جستجوی مقالات مرتبط با کلیدواژه « spirotetramat » در نشریات گروه « گیاهپزشکی »

The cotton whitefly Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae) is one of the important pests of agricultural products that causes great economic losses. In this research, the effect of spirotetramat on three different developmental stages of the pest was studied in several populations that were collected from different provinces of Iran. Bioassay was done by leaf disk method. The results showed a higher sensitivity of the 2nd nymph stage compared to the adult stage and the egg stage; while the adult stage showed the least sensitivity to spirotetramat. The highest rate of resistance in different developmental stages was observed in the Jiroft population The LC50 ratios of adults in Karaj, Yazd, Pishwa, and Jiroft populations to sensitive one (Marand) were 7.6, 6.2, 4.2, and 9.6, respectively. For second instar nymphs, the ratios were 2.0, 2.2, 2.1, and 5.5 respectively. The investigation on detoxification enzymes indicated the higher activity of monooxygenase enzyme in the resistant population of Jiroft (3.34-fold) compared to the Marand population, which indicates the effective role of these enzymes in creating resistance. According to the results, to prevent resistance development, it is necessary to use other chemical compounds with different modes of action to prevent the occurrence of cross-resistance while affecting different developmental stages of pests.

Wheat is the most important strategic crop in Iran and the world. Sunn pest Eurygaster integriceps Puton (Hemiptera: Scutelleridae) causes a lot of damage annually. Currently, two groups of IRAC insecticides including pyrethroids and organic phosphorus compounds are recommended against this pest in Iran and other countries infested with the Sunn pest. In this research, different insecticides were selected from the eight insecticide groups of IRAC, and contact bioassay was carried out on two life stages of the Sunn pest. The results showed that among the tested insecticides, Deltamethrin (LC50=2.93 mg a.i./L) as a pyrethroid group, had the most contact toxicity among chemical compounds against overwintered adults of the Sunn pest, and Fenitrothion as an organic phosphorus compound  (LC50=19.4 mg a.i./L) was ranked in the second group. But on the new generation of the Sunn pest, both insecticides were ranked in the same group at 72 hours after exposure (LC50=4-4.6 mg a.i./L). Further investigations revealed that among neonicotinoid insecticides, Thiamethoxam had more contact toxicity and ranked in the next group. Mortality comparison of different insecticides in high concentration (60-20000mg/L) based on commercial formulations showed that Deltamethrin and Fenitrothion insecticides caused 90-100% mortality in both life stages of the Sunn pest. The new insecticides, Spirotetramat, Flonicamid, and Chlorantraniliprole did not show acceptable effectiveness 72 hours after exposure on overwintered and new-generation adults (3.3-43%). Therefore, most of the new insecticides tested for the chemical control of the overwintered and the new generation adults did not have acceptable mortality, and only thiamethoxam insecticide can be studied on Sunn pests in field conditions.

The common pistachio psyllid, Agonoscena pistaciae is a key pest of pistachio trees in Iran. Both adults and nymphs cause great economic damages by sucking sap and produce large amounts of honeydew. The continued use of pesticides to control A. pistaciae leads to resistant of its populations to several pesticides and inefficiencies in biological control, resulting in pest outbreaks.  In the present study, Field experiments were conducted during 2019–2020 on pistachio trees, the Ahmad Aghaei cultivar, in Kerman, Yazd, Qom, Khorasan Razavi, Khorasan Shomali, Khorasan Jonoubi, Semnan, Fars, Markazi, and Esfahan provinces to evaluate the effect of DG oil on A. pistaciae in comparison with the two pesticides Spirotetramat and Dinotefuran. The sampling was carried out a day before spraying and 1, 3, 7, 14, 21 and 28 days post-treatment. The experiments were conducted based on complete randomized blocks with four treatments (included the recommended dosage of DG oil (0.5 liter1000 liter water/ha), Spirotetramat (1 liter/1000 liter water/ha), Dinotefuran (0.75 kg/ 1000 liter water/ha and control (Spraying with water) and four replications. Results showed a high performance of DG oil starting from the first day after spraying and Continued for four weeks. Compared to Spirotetramat and Dinotofuran, DG oil had a suitable and satisfied performance. DG oil is recommended as the most environment-friendly and IPM compatible compound to control A. pistaciae.

The apple armored scale, Lepidosaphes malicola Borchsenius (Hem.: Diaspididae) an important pest of fruit trees. Control of this pest depends mostly on the use of chemical pesticides. To study the effect of several pesticides on the pest population, two separate experiments were conducted in a randomized complete block design with three replications in two orchards. The first factor was treatments [control (water), spirotetramat 0.5 and 0.75 ml/L, flupyradifurone, thiacloprid, and pyriproxyfen 0.5 ml/L]. The second factor was the sampling time (1 day before and 1, 3. 5, 7, 14, 21, 28 and 35 days after treatment). Spirotetramat and flupyradifurone (with more than 80 percent mortality) had the most effect on the nymphal mortality. The mortality in thiacloprid and pyriproxyfen was lower than that of spirotetramat and flupyradifurone. By considering the treatment time, the mortality rate of nymphs by flupyradifurone, a butenolide with knockdown effect reached its highest level one day after treatment. In 0.75 ml/L concentrations of spirotetramat the highest decrease in the nymphal population was observed one week after treatment. Spirotetramat with up and down bilateral movement ability is a very long-lasting systemic insecticide. Results indicated a negligible effect of the pesticides on adult mortality under female shields. The use of 1.5- 2 percent volck® oil in winter spraying had a significant effect on pest control. Overall, spirotetramat and flupyradifurone showed a significant effect on the nymph’s control and can be recommended.

Chemical control is the most commonly practice in controlling pests. The application of chemical control is recommended in combination with other reduced risks control techniques such as biological control under Integrated Pest Management programs. Therefore, finding the appropriate chemical insecticide and the right time of spraying seems essential. In this study,three different growth stages of Trichogramma evanescens Westwood (Hymenoptera: Trichogrammatidae) including larvae, pre-pupae, and pupae were exposed to the field recommended concentration of deltamethrin, Spirotetramat and flupyradifurone insecticides using insect dipping method. After which, the reproductive, biological characteristics and life table parameters of T. evanescens female adults were estimated. The eggs treated with deltamethrin in all three developmental stage of T. evanescens significantly reduced fecundity rate and oviposition period of the female adult parasitoids. Thegross reproductive rate (GRR), finite rate of increase (λ), intrinsic rates of increase (r), and net reproductive rate (R0) were not affected when larval and pre-pupal stages of T. evanescens were exposed to field recommended concentration of spirotetramat and flupyradifurone in comparison with control. However, the pupal stage showed to be the most susceptible stage and all of the life table parameters were affected upon exposure to three insecticides. Results of this research suggest a relative compatibility of spirotetramat and flupyradifurone with T. evanescens parasitoid. However, experiments under field conditions to evaluate the impact of tested insecticides on T. evanescens are required to confirm the results.

Background and Objectives:

 Water pH is one of the most important factors that affects the inefficiency of insecticides against the common pistachio psyllid, Agonoscena pistaciae Burckardt and Lauterer (Hemiptera: Aphalaridae), as the most important pest in Iran's pistachio orchards.

 Materials and Methods:

 In this study, the effect of insecticides including spirotetramat (Monvento® SC 10%) and imidacloprid (Confidor® SC 35%) and pH reducing agents, such as Rectiphier® and Citral pH®, on the reduction of population density of eggs and nymphs of common pistachio psyllid were investigated under field conditions. The experiment was carried out as randomized complete block design with four replications. The samplings were done one day before and 3, 7, 14, 21 and 28 days after spraying.

 Results:

 The results indicated that adding Rectiphier and Citral pH to the insecticides had no significant effect on increasing the efficacy of spirotetramat and imidacloprid on eggs population of pistachio psyllid, and only on 7 days after spraying, adding of Rectiphier to imidacloprid significantly increased the efficiency of the insecticide, and reduced the amount of oviposition of A. pistaciae (91.58%). The results of the effect of different treatments on nymphs population density of A. pistaciae showed that the effect of insecticides + pH reducing agents was more than application of insecticides alone, but their effect was not significant, and only on 3 and 7 days after spraying, Rectiphier significantly increased the effect of imidacloprid. The reduction of nymphal population densities in imidacloprid + Rectiphier treatment were 90.13% and 93.23%, on those sampling dates, respectively. 

Discussion:

PH reducers (Rectifier and Citral pH) could have the potential to increase the efficacy of spirotetramate and imidacloprid or other insecticides to control A. pistaciae and produce healthy crops, reduce costs, environmental hazards and side-effects on natural enemies and to minimize application of chemical insecticides. However, more research is needed with regard to the effect of different compounds of pH reducer, different concentrations of those compounds and also the effect of these compounds on different water pH. 

The two-spotted spider mite Tetranychus urticae Koch(Acari: Tetranychidae) is one of the most important and destructive herbivorous mites in fields and greenhouses, and its control is very important due to the wide range of its hosts.

The sublethal effects of spirotetramat based on leaf dipping method were evaluated on demographic parameters of two-spotted spider mite in the laboratory conditions of 25±1 ºC ,60±5% RH and a photoperiod 16:8 hours (L:D). The obtained data were analyzed based on age-stage two sex life table theory.

All sublethal concentrations caused a significant decrease in oviposition period, total fecundity, longevity and total life span compared to control. Maximum and minimum means of longevity of male and female mite were observed in untreated and LC35 groups. Total fecundity varied from 18.12 (offspring/individual) in treatment with 35% sublethal to 57.71(offspring/individual) in control. The lowest net reproductive rate (R0 (was estimated at 11.95 (offspring/individual) at the highest experimental dose. The intrinsic rate of population increase (rm) was recorded as 0.22 offspring/individual/day in control and 0.17 offspring/individual/day in LC35 treatments, respectively. Mean generation time (T) was not significantly affected by different tested doses.

The results of this study demonstrated that sublethal dosage (LC35) of spirotetramat was effective against two-spotted spider mites

The efficiency of plant extracts of Rubia tinctorum L. (Rubiaceae) and Ferula gummosa Boiss(Apiaceae) and release of the mirid bug Nesidiocoris tenuis Reuter (Miridae) were compared with Espirotermat to control sweet potato whitefly, Bemisia tabaci Genn. (Hem: Aleyrodidae) in semi-field conditions. LC50 of plant extracts and pesticide for sweet potato whitefly was calculated. In the main experiment, plant extracts and pesticides were sprayed on tomato plants in cages covered with mesh fabric. LC50 values of pesticides and plant extracts were sprayed on plants. Nymph of mirids was hanged to plant tomatoes. Subsequent days after treatment, number of sweet potato whitefly was counted. The experiments were carried out at 25 ±5 °C, 50±5 RH and photoperiod of 16:8 h (L:D). LC50 of R. tinctorum and F. gummosa extracts as well as Espirotermat was 22.359, 45.641 and 0.404 mg/ml, respectively. Post density decreased R. tinctorum and F. gummosa extracts, Spirotermat and the mird bug 86.54, 83.73, 89.16 and 87.67 percent pf egg stage, 80.20, 76.28, 82.56 and 79.38 percent of nymphal stage, 80.66, 75.26, 85.89 and 81.86 percent of total immature stages as well as 81.89, 79.49, 84.85 and 81.98 of total nymphal stages. Findings from experiments could be promising for further studies on plant extract of Rubia tinctorum and the mirid bug as on alternative to chemical pesticides in natural conditions.

Common pistachio psylla, Agonoscena pistaciae, is the most important pest of pistachio orchards in Iran and reduce the quantity and quality of the product. In this study, the effects of Flupyradifurone 0.5, 0.75 and 1 ml L-1, Spirotetramat and Thiacloprid 0.5 ml L-1 and Flupyradifurone (0.5 ml L-1) with irrigation water were evaluated on nymphs and adult stages of A. pistaciae in Niriz region of Fars province. The number of nymphs and adult of A. pistaciae recorded in one day before until 3, 7, 10, 15, 20, 25, 30 and 40 days after chemical applications. The results showed that 3 days after treatment, different concentrations of Flupyradifurone and Thiacloprid have a good effect on the psyllid nymphs and the mean maximum of dead nymphs was in Thiacloprid. The mortality in Spirotetramat treatment on nymphs was increased in on the day 7 and the highest mortality occurred after 20 days. The mean number of the nymphs on treated trees with Flupyradifurone and Thiacloprid increased after 15 days of treatment. Efficacy of Spirotetramat increased after 7th day and the maximum efficacywas 99.44 percent on 20th day after treatment. The highest mean number of adult psyllid mortality was observed on day 3 after treatment in Flupyradifurone with concentration of 1 ml L-1. The efficacy of Spirotetramat on adults increased after 10 days post-treatment and the highest was occurred on 30 day of sampling (98.23). The results showed that Spirotetramat was effective in decreasing of the pistachio psylla population after 40 days of the insecticide application.