistical parameters such as statistical distribution, mean comparison and coefficient of explanation between the spatially predicted values by the neural network and their actual values were used to predict the distribution of this species. The results showed that in the training and experimental phases, there was no significant difference between the values of statistical distribution and the mean of real and predicted spatial data sets of this species combined by neural network with shuffled frog leaping algorithm. Shuffled frog leaping algorithm was more accurate in detecting the distribution. Our map showed that pest distribution was patchy

The fig spider mite, Eotetranychus hirsti Pritchard and Baker (Acari: Tetranychidae), is one of the most important pests of figs in Estahban city, which has the highest production of figs in Iran; Therefore, it is important to minimize the damage to this pest. It is important to choose the proper pesticide that has the highest mortality at the lowest possible concentration, has no adverse residue on the fig fruit, and has little environmental damage. In this regard, during 2016-2017, the acaricidal effect of abamectin, liquid sulfur, and a mixture of them was studied in order to determine LC50 and their synergistic effect in a completely randomized design including six treatments and four replications in vitro. This study was carried out at 28 ± 2°C, 55 ± 5 RH, and 16L:8D hours photoperiods. The results indicated a very strong synergistic effect in the application of a lethal concentration of zero percent liquid sulfur with very low amounts of abamectin, 0.06, 0.08, 0.1, 0.2 and 0.5 microliters per liter. Also, due to the significance of the LC50 ratio related to abamectin (The lack of number 1 in the confidencelimits), liquid sulfur, and the mixture of them, it is possible to understand the different effects of these compounds and due to the high mixing efficiency (reduction of 71.54 times in LD50).

Nowadays, with the advent of powerful statistical techniques and neural networks, predictive models of distribution have been rapidly developed in ecology. This study was carried out to model distribution of aphid, Rhopalosiphum padi,using MLP neural networks combined with Particle Swarm Optimization in wheat fields of Badjgah area, Fars province. Population data of the pest was obtained by sampling at 100 locations across wheat fields during 2013. For evaluation the capability of neural networks used in dispersal prediction, statistical comparison of parameters such as mean, variance, statistical distribution of spatial predicted values by neural network and their actual values, were conducted. Results showed that there were not significant differences between variance, mean and statistical distribution of actual and predicted values in training and test phases of neural network combined Particle Swarm Optimization algorithm. Our map showed a patchy pest distribution offers large potential for using site-specific pest control on this field.

In this research, a learning vector quantization neural network (LVQ) model was developed to predict the spatial distribution of Sitona humeralis in Marvdasht. This method was evaluated on data of pest density from alfalfa field. Pest density assessments were performed following a 10 m × 10 m grid pattern on the field and a total of 100 sampling units on field. Some statistical tests, such as means comparison, variance and statistical distribution were performed between the observed points samples data and the estimated pest values to evaluate the performance of prediction of pest distribution. The Results showed that in training and test phase, there were no significant differences, with the confidence level of 95%, between the statistical parameters such as average, variance, statistical distribution and also coefficient of determination in the observed and the estimated pest density. The results suggest that learning vector quantization (LVQ4) neural network can learn pest density model precisely. In addition the results also indicated that trained LVQ4 neural network had a high capability (88%) in predicting pest density for non-sampled points. The technique showed that the LVQNN could predict and map the spatial distribution of Sitona humeralis. The map showed that the pest has aggregation distribution so there is possibility potential for using site-specific pest control on this field.

The specimens of both sexes of Eremiothrips tamaricis (zur Strassen)were collected on tamarisk from Kohgiluyeh and Boyer-Ahmad province, south west of Iran. The male of the species is described and illustrated for the first time. It is unique among species of the genus in having transverse pore plates on abdominal sternites III and IV and the presence of small paired postero-marginal processes on tergite IX. The variation in number of posteromarginal setae on the pronotum, as well as host association for this species is briefly discussed.

RNA interference (RNAi) is a mechanism of post-transcriptional regulation of gene-expression, during which the introduced dsRNA results in target gene silencing through siRNA or miRNA pathways. Over the past few years, it has been shown that this approach has a great ability in management of insects including insect pests’ control, manipulated disease-carrying insects treatment and prevention of disease in beneficial insects. At least two pathways for dsRNA uptake in insects are described and among the various methods of dsRNA delivery, oral delivery of dsRNA is the best method for practical control of pests in the farm. Due to the success of RNAi method in pest control, it is expected that the method has a high potential for future pest management strategies, however due to the lack of genomic data for most exposed non-target organisms, it becomes difficult to understand the environmental risks caused by RNAi-based technologies and the benefits provided for the protection of crops. Further studies and better understanding the mechanisms of RNAi in insects would accelerate the world wide release of commercial RNAi-based methods.

The species Frankliniella occidentalis (Pergande),western flower thrips, is a highly polyphagous pest and an important vector of tospoviruses on several crops and ornamental plants. Western flower thrips has been introduced throughout the world and has been subject to many biological studies including mass rearing. In this survey, seven common mass rearing methods of F. occidentalis were described in detail and compared with each other. As a result, using Persian cucumber in plastic boxes by producing 6.15±0.4122 generations was selected as the best method. This method enables rearing multiple thrips generations on Persian cucumbers by using minimal supplies.

Between 2010 and 2011, spatial distribution and fixed precision sequential sampling plans were determined for two aphids, Rhopalosiphum maidis F. and Schizaphis graminum R., in wheat fields in Badjgah countryside of Iranian Fars province. For this purpose, two fields of two hectares each were selected and sampled on weekly basis. Each sample consisted of 200 randomly selected wheat plants along with the total number of counted aphids. Based on RV, the best sample unit was four stems. This data was used to describe spatial distribution pattern of R. maidis and S. graminum by Taylor’s power law (TPL) and Iwao’s patchiness regression methods. The results indicated aggregated spatial distribution of aphid's populations in wheat fields, based on the mentioned methods. The TPL provided a better description of the aphid's spatial distribution. Since regression line slopes were not significantly different for S. graminum and R. maidis, the same Green model was proposed for both species. In this model, minimum numbers of samples were 20, 12 and 9 for precision levels of 0.15, 0.25 and 0.3, respectively. Comparing Green and conventional methods in 0.15, 0.25 and 0.3 precision levels showed that the number of required samples were reduced 77.8 ± 1.05, 78.3 ± 0.91 and 81.4 ± 0.81 percent, respectively. Based on Wilson and Room's model, when the mean populations of aphids were 1.6, 3.86 and 5.62, the proportion of infestation in the field were 0.5, 0.75 and 0.85, respectively. Therefore, by increasing the infestation percentage of the samples, the number of required samples will be reduced.

Species of the genus Scirtothrips Shull are minute insects of which several are major pests on the leaves of various crops around the world. In this study, S. dorsalis is recorded for the first time from Iran. Body mainly yellow but antecostal ridge on tergites and sternites is dark brown and distal antennal segments are brown. Abdominal sternites covered with rows of microtrichia except anteromedially. A huge population of the species was collected in citrus orchards of Jahrom, Fars province, southern Iran in spring and summer of 2015. Thrips feeding causes several distortions on the leaves including narrowing and thickness on the leaves. On fruits, this pest punctures epidermal cells, leaving silvery scars or scabby on the rind. The effects of S. dorsalis on leaves as well as fruits are described and illustrated. The possibility of virus transmission by S. dorsalis has been discussed. Diagnosis characters as well as relative figures are provided.

An investigation was carried out to study the life history of Aphis nerri Boyer de Fonscolombe on oleander، Nerium oleander L.، under laboratory conditions (RH of 70 ± 5% and a 16:8 (L: D) h photoperiod) based on the age-stage، two-sex life table at 10، 15، 20، 25 and 30 ºC. Duration of total pre-adult stages was 35. 61 ± 0. 833، 19. 6 ± 0. 343، 12. 02 ± 0. 243، 9. 12 ± 0. 182 and 7. 42 ± 0. 115 days at 10، 15، 20، 25 and 30 ºC، respectively. As temperature increased، the developmental time and longevity of the A. nerri shortened. The shortest developmental time (17. 72 ± 0. 244 days) and longevity (10. 3 ± 0. 234 days) were obtained at 30 ºC. With decreasing temperature، age-stage survivorship (lx) extended. Maximum fecundity of females was observed at 25 ºC with 25. 54 ± 0. 76 nymphs per female. The intrinsic rates of increase (r) at these temperatures were 0. 012 ± 0. 0014، 0. 075 ± 0. 0016، 0. 13 ± 0. 001، 0. 23 ± 0. 003 and 0. 24 ± 0. 003 d-1، respectively. The highest net reproductive rate (R0) was at 25 ºC (25. 56 ± 0. 73) and the lowest value was at 10 ºC (2. 58 ± 0. 28). According to our results، 25-30 ºC were the optimum temperature range for A. nerri population growth.

Essential oils are volatile mixtures of hydrocarbons with diverse functional groups. In the current study the effect of essential oils from five medicinal plants including Zataria multiflora and Nepeta cataria (Lamiaceae), Tagetes minuta and Artemisia siberi (Asteraceae), and Trachyspermum ammi (Apiaceae) were analyzed using GC-mass spectrometry. The toxicity of these plant essential oils against the adult stage of the cabbage aphid, Brevicoryne brassicae L. (Hemiptera: Aphididae) was studied using a fumigant assay.GC/Mass analysis revealed that the main essential oils varied between species. The most abundant components in N. cataria, Z. multiflora, T. ammi, T. minuta and A. sieberi were 4a-α, 7-β, 7a-α-nepetalactone (76.8%), carvacrol (62.1%), γ-terpinene (27.1%), limonene (13.0%) and artemisia ketone (48.0%) respectively. The fumigant assays showed that all of these essential oils were toxic to B.brassicae in a dose-dependent manner. The essential oils of N. cataria at 126, 63, 31, 16, 8, and 3 μl L-1 air caused 94, 76, 52, 46, 36, and 24% mortality within 24 hours, respectively. The same trend was seen when essential oils of the other plants tested against B. brassicae. These plant essential oils have great potential to be used in integrated pest management especially in greenhouses or other closed systems.

A larval parasitoid of carob moth، Ectomyelois ceratoniae (Zeller)، was collected in pomegranate orchards in Fars province، Iran، during 2009-2010. This parasitoid، which is newly recorded from Iran، was identified as Goniozus legneri Gordh (Hym.: Bethylidae) by J. de Rond (Lelystad، The Netherlands).

The effect of fenpyroximate on life table parameters of two-spotted spider mite Tetranychus urticae Koch was evaluated under laboratory conditions (25±20C, 60±5% RH and 16:8 L:D). Data were analyzed on the basis of age-stage, two-sex life table theory. The estimated value of LC50 for T. urticae was found to be 380 Ml/l. Durations of total preadult stage and preoviposition period in T. urticae treated with fenpyroximate (12.64 and 2.36 d, respectively) were significantly longer than those in control (11.56 and 1d, respectively). The lifetime fecundity of T. urticae treated with fenpyroximate was 1.35 (eggs/female) compared with control (52.27 eggs/female).The instric rate of increase (r), finite rate of increase (λ), net reproductive rate (R0), the mean generation time (T) and Gross Reproduction Rate (GRR) in T. urticae treated with fenpyroximate were -0.001 d-1, 0.998 d, 0.96 offspring, 14.25 d, 2.94 offspring, respectively. The study shows that the LC50 of fenpyroximate decreases the fecundity of two-spotted spider mite under laboratory conditions and makes the pest population growth almost face extinction. So the acaricide can be effectively used in two-spotted spider mite control.