فصلنامه تحقیقات آفات گیاهی
سال ششم شماره 3 (پاییز 1395)

Onion thrips, Thrips tabaci Lindeman, is a serious pest of a wide range of economically important crops in many parts of the world. Common bean, Phaseolus vulgaris L. is one of the most important host plants of this pest in Lorestan province. This research was conducted to investigate the resistance of ten genotypes of red common bean to T. tabaci under field conditions in Borujerd, Lorestan province, Iran in 2014. In this research the responses of T. tabaci to ten red common bean genotypes was examined in a randomized complete block design with three replications. The results showed that there were a significant differences among the number of Thrips on genotypes in different sampling dates. According to the number of first and second instar larvae of T. tabaci, out of 10 red common bean genotypes, KS31285 and KS31169, respectively, with average of 0.323 and 0.331 thrips/plant were as susceptible genotypes, KS31288, KS31286, KS31290, KS31292 and KS31287, respectively, with average of 0.210, 0.206, 0.262, 0.241 and 0.208 thrips/plant were as semi susceptible genotypes and KS31289, KS31291 and Goli, respectively, with average of 0.196, 0.179 and 0.191 thrips/plant were as resistant genotypes to T. tabaci.

Two spotted spider mite, Tetranychas urticae Koch is one of the most important pests of common bean, Phaseolus vulgaris L. fields in most regions of Iran. To deploy the appropriate management of this pest, in common bean fields, we need to construct a sampling plan that allows estimate population density quickly and accurately. During 2011-2012, spatial distribution and fixed precision sequential sampling plans of T. urticae population were investigated by the use of different sample unit sizes, in common bean fields in north of Lorestan province (Borujerd, Dorud and Azna). Regarding to the fitting of data with Taylor's power law, parameters of this method were used to develop the enumerative sequential sampling plans for each sample unit. Results showed that Taylor's b was significantly greater than 1, for all the life stages, indicating that T. urticae populations were aggregated. Comparison of Taylor's b for larvae, nymphs and adults, showed no significant difference among them. Therefore, Taylor's b and α re-estimated for total number of larvae鼩ꦆ쾚盩, without separating them. Sample size curves were calculated and compared at 10%, 15% and 25% levels of precision. Also, for each sample unit, Green's fixed precision sequential sampling plans were validated using 12 independent data sets. Validation results of these models showed that to achieve a precision of 0.25, which is generally accepted in IPM programs, it is necessary to take samples with an average sample number (ASN) of 146, 102 and 86 for sample units of 2, 4 and 6, respectively. In conclusion, the developed enumerative sequential sampling plans at precision level of 25% was recommended for monitoring this pest in irrigated common bean fields.

In this study, the effects of two isolates from the entomopathogenic fungus, Beauveria bassiana Boisduval were determined in immune system of the predatory hemipteran, Andrallus spinidens Fabricius (Hemiptera: Pentatomidae). Four types of hemocytes were identified in the hemolymph of the adult bug including prohemocytes, plasmatocytes, granulocytes and oenocytoids. Also, the effects of two entomopathogenic fungus isolates and latex bead were studied on the activity of phenoloxidase. The highest number of total hemocytes were found at time intervals of 12, 12, 48 and 48 hours post-injection by Tween80 (Control), latex bead, BB2 and AM-118, respectively. The highest number of plasmatocytes were determined 48, 48, 24 and 3 hours post-injection by Tween80 (Control), latex bead, BB2 and AM-118 but the number of granulocytes were observed after 48, 48, 12 and 12 hours, respectively. The highest number of nodules were observed 48, 48, 12 and 6 hours post-injection Tween80 (Control), latex bead, BB2 and AM-118, respectively. The highest activity of phenoloxidase were determined 6 hours post-injection by Tween80 (Control), BB2 and AM-118 and 3 hours post-injection by Tween80, respectively. To determine the gene of proPhenoloxidase, RNAs of the hemocytes were extracted and it was amplified by a pair of degenerate forward and reverse primers followed by cDNA synthesis. The results revealed a product with 675 bp based on reverse sequencing which had a 66% similarity with prophenoloxidase of Anasa tristis De Geer.Results of this study demonstrate that immune responses of the predacious hemipteran are different regarding various isolates of B. bassiana so the isolates should be used which have the lower virulence against the predator in integrated pest management programs.

The almond seed wasp, Eurytoma amygdali (Hym.: Eurytomidae) is a key pest of almond in Iran. The pest may destroy, in some cases, up to 90% of the almond seeds. Because of the pest importance and the lack of adequate information on its phenology in Isfahan, this study was carried out to investigate the phenology of the almond seed wasp. About 30% of the larvae showed prolonged diapause in the Zarainshahr region in 2015. The lower temperature threshold of the pest was estimated 7.214 °C and thermal constant for pupal stage under the laboratory conditions was 237.03±2.93 degree-days. Phenological study in Zarinshar showed that termination of pest pupation occurred in 30.3.2015 (by about 139 degree-days). Adult peak emergence occurred on 25.4.2015 (by about 358 degree-days). Peak of the egg laying was observed in 1.5.2015 (by 313.5 degree-days). Suitable fruit size for egg laying was estimated to be about 1.5×2.5 - 2.4×3.5 cm.

Study of behavioral parameters and functional response of predators is an important process in selecting these agents for biological control programs. In case of simultaneous use of these predatory insects with entomopathogens, behavioral reactions of predator may be altered. In this study, type of functional response of the predator, Orius niger (Hem.: Anthocoridae) was determined on the healthy adult female mite, Tetranychus urticae (Acari: Tetranychidae) and on the Beauveriabassiana-treated mites atthe four time intervals 0, 24, 48 and 72 hours at different densities of 5, 10, 20, 30, 40, 50 and 60 at 25 ± 1 ° C, 65 ± 5% RH and 16:8h (L:D) photoperiod. The results showed functional response of this predatory bug on untreated mites was type III while it was type II in other treatments. Comparison of searching efficiency and handling time in control with fungus treatments at various time intervals was only non-significant between control and 0 hour in searching efficiency and between control and 24 hours in handling time post-inoculation. The maximum attack rate (T/Th) in two treatments of 48 and 72 hours was reduced and was significantly different from other treatments; concomitantly handling time of predator was increased. These results suggest the effect of entomopathogenic fungus on behavioral reactions of predatory bug, O. niger.

The Sunn pest, Eurygaster integriceps Puton, is the most important pests of wheat and barley fields in Iran. Currently chemical control is the most common control measure of this pest. In this study, the lethal effects of three synthetic compounds, deltamethrin똘驲娩긧 (1000 ml/ha), lambda-cyhalothrin (75 ml/ha), deltamethrin (300 ml/ha) were compared with two commerical botanical extracts, Palizin® SL 65% and Sirinol® (1000 ml/ha) under the field and laboratory conditions. In the field study, a complete randomized block design with 4 replications was used on 3rd nymphal stages and overwintering adults in 2014 and 2015. The results showed that deltamethrin똘驲娩긧 and lambda-cyhalothrin with 100 and 90.1% mortality rates on adults were most efficient insecticides, respectively. Also, lambda-cyhalothrin and deltamethrin똘驲娩긧 with 100 and 96.38% mortality rates were most efficient insecticides on nymphal stages of Sunn pest, respectively. Contact bioassay in the laboratory indicated that the insecticide deltamethrin with LC50 1.35 and Sirinol® with LC50 of 2155 micro liter per liter were the most and least effective insecticides, respectively. Studies in both field and laboratory showed that; botanical extracts had less lethal effect compared with synthetic insecticides on the Sunn pest.

The damage of two bugs was observed in wheat fields of Galikesh in May, 2015. Both species belong to Miridae (Hemiptera: Heteroptera). One of the collected bugs was wingless and it is similar to ants. This species was identified as Myrmecophyes (Myrmecophyes) alacer Horváth. Thisinsect was observed in wheat fields of Farsian and neighboring villages. It was often observed at the margin of wheat fields and on some grass weeds. The damage of this bug has been observed as small white spots on leaf surface, specially at tip of wheat leaves. The other mirid bug, Grypocoris (Grypocoris) golestanicus Heiss, usually collected in the margins of wheat fields of Terjinly village. Its damage was almost same as the previous bug. This is the first association of these two mirid bugs in wheat field in Iran.

The pear thrips, Taeniothrips inconsequens (Uzel) (Thysanoptera: Thripidae) is one of the most important pests, that is recently causes damages to Montpellier maple trees in Zagros forests, Ilam province (western Iran). In this study, the natural enemies of maple thrips were collected and identified by monthly sampling of thrips from Gachan and Manesht Mountains, in year 2015. Results indicated that natural enemies included one larval parasitoid, Ceranisus menes (Walker) (Hymenoptera: Eulophidae), and 12 insects and mite predator species belonging to the nine following families: Aeolothripidae [Aeolothrips intermedius Bagnall], Thripidae [Scolothrips longicornisPriesner], Phlaeothripidae [Haplothrips flavitibia Williams, Haplothrips globiceps Bagnall], Anthocoridae [Anthocoris pilosus (Jakovlev), Orius laevigatus (Fieber), Orius niger (Wolff, 1811)], Miridae [Deraeocoris pallens (Reuter)], Nabidae [Nabis ferus (L.)], Coccinellidae [Coccinellaseptempunctata (L.)], Chrysopidae [Chrysoperla carnea (Stephens)], and Anystidae [Anystis baccarum (L.)]. All predators collected in this study were on maple trees along with maple thrips, among them A. intermedius and Orius spp. had higher population densities in contrast to other natural enemies.