فصلنامه تحقیقات آفات گیاهی
سال دوازدهم شماره 2 (تابستان 1401)

In previous study, nano hollow silica spheres have been synthesized by sol-gel method as a Mentha longifolia essential oil carrier and the success of essential oil encapsulation has been characterized based on particle size, polydispersity index, zeta potential, and encapsulation efficiency. The present research has been carried out on the findings of the previous study with the aim of evaluating 1) fumigant toxicity of Mentha longifolia free (M. EO) and nanoencapsulated (M. NP) essential oil against eggs, fifth instar larvae and adults of Anagasta kuehniella after 24, 48 and 72 h of exposure 2) topical toxicity of M. EO and M. NP against fifth instar larvae (mortality data obtained after 72 h exposure) 3) lifetime fecundity, %fertility, %adult emergence and copulation rate of A. kuehniella exposed to LC25 of M. EO and M. NP for 72 h. Fumigant toxicity was positively affected by the essential oil concentration and exposure time. Findings indicated that nanoencapsulation was associated with a 1.62-fold increase in the topical toxicity of M. longifolia essential oil to fifth instar larvae. Moreover, exposure to LC25 of M. EO and M. NP significantly decreased biological parameters (lifetime fecundity: 63 and 42 egg/female, percentage of fertility: 19.1 and 17.6%, percentage of adult emergence: 16.4 and 11.3%, copulation rate: 6.18 and 3.6% respectively). It is clear from the toxicological tests that nanoencapsulated essential oil produced stronger lethal and sublethal effects on A. kuehniella than free essential oil, thus can be regarded as potentially complementary or alternative to conventional insecticides in stored commodities.

Brevicoryne brassicae (L.) is one of the important and economic pests of Cole crops in Iran. One of the main methods to protect plants against aphids is using chemical pesticides. In this study, the sublethal effects of Chlorfluazuron was evaluated on the population growth parameters of cabbage aphid under greenhouse condition. The method used in the experiments was insecticide spraying on the leaves containing aphids. LC25 (105.60 ppm) concentration was used to investigate the sublethal effect of insecticides on aphid. The results showed that lifespan/longevity and fertility of the treated adult aphids were significantly affected by the sublethal concentration. Total longevity reduced from 12.78 days in control treatment to 8.14 days in sublethal concentration. The results of present study indicated that sublethal concentration also affected progeny of treated adult aphids. Accordingly, the sublethal concentration of the studied insecticide decreased the values of the intrinsic rate of increase (r) compared to the control treatment. Other population growth parameters such as net reproductive rate (R0), finite rate of increase (λ) and gross reproductive rate (GRR) were also significantly lower than the control. Decreasing the growth rate in sublethal treatment increased mean generation time (T). Based on research findings, Chlorfluazuron can be suitable for use in the management of the cabbage aphid, other than the recommended pest (diamondback moth).

The lesser grain borer, R. dominica, causes extensive quantitative and qualitative loses on stored cereal grains. The use of synthetic chemicals in the management of such insect pests resulted in several side effects such as environmental contamination, potential impacts on human health and development of pest resistance. Promising insecticidal potential of the essential oils isolated from several species of Eucalyptus genous against insect pests was shown in recent study. In this study, the lethal and sublethal effects of E. oleosa essential oil were investigaetd against the adults of R. dominica.  Chemical analysis of the essential oil indicated that terpenes, including 1,8-cineole, α-pinene, trans-pinocarveol, (s)-α-terpineol, and β-eudesmol, had high amount. The adult insects were susceptible to the fumigation of essential oil so that LC50 (Lethal Concentration to kill 50% of insects) values were estimated as ‎42.923, ‎35.828, and ‎34.044 µl/l air after 24, 48 and 72 h, respectively. Despite increases in a- and β-estearse enzymes, total protein, glycogen, and lipid contents and digestive amylolytic and proteolytic activities of the adults treated with LC30 (Lethal Concentration to kill 30% of insects) of essential oil were significantly decreased in comparision with the control. The consumption index (CI), relative consumption rate (RCR), and relative growth rate (RGR) were also significantly decreased in treated adults. A 59.40% feeding deterrence index (FDI) was evaluated for insects treated with LC30 of  the essential oil. According to observed lethal and sublethal effects, the essential oil of E. oleosa can be considered in further investigations in the management of R. dominica.

Mesostigmatid mites are a large group with a global distribution. In a faunistic study on mesostigmatid mites (Acari: Mesostigmata) associated with ants in Chaharmahal va Bakhtiari Province during 2020–2021, samples were collected from different parts, their mites extracted using Berlese funnels, cleared in lactic acid and then identified after mounting in Hoyer's medium on microscope slides. Totally, 35 mite species belonging to 23 genera and 11 families of Mesostigmata were collected from the nests of 15 species of ants. Among them, two families, one subfamily, five genera and nine species are reported for the first time from Chaharmahal va Bakhtiari Province, also 13 species are recorded for the first time from ant nests from Iran, which are marked with asterisk and circle in tables 2 and 3, respectively. Additionally, Pergamasus (Thenargamasus) quisquiliarus (G. and R. Canestrini, 1882), Laelaspis elongatus Kazemi, Mehrzad and Latifi, 2016, Pseudoalliphis sculpturatus Karg, 1963 and Arctoseius minutus (Halbert, 1915) are reported for the second time from Iran.

Integrated management with emphasis on combination of biocontrol agents and resistant varieties can be one of the efficient strategies to manage the pests. In this study, the effect of susceptible ('Orange') and resistant ('Tea') rose cultivars on demographic parameters of the rose aphid, Macrosiphum rosae (L.) (Hem.: Aphididae), and its predatory lady beetle Hippodamia variegata (Goeze) (Col.: Coccinellidae) was determined under laboratory conditions. The obtained data were analysed according to the age-stage, two-sex life table theory, the means, as well as the standard errors of all parameters, were estimated by the bootstrap procedure. Mean developmental time of immature stages (nymphal period) of the aphid on the resistant cultivar (15.20 days) was significantly higher than the susceptible one (9.53 days). The intrinsic rate of increase (r) of the rose aphid on the susceptible and resistant cultivars was 0.330 and 0.115 day-1, respectively. Furthermore, the values of the intrinsic rate of increase (r) of the predator fed on the aphids reared on the susceptible and resistant cultivars was 0.145 versus 0.126 day-1, respectively. The total pre-oviposition period (TPOP) of the lady beetle on the resistant cultivar (26.66 days) was significantly longer than that on the susceptible one (23.83 days), but total fecundity on the resistant cultivar (370.34 eggs/female) was significantly lower than that on the susceptible cultivar (451.65 eggs/female). According to obtained results, considering the lower intrinsic rate of increase (r) and fecundity of the predator on the resistant rose cultivar ('Tea'), more attention should be devoted for integrated control of rose aphids using resistant cultivars and predatory lady beetles.

Alder leaf beetle, Agelastica alni (Linnaeus, 1758) (Col.: Chrysomelidae) is an important pest of the alder trees in Iran. Both the beetle and its larvae feed on leaves of alder trees causing aesthetical and physiological damage. The toxicity of four commercial insect growth regulators (IGR) including lufenuron, flufenoxuron, hexaflumuron and pyriproxyfen was investigated on the second instar larvae (24 h old) of alder beetle, A. alni using the leaf dip method (for 30 s) under laboratory conditions [25 ± 1 ºC, 75 ± 5% RH and a photoperiod of 14:10 (L: D)]. The experiment was conducted in the toxicology laboratory of Guilan University. SPSS software was used for calculating LC50 values. 72 hours after treatment the insecticides proved to have high toxicity. In addition, these pesticides had negative effects on the morphology of larvae in the molting stage. LC50 values were estimated as 36.37 ppm for lufenuron, 48.35 ppm for flufenoxuron, 68.90 ppm for hexaflumuron and 54.37 ppm for pyriproxyfen, respectively. Abnormal morphological changes such as incomplete formation of the cuticle due to consumption of the pesticides by these larvae were observed. Considering that IGRs are safer to human and environment health, compared to conventional insecticides, these four IGRs especially lufenuron seems to be suitable candidates for development of IPM programs against alder leaf beetle.

The predatory mite Phytoseiulus persimilis Athias-Henriot has been used as importation from abroad or rearing in the laboratory and greenhouse in Iran. This predatory mite has been used for biological control of spider mites in greenhouses and fields. Due to the special thermal and humidity requirements of this mite, including temperature between 17-28˚C and relative humidity between 40-70%, the presence of this mite in natural conditions of Iran has not been reported so far. In the study of the fauna of mites associated with peanut in Astaneh-ye-Ashrafieh vicinity in Guilan province, a few specimens of this predatory mite were collected on peanut plants infected with the two spotted spider mites. After preparing microscopic slide and examining it under the microscope, the species of predator mite was identified as P. persimilis. This is the first report of the natural establishment of the predatory mite P. persimilis in Iran.