فصلنامه تحقیقات آفات گیاهی
سال دوازدهم شماره 4 (زمستان 1401)

In order to investigate on fauna of Corixidae family in Mazandaran and Golestan provinces, specimens were collected randomly by sweeping net and light trap in various freshwater habitats ranging from lakes, rivers, streams, paddy fields, and irrigation channels during 2021-2022. The specimens were identified using valid taxonomic identification keys. In this study, totally, six species were collected and identified. Species which are reported for the first time from Mazandaran and Golestan provinces are marked by an asterisk. Identified species are listed as follows:Corixa affinis Leach, 1817, Corixa punctata (Illiger, 1807)*, Hesperocorixa linnaei (Fieber, 1848)*, Sigara nigrolineata nigrolineata (Fieber, 1848)*, Sigara striata (Linnaeus, 1758) *, Sigara lateralis (Leach, 1817)An identification key was also provided for genera and species reported from these provinces.

In a three-year study, the population density and spatial dispersion of the common green lacewing, Chrysoperla carnea and its prey pests (Aphids, Thrips tabaci and Helicoverpa armigera) was investigated in apple orchards and tomato fields under two different conservational and conventional chemical managements, in Quchan, northeastern Iran. The chemical management pattern had a significant effect on the population density of the green lacewing, so that the highest density was observed in conservational pattern in both apple orchards and tomato fields (0.178 and 0.546 individuals/leaf or plant, respectively). The pattern of chemical management in apple orchards also changed the spatial dispersion of the green lacewing, so that its eggs and larvae population had random dispersion in conservational (with Taylor’s coefficients of 1.12 and 1.17, respectively) and aggregated dispersion in conventional (with Taylor’s coefficients of 1.42 and 1.29, respectively) orchards. While, the spatial dispersion of this predator was aggregated in both conventional and conservational patterns in tomato fields. In apple orchards, the increase in the green lacewing population after the implementation of conservational spraying could not prevent the increase in aphids’ population, so that their population increased significantly compared to the conventional pattern. In contrast, population density of the T. tabaci and H. armigera in tomato fields did not have much difference in conservational and conventional chemical patterns. Therefore, in tomato fields, it is recommended to replace the conservational spraying pattern with conventional spraying, but the conservational pattern should be used along with other complementary methods in apple orchards.

Phthorimaea operculella Zeller (Lep.: Gelechiidae), is one of the key pests of potato plants in fields and warehouses. This research was designed to determine interaction and the priority and delay of using two control factors including the parasitoid wasp, Trichogramma brassicae (Hym.: Trichogrammatidae) and UV-C radiation in controlling the egg stage of potato tuber moth (PTM), which has the least adverse effect on T. brassicae. The rate of oviposition and emergence of parasitoid on irradiated and control eggs was investigated. Also, ultraviolet rays were applied for 0, 8, 10, and 12 minutes on 1, 2, and 3-day-old eggs of PTM in two pre-parasitized conditions, and the second mode of irradiation was performed after parasitization, and the rate of parasitoid emergence was evaluated. The results showed that there was no significant difference between the two groups of eggs irradiated by UV-C rays and the control treatment. In UV-C irradiation on the parasitized PTM eggs, the percentage of parasitoid emergence decreased with the increase in the duration of irradiation, and in the case of irradiated-parasitized eggs, the rate of parasitoid emergence increased compared to the parasitized-irradiated eggs. The results of this study showed that 3-day-old eggs were more sensitive to ultraviolet rays than 1 and 2-day-old eggs. Also, the rate of emergence of parasitoid from irradiated-then-parasitized eggs increased compared to the parasitized-irradiated eggs. Therefore, in the simultaneous use of T. brassicae and UV-C radiation in controlling the egg stage of this pest and other target pests, first UV-C radiation and then release of T. brassicae is recommended.

Slugs are the most important pest of lettuce fields in the north of the country, and feed on different parts of lettuce plants, including leaves, stems, roots, and seeds, and destroy them. Currently, common chemical pesticides are used to control them. Nowadays, the use of non-chemical methods, such as attracting and catching slugs by trapping, in order to reduce the consumption of pesticides is necessary. In this regard, the efficiency of one type of commercial trap and two types of homemade traps with and without bait was compared against Deroceras agreste Linnaeus. The experiment was conducted in a completely randomized block design with eight treatments and four replications in 2019 and 2020 in field conditions. According to the results of simple and combined analysis of variance, among the treatments, green commercial trap with bait and green homemade box trap with bait (with total mean number of slugs captured, 76.5 and 75.6 in two years, respectively), had the highest attraction without significant difference from each other and the colorless plastic bottle trap (with total mean number of slugs captured, 29.8 in two years) had the least attraction. Also, green commercial with non-alcoholic beer bait and homemade green box trap with non-alcoholic beer with attracting and trapping the more slugs caused less damage to leaves (7.6 and 6.8 % in two years, respectively) and more yield (with means 13.1 and 11.5 kg/m2 in two years, respectively). The traps with bait compared the traps without bait and the green homemade box traps with bait compared with the cream box traps with bait were significantly more effective in attracting of slugs. Therefore, it is possible to use an inexpensive homemade green box trap with non-alcoholic beer, which has the same efficiency as commercial trap, to reduce the population and control slugs in lettuce fields.

The use of potassium fertilizer along with nitrogen fertilizer can be useful in recovering the damages of the rice plant during the attack of the stem borer, which ultimately leads to the reduction of the use of chemical insecticides in the paddy field. This research was carried out in the vegetative phase of the plant and the first generation of the pest on Hashemi cultivar rice. The following treatments were used for the experiment: T0=without the use of nitrogen and potassium fertilizer (control), T1=consumption of 46 kg of pure nitrogen per hectare with 50 kg of pure potassium oxide per hectare (100 kg of urea fertilizer+100 kg of fertilizer Potassium sulfate), T2=Consumption of 60 kg of pure nitrogen per hectare with 75 kg of pure potassium oxide per hectare (130 kg of urea fertilizer+150 kg of potassium sulfate fertilizer), T3=Consumption of 75 kg of nitrogen per 100 kg of nitrogen per hectare pure per hectare (163 kg of urea fertilizer+200 kg of potassium sulfate fertilizer) and T4=consumption of 90 kg of pure nitrogen per hectare with 125 kg of pure potassium oxide per hectare (195 kg of urea fertilizer+25 kg of sulfate fertilizer). The results showed that the most appropriate amount of fertilizer to compensate for the damage caused by the rice stem borer is the combination of nitrogen and potassium fertilizers, respectively 130 and 150 kg per hectare in two stages in the form of division and during the growth stage of the rice plant and in addition to compensation, it leads to an increase in its yield compared to the control treatment. Also, the regression relationship between dead hearts and rice crop yield due to fertilizer treatments during two years of research showed that with decreasing the percentage of dead hearts contamination in the first generation, crop yield in the treated treatments had an increasing trend. Therefore, success in stem borer management requires the development of optimal methods to compensate the damage and increase rice production.

Cultivation of diverse crops is a strategy key in sustainable agriculture. Increasing plant diversity in intercropping systems can be suitable for biological control of pests. In order to investigate the effect of mixed cultivation of sugar beet and red clover on the population of Aphis fabae Scopoli, natural enemies including Coccinella septempunctata Linnaeus, Hippodamia variegata Goeze, Orius niger Wolf, O. minutus Linnaeus, and Chrysoperla carnea Stephens, and some agricultural traits of sugar beet, an experiment was conducted in the form of completely randomized block design in four replications. Experimental treatments included monoculture of sugar beet (control) and seven types of strip cultivation systems including: 1) two rows of sugar beet  and four rows of red clover, 2) two rows of sugar beet and three rows of red clover, 3) one row of sugar beet and two rows of red clover, 4) two rows of sugar beet and two rows of red clover 5) three rows of sugar beet and two rows of red clover, 6) two rows of sugar beet and one row of red clover, 7) four rows of sugar beet and two rows of red clover. The results of this research showed that the different treatments of sugar beet and red clover intercropping on the aphid population, natural enemies, and agricultural traits including root yield, leaf yield, and shoot yield are significant at 1% probability level. The results of this research showed that the treatment of two rows of sugar beet and four rows of red clover can be useful in integrated pest management and biological control of A. fabae in sugar beet fields and improve agricultural traits.

Ants are eusocial insects of the family Formicidae and are one of the most successful insects in number and diversity. Despite their favorable impact on the ecosystem, they are sometimes regarded as serious pests due to damage to agricultural products and construction facilities. Baiting is a suitable alternative to many traditional ant control methods. In the present study, the effect of oral toxicity of fipronil, imidacloprid and borax on Tapinoma karavaievi workers was evaluated under laboratory conditions at 72, 96 and 120 hours after treatment and then the survival rate of workers treated with the LC50 of the studied compounds was compared in two weeks. According to the results, the highest oral toxicity in all three-time points was related to fipronil, imidacloprid and borax, respectively. In addition, the evaluation of the effect of pesticides on the survival of workers showed a faster control of workers treated with the LC50 of fipronil (2.46 mg ai L-1) compared to imidacloprid (32.61 mg ai L-1) and borax (2654.4 mg ai L-1). The results showed that 90% effectiveness of fipronil and imidacloprid occurred on days 7 and 11 after treatment, respectively, and it seems that 90% effectiveness of borax will probably take place in the third week after treatment. In general, the current study showed that all three studied pesticides have sufficient potential to control workers and the selection of the most suitable pesticide depends on considering the pesticide concentration, strategy of control and attention to the side effects of pesticides.