فصلنامه تحقیقات آفات گیاهی
سال یازدهم شماره 3 (پاییز 1400)

Carob moth, Ectomyelois ceratoniae is a key pest in pomegranate orchards in Iran. The use of volatile plant compounds as one of the effective factors in changing the behavior of insects can be an important step in combating pests and thus reduce the use of pesticides and the risk to humans and the environment. In this regard, volatile organic compounds from the foliage and fruits of pomegranate trees of Kadro, Rabbab and Shirin Shahvar varieties were collected and identified by gas chromatography-mass spectrometry (GC-MS). Respectively, in foliage of mentioned pomegranate varieties, 17, 33 and 24, and in their fruit 42, 23 and 26 volatile organic compounds were identified. The most abundant constituents were 2,6-Dimethoxyphenol (51.01%) and 6- Aza-5,7,12,14 - tetrathiapentacene (36.92%) in Kadro foliage and fruit, respectively. They were in Bis (2-ethylhexyl) phthalate (46.37%) and 6-Aza-5,7,12,14-tetrathiapentacene (32.24%) respectively in Rabbab foliage and fruit. Besides, 9,17-Octadecadienal, (Z) (27.62%) and Benzoic acid-2,5-bis-(trimethylsiloxy)-trimethylsilyl ester (46.25%) were the major components respectively in foliage and fruit of Shirin Shahvar variety. Examination of the olfactory response of female insects of Carob moth in the wind tunnel showed that female insects were differently attracted to the odor of pomegranate foliage and fruits of Kadro, Rabbab and Shirin Shahvar cultivars by statistical analysis. These data may be useful in semiochemically-based management strategies in the pomegranate orchards such as mass trapping or deter of Carob moth or attraction of natural enemies.

Ectomyelois ceratoniae (Zeller) (Lep.: Pyrallidae) is one of the most important pests of pomegranate fruits in Iran. Depending on the type of the egg laying of female insects on the stamina located in the crown of flowers and fruits, the best way to reduce pest damage is to prevent fruit contamination. For this purpose, during a four-year study (2016-2020) in Shahreza county, the efficiency of covering pomegranate fruits crown with latex to reduce the damage of carob moth was investigated. The results showed that in all four years of study, latex coating of fruits significantly reduced the infestation of E. ceratoniae compared to the control. So that in 2016, a 98% reduction in the damage of this pest was observed in latex injection in fruits crown with dry stamens. In this research, the mean of weight and cracking percentage of pomegranate fruits treated with latex were not significantly different from the control. Finally, latex as a safe substance is recommended in fruit crown coating method for managing  pomegranate carob moth.

The greenhouse whitefly, Trialeurodes vaporarium (Westwood), is an invasive insect pest of agriculture and horticulture worldwide. Imidacloprid as chemical pesticide has been used as a key pesticide for controlling sap-sucking pests and play a major role in controlling this pest. The main purpose of this study was investigation of resistance status of T. vaporarium to imidacloprid SC 35% (Confidor®) and cross resistance to Eforia® and Proteus® and effect of imidacloprid resistance on Encarsia formosa Gahan. Thirteen greenhouse whitefly populations were collected from greenhouses and fields and used for tests. Collected populations reared on cucumber plants under laboratory conditions at 25±2˚C, 70±10 % relative humidity and a photoperiod of 16:8 h (L: D). The LC50 values were estimated on the second instar nymphs for all populations using leaf dipping bioassay method. The VGR population showed highest LC50 that was 856.2 mg/L. The development of resistance to imidacloprid was confirmed for all tested populations with resistance factors ranging from 2.54 to 44.3. The most resistant strain showed cross resistance to Eforia® and Proteus®. There was no significant difference between LC50 values of E. formosa populations that collected form field, reared on the most resistant population and sensitive population of T. vaporarium. The LC50s were 388.7, 324.7 and 317.7, respectively. We discuss our results in regard to the evolve of imidacloprid resistance in T. vaporariorum populations and its implications for whitefly control.

Deroceras agreste is one of the most important pests of greenhouses and lettuce fields, which reduces the quantity and quality of lettuce. Efficacy of seven treatments including 1- Lumakidin 5G® chemical bait, 2- Ferricol® bait, 3- combination of Lumakidin 5G ®with non-alcoholic beer trap, 4- combination of Ferricol® with non-alcoholic beer trap, combination of Lumakidin 5G® with milk trap, 6- combination of Ferricol® with milk trap and 7- control were evaluated in four replications in the greenhouse and lettuce field of Ghaemshahr, Mazandaran in 2019 and 2020. Counting the number of live slugs in the experimental plots were done one day before and 2, 4, 8, 14 and 21 days after the treatments. According to the results, in greenhouse and field, the use of non-alcoholic beer trap significantly increased the efficiency of Lumakidin 5G® and Ferricol® in controlling D. agreste. On the twenty-first day, the highest efficiency percentage (100% in greenhouse and field) obtained in Lumakidin 5G® treatment with non-alcoholic beer trap. In this day, the highest percentage of damaged lettuce leaves was in the control (about 70%) and then in Ferricol® (13.8% and 14.2% in the greenhouse and field, respectively). No eaten leaf area was observed in Lumakidin 5G® with non-alcoholic beer trap treatment. Therefore, the use of non-alcoholic beer trap in combination with Lumakidin 5G® and Ferricol® are recommended to increase the efficiency of these baits. Among them, Lumakidin 5G®with non-alcoholic beer trap having more effect in controlling D. agreste while is also more economical.

The family Tetranychidae includes the most important species of greenhouse pest mites, among which the two-spotted spider mite is the most important greenhouse pest. In this study, under stable conditions, the relationship between the population of the predatory mite Neoseiulus californicus (McGregor) and the biological stages of the two-spotted spider mite was investigated and a multiple linear regression model was fitted for these variables. It was found that the predator mite prefers the larval stage of the two-spotted spider mite with the highest beta coefficient (Beta= 0.795) over its other biological stages. The efficacy of four acaricides including Polaris® (chlorfenapyr SC 24%), Speed® (chlorfenapyr SC 24%), Flormite® (bifenazate SC 24%) and Dayabon3® (castor oil SL 10%) against this pest and its predator mite was based on a randomized complete block design. The results of the analysis of variance of mortality of egg, larvae, nymph and adult stages of this pest and its predatory mite with treatments on days 3, 7 and 14 after spraying showed that bifenazate 0.5 ml/l, castor oil 8 ml/l and chlorfenapyr (Polaris®) 0.5 ml/l were the highest percentage of mortality in all biological stages at different time intervals, respectively. According to the IOBC classification, the least dangerous compound for the predator mite was castor oil and bifenazate, and the most dangerous compound were both trade name of chlorfenapyr.

The parasitoid wasp, Telenomus busseolae Gahan (Hymenoptera: Plathygasteridae), has been extensively used to biological control of Sesamia cretica Led. (Hymenoptera: Plathygasteridae) in Khuzestan province, Iran. Due to dramatically population growth of S. cretica, the parasitoid wasp has not effectively controlled the pest during some seasons. Previous studies implicated physical control of S. cretica can be achieved using ultrasound. In this investigation, the effectivness of ultrasound on S. cretica to parasitism ability, sex ratio and distribution pattern of T. busseolae were evaluated under laboratory conditions. Results indicated that the ultrasound at frequency 37.5 KHz and Sin (X) wave shape has not significant effect on the wasp parasitism during various activity days. The parasitoid wasp treatment by the ultrasound did not significantly influenced the wasp sex ratio during 4 generations. Investigation on distribution pattern of exposed wasp showed that the wasp has random pattern, similar to control. The study indicated that T. busseolae cannot distinguish the ultrasound. Therefore, physical control of S. cretica using the ultrasound (at frequency 37.5 KHz and Sin (x) wave shape) has not any antagonistic effect to biological control by T. busseolae and the compatible strategies can be applied in integrated control of S. cretica.

During investigation on Guilan province mites fauna three species of parasitengone (Acari: Prostigmata: Erythraeidae) mites were collected and identified. Larval stage of Leptus (Leptus) trimaculatu, were separated on Ophion sp. (Ichneumondae) and Paederus fuscipes (Staphylinidae); Erythraeus (Zaracarus) budapestensis on Cicadella viridis (Cicadellidae) and Sogatella sp. (Delphacidae) and Charletonia krendowskyi on Stenotus binotatus (Miridae) and Sogatella sp. (Delphacidae) respectively. All three species are recorded for the first time from Guilan province. New hosts also have been introduced for these species.