فصلنامه تحقیقات آفات گیاهی
سال سیزدهم شماره 4 (زمستان 1402)

In this research, the efficiency of the parasitoid wasp, Habrobracon hebetor (Say) in integrated with Matrine and Bacillus thuringiensis (Berliner) subsp. Kurstaki (Btk) against Anagasta kuehniella (Zeller), was investigated. Lethal and sublethal concentrations (LC30) of Matrine and Btk were determined by bioassay method on host larvae. To evaluate the preference of the host larval instars by the parasitoid, different larval instars were provided for parasitoid and the rate of parasitism was determined. The fourth and the fifth instar larvae of the host were treated with sublethal concentrations of Matrine and Btk then were provided for parasitoid in choice and non- choice conditions. The rate of paralysis, parasitism, egg-laying, emergence percentage and sex ratio of release wasps were determined. The results showed that female parasitoid preferred the fourth and fifth instar larvae of the host for parasitism. In the choice test, Matrine-treated larvae were more preferred by female parasitoid while in non-choice test, the highest amount of parasitism and egg-laying was related to the control treatment. The emergence percentage of adult wasps and their sex ratio (Female/Total), obtained from Matrine-treated fourth and fifth instar larvae, were 61 and 54% in the choice and 61 and 54% in the non-choice tests. The results showed that Matrine and Btk have significant potential in controlling of A. kuehniella. However, due to the sublethal adverse effects of these control agents on the efficiency of the parasitoid, simultaneous use of them with the parasitoid wasp, H. hebetor is not recommended.

Cabbage aphid, Brevicoryne brassicae L., is one of the most important pests of cruciferous crops worldwide. In the present study, the lethal (LC50) and sublethal (LC25) effects of Clothianidin and summer oil were investigated on biological properties and population growth rate parameters of cabbage aphid under greenhouse conditions. The leaf dipping method containing aphid adults was used for bioassays. The life table data were analyzed based on the age-stage, two-sex life table theory. Results indicated that Clothianidin affected the population growth rate of aphids by prolongation of the pre-adult stages, decreasing survival rate, adult longevity, and reproduction in comparison to summer oil. The lowest fecundity rate (14.14 nymphs per female) was recorded in Clothianidin treatment. The lowest and highest intrinsic rate of increase (r) was observed in Clothianidin (0.2123 day-1) and control (0.3636 day-1), respectively. The results also demonstrated that population growth of the cabbage aphid in different treatments was exactly in consistent with the estimated population growth parameters. For example, aphids treated with Clothianidin, had slower growth rate and, thereby prolonged mean generation time (T). The overall results demonstrated that Clothianidin could be considered as an effective insecticide in the management of cabbage aphid.

The tomato leaf miner, Tuta absoluta (Meyrick), is one of the important pests of tomato in Iran. In the present study, the lethal and sublethal effects of the insecticide alpha-cypermethrin + teflubenzuron by leaf dipping method were investigated against the second-instar larvae of the tomato leafminer on Early Urbana Y and Super strain B tomato cultivars. The results showed that the toxicity of alpha-cypermethrin + teflubenzuron to tomato leafminer larvae in the Early Urbana Y variety (LC50 = 4509 ppm) is more than its toxicity in the Super strain B (LC50 = 5595 ppm). Treatment with alpha-cypermethrin + teflubenzuron increased the larval and pupal periods and developmental time of the tomato leafminer in the Early Urbana Y compared to the Super Strain B and control group. The lowest longevity and fecundity of the tomato leafminer were observed in the Early Urbana Y. The life-table parameters of the pest, including intrinsic rate of increase (r) and finite rate of increase (λ), on the Early Urbana Y treated by alpha-cypermethrin + teflubenzuron (0.0479 and 1.0491 day-1, respectively) were significantly lower than corresponding amounts on the treated Super Strain B (0.0684 and 1.0708 day-1, respectively). Treatment with alpha-cypermethrin + teflubenzuron increased the mean duration of a generation (T) of pest compared to the control. The results of the present study indicated that the use of alpha-cypermethrin + teflubenzuron on the Early Urbana Y variety in the management of T. absoluta could be more effective than the Super strain B variety.

Leopard moth, Zeuzera pyrina L. is an important woodborer in orchards especially on walnut trees. Its damage has been remarkably increased in Urmia region in recent years. In this research, the amount of pest damage was compared on different orchards such as apple, walnut and peach. The best control method of pest was investigated by using of two insecticides, pheromone and light traps in field conditions. The highest pest damage was observed on walnut trees in Balo village and the least damage was recorded in Gajin and Haji-Abad villages. Old walnut trees (25-30 years old) suffered more damages than younger trees. In 2020, peak of adult leopard moth emergence was recorded in May 29 by using pheromone trap via mass trapping. Two weeks after flight peak, control methods including the use of Hexaflumuron and Imidacloprid insecticides along with pheromone and light traps were assessed. Based on the obtained results, Hexaflumuron along with the pheromone trap exhibited the best efficacy considering the reduced pest damage in 2021. Thus, this method can be used effectively in integrated management program of leopard moth.

Seasonal population dynamics of the aphids on two important commercial citrus species, Thomson navel orange (TNO) and Satsuma mandarin (SM) were investigated in the west of Mazandaran province, Ramsar, during 2015-2016. Samplings were performed biweekly from April 2015 to July 2016. In each sampling date, four young shoots were randomly selected from each main geographical direction of each tree and the number of aphids was counted under a stereomicroscope. The Pearson correlation coefficient was used to determine the relationship between aphid density and temperature and relative humidity as variables. For both species of citrus, the results showed that the first and second population peaks of the aphids occurred in May and October, respectively. Furthermore, there was a significant difference between the infestations of both citrus host plants by the aphids, with Satsuma mandarin showing more infestation. There was a significant difference among the population densities of different aphid species on both citrus species. Aphis spiraecola, Aphis gossypii, and Toxoptera aurantii had the highest population abundances, respectively. A positive and significant correlation was observed between these citrus aphid population densities and temperature (r= 0.689, n=49, P=0.04), however, the correlation was not significant for relative humidity (r= 0.661, n=49, P=0.53). In total, seasonal population dynamics of the citrus aphids were affected by the host plant species and different species showed different population fluctuation trends.

The cotton mealybug, Phenacoccus solenopsis Tinsley, is a potential pest that threatens green landscape in Ahvaz. In this study, the short-term and long-term effects of various insecticides (imidacloprid, diazinon, spinosad, Palizin®, and azadirachtin) on the populations of cotton mealybugs and predatory ladybird beetles, Nephus sp. and Hyperaspis sp., as well as on the parasitism rate of cotton mealybug by Aenasius bambawalei Hayat, were investigated under field conditions. The results of the bioassay at 24 h after treatment showed that imidacloprid (84.6%), diazinon (84.1%), and Palizin® (77.4%) significantly reduced the population of mealybugs compared to the control. The decrease effect of azadirachtin on the population density of cotton mealybugs 24 h after treatment was not significant (38.1% compared to the control). Furthermore, diazinin and azadirachtin had the greatest negative impacts (100% reduction compared to the control), and Palizin® had the least toxicity to ladybirds, with no significant difference compared to the control treatment. The long-term effects of the tested insecticides showed that, compared with the other treatments, imidacloprid and Palizin® had significant effects on reducing the pest population. Palizin® and azadirachtin had the least effect on the parasitism activity of Aenasius bambawalei. Both imidacloprid and insecticidal soap were more effective at reducing the P. solenopsis population than were the other treatments, but due to the greater negative effect of imidacloprid than of insecticidal soap on natural enemies and the limitation of using insecticides in green landspaces, insecticide soap is suggested for use in IPM programs for this pest.

In 2023, from samples of branches and leaves of yew tree, Taxus baccata L. (Taxaceae), a beetle belonging to the family Ptiliidae was collected and identified in Rahim Abad, Rudsar city, Guilan Province, Northern Iran. After correspondence with expert’s specialists of the family Ptiliidae, the species of the collected beetle was determined as Acrotrichis montandonii (Allibert, 1844) (Coleoptera: Ptiliidae). This is the first report of A. montandonii from Iran.