فصلنامه تحقیقات آفات گیاهی
سال چهاردهم شماره 1 (بهار 1403)

Tea mealybug, Pseudococcus viburni (Signoret) is one of the important pests of tea and citrus orchards in Northern provinces of Iran. In the current study, the effect of several plant-based insecticides and microemulsion formulaion of Sophora pachycarpa leaf and root extract were investigated against tea mealybug under laboratory conditions by leaf dip method. The LC50 values of matrine, pepper extract, cinnamon and garlic essential oil, neem oil, coconut oil soap, castor oil, formulated leaf and root extracts of S. pachycarpa, and espiromesifen were determined as 2157, 1538, 2825, 5608, 4746, 6585, 4493, 5357 and 2676 mg formulated/l on adult of the tea mealybug, respectively. In addition, the LC50 of aforementioned compounds was calculated as 2188, 1555, 2809, 5559, 4703, 5842, 3457, 5195 and 1856mg formulated/l for third instar nymph of this insect, respectively. The bioassays showed that pepper extract, matrine, and cinnamon and garlic essential oil were most efficient treatments against tea mealybug. Treatments of third instar nymphs by the insecticides also affected the activity of detoxifying enzymes including alpha- and beta-esterases, acetylcholinesterase, glutathione S-transferase (GST) and MFO system. Pepper extract, cinnamon and garlic essential oil, and formulated leaf extract of S. pachycarpa decreased the activities of α-esterase. Since the pepper extract, matrine, cinnamon and garlic essential oil showed significant mortality against nymphs and adults of the tea mealybug these insecticides can be considered in the integrated management of the tea mealybug.

The flour beetle (Tribolium confusum du Val) is one of the most important coleopteran pests on stored products, especially cereal grains and flour. Frequent application of chemical pesticides in insect pest management has resulted in numerous side effects such as environmental contamination, threat to human health and non-target organisms, and the development of pest resistance. In the present study, the fumigant toxicity and anti-nutritional effects of rosemary essential oil on flour beetle adults were investigated. Due to the relationship between the chemical compositions of essential oils with their biological effects, the compounds of rosemary essential oil were studied by gas chromatography-mass spectrometry. Rosemary essential oil was rich in terpenic compounds, including the hydrocarbon monoterpenes (28.72%), monoterpenoids (57.03%), hydrocarbon sesquiterpenes (3.09%), and sesquiterpenoids (3.25%). The concentration of 73.5 µl/l air of essential oil caused 90.0% mortality of the pest after 24 h, which was increased to 100% by 48 h. The use of 24-h LC40 and LC50 values of essential oil, respectively equal to 26.7 and 35.5 µl/l air, reduces the nutritional indices of the pest, including consumption index, relative consumption rate, and relative growth rate after 5 and 10 days. In addition, the feeding deterrence index of the mentioned values was estimated at 40.7 and 45.9% after 5 days and 53.4 and 59.5% after 10 days, respectively. Therefore, rosemary essential oil can be introduced as one of the available and efficient agents in the management of flour beetle for further research.

During 2023, samples of leaves and branches of lilac persimmon (Diospyros lotus L.) infested with broad mites (Tarsonemidae) were collected from Rasht city, Guilan province. After preparation of microscopic slide from mite specimens, they were identified using reliable taxonomic references. Polyphagotarsonemus latus (Banks, 1904) was identified for the first time from Guilan province on lilac persimmon. The damage symptoms of this pest mite were observed in the form of deformity, curling, darkness, and thickening of leaves and deformity of branches and buds. The damage of this pest is severe on the branches and young leaves. This is the first report of the presence of yellow broad mite (Polyphagotarsonemus latus) on lilac persimmon in Iran. The following predator mites were also collected and identified in association with this pest mite on lilac persimmon.
Mesostigmata, Phytoseiidae: Euseius stipulatus (Athias–Henriot, 1960), Neoseiulus barkeri Hughes, 1948, Phytoseius plumifer (Canestrini & Fanzago, 1876), Transeius wainsteini (Gomelauri, 1968); Prostigmata, Cunaxidae: Lupaeus martini (Den Heyer, 1981); Trombidiidae:  Allothrombium pulvinum Ewing, 1917.

Using microcapsulation in formulation of biological agents such as antagositic bacteria plays an important role in increasing the efficiency and stability of these agents in the adverse environmental conditions. In the present study, the effect of encapsulation of Pseudomonas fluorescens VUPF5 bacteria with alginate-whey protein and silica and zinc oxide nanoparticles was investigated on some important elements of the tomato plant, the number of eggs, oviposition period and the Longevity of the tomato moth Tuta absoluta Meyrick (Lepidoptera: Gelechidae). Greenhouse experiments were carried out at 27±2 °C, relative humidity of 60±5% and photoperiod of 16:8 h light:dark. The amount of some importatnt nutrients in tomato plant were measured in four treatments including: 1) plant treated with capsulated bacteria, 2) plant treated with zinc oxide + silica nanoparticles, 3) plant treated with uncoated bacteria, and 4) plant treated with water + alginate + whey protein (control). The results indicated that treatment of the plants with the capsulated bacteria caused an increase of  10.2, 13.8 and 1.6 times the amount of phosphorus, potassium and iron elements respectively compared to control plants, Moreover, length of the adult pre-oviposition period (APOP), the total pre-oviposition period (TPOP), and the Longevity were longer in the insects were fed on the plants treated with the capsulated bacteria. But, the number of eggs were fewer compared with insects fed on the control plants. The results showed that the bacteria improved plant growth and increased its resistance against T. absoluta.

Cold storage is a valuable technique for extending the survival time of parasitoid wasps, but it may have a detrimental impact on their survival and successful oviposition. In this study, we investigated the effect of cold storage of the larval and pupal stages of Aenasius bambawalei at 4°C for two and four weeks on their post-storage developmental time, adult emergence and longevity, female sex ratio, and morphometric characteristics. The highest emergence rate (72%) was observed in pupae after two weeks of cold treatment. In females, the shortest (8.40 days) and the longest (11.40 days) developmental time were seen in pupae and larvae exposed to two weeks of cold treatment, respectively. This trend was also similar in males, and the pupae and larvae subjected to two weeks of cold treatment showed the shortest (10 days) and the longest (11.8 days) developmental period, respectively. The sex ratio and adult longevity decreased significantly with the increase of immature stages’ cold storage period. Additionally, the length of the hind tibia and antennae decreased compared to the control. Based on these findings, we recommend two weeks of A. bambawalei pupae cold storage to increase the survival time of the parasitoid, as cold storage of larvae as well as long period cold storage of pupae, may have negative effects on the adult's fitness.

The purpose of the current research is treatment of cotton seeds with appropriate pesticides and foliar application with plant compounds in a way that be effective in control of first-season sap sucking pests in cotton fields. This experiment was designed to study the effect of several treatments including: 1-seed treatment with Thiamethoxam (Cruiser®), 2-seed treatment with Thiodicarb (Larvin®), 3-seed treatment with Imidacloprid (Gaucho®), 4-foliar application of insecticidal soap containing coconut oil (Palizin®), 5-foliar application of botanical insecticide containing pepper extract (Tondexir®), 6-foliar application of imidacloprid (Confidor®), and 7-control for control of first-season sap sucking pests in cotton fields. This research was carried out in a randomized complete block design with five replications at Darab Agricultural Research Station during two years (2020 and 2021). Seed treatments with Larvin® and Gaucho® were applied only in the second year of experiment. The results of the first year of the experiment showed that the cotton seed treatment with Cruser® kept the cotton seedlings free from the cotton aphid (Aphis gossypii Glover) until one month after the sowing date compared to other treatments that were applied as foliar spraying. The results of statistical analysis 41 days after sowing date showed that the most effective control method of onion thrips (Thrips tabaci Lindeman) is seed treatment with Cruiser®. The results of the second year of the experiment showed that Cruzer®, Larvin®, and Gaucho®, which were impregnated with cotton seeds, caused a significant decrease in the population density of cotton whitefly nymph [Bemisia tabaci (Gennadius)] until the end of the sampling period (41 days after sowing date). Foliar spraying of seedlings with herbal compounds (Palizin® and Tondexir®) in both years initially had a significant effect on reducing the population of aphids and whiteflies, but with increase of the time, their effect was less than other treatments. Based on the results of the present research, seed treatment with Cruzer® not only offers more control against cotton seedling sucking pests (onion thrips, cotton aphid and cotton whitefly), but also can be a better option in terms of economy, user's health and environmental effects.

In the present study, the effects of different supplementary ingredients on blastospore production of entomopathogenic fungus Beauveria bassiana (Bals.) Vuill. Strain IRAN 1395C were evaluated. In the first step, effects of extracts of different agricultural products including rice bran, wheat bran, barley bran, maize bran, and potato waste on blastospore production were evaluated. Our findings revealed that the medium containing rice bran extract provides the best conditions for sporulation. Then, different supplementary proteins including whey, soybean, and egg white with a concentration of 4% were added into the rice bran medium, and their effects on blastospore production were investigated. Different proteins had no positive effects on sporulation. In the last step, effects of adding different chloride salts (KCl, MgCl2, and CaCl2) to the selected culture medium on the increase of blastospore production was studied. The results obtained indicated that use of calcium chloride (CaCl2) had the highest effectiveness on blastospore production than other salts tested. Finally, the pathogenicity of blastospores obtained from liquid medium and conidia harvested from solid culture was compared on Tetranychus urticae Koch. The bioassay output revealed no statistical differences between the pathogenicity of blastospore obtained in liquid medium (LC50 = 3.29 × 106 Blastospore/ml) with conidium produced in solid medium (LC50 = 3.23 × 106 Conidium/ml). The present findings revealed that liquid media could be so helpful for developing mass rearing programs of B. bassiana.