نشریه آفت کش ها در علوم گیاه پزشکی
سال دوم شماره 1 (بهار و تابستان 1394)

Spider mite is the most acaricide resistant pest of the greenhouses in the world. Improper acaricide management caused reduction in the effectiveness of the pesticide in a short period of time in a few greenhouses in the country. To increase the diversity and the impact of the acaricidal efficacy, an investigation was carried out to compare the efficacy of the new acaricide biofenzite (Floramite® SC 24%), at the doses of 0.3, 0.4 and 0.5 ml/1000L with the registered doses of hexythiazox (Nissorun® EC 10%), abamectin (Vertimec® EC 1.8%) and etoxazole (Baroque® SC 10%) respectively. Treatments included application of these acaricides against Tetranychus urticae infested strawberry, cucumber and rose plant leaves in Tehran and Esfahan provinces with a control (water spray). The complete randomized block design with three replications was used and with each replicate consisting of crops planted in 30 meter long rows. Samplings were done randomly at intervals of one day before and 3, 7, 14 days after spraying for strawberry and cucumber and this period extended up to 21 days for rose in Esfahan. The effect of each treatment was evaluated by counting the active mite stages on the lower side of 30 randomly collected leaves of strawberry, cucumber and roses. Percent mortality was calculated by Henderson- Tilton formula and statistical analysis was done with SAS software. Acaricidal treatments were compared with Duncan Multiple Rang Test Method. Results showed that all Floramite doses caused higher percent mortality (81.68-85.24%) up to 14 days on cucumber leaves. Maximum rose spider mite percent mortality was observed by 0.5 ml/1000L Floramite dose (61.14%) up to 21 days after treatment in Esfahan. The results show that, 0.4 and 0.5 ml/1000L of Floramite doses could be used in greenhouses with previous records of chemical control measures against spider mite infestation.

The soybean pod borer, Helicoverpa armigera (Lep.: Noctuidae) is the most important pest of soybean crop. Its larva feeds on young leaves, terminal and apical buds and pods of the crop and causes damage. In order to introduce new insecticides for chemical control of this pest, present experiment was carried out in a Randomized Complete Block Design with seven treatments in three replications in Mazandaran, Ardabil (Moghan) and Golestan provinces in 2011. The treatments included chlorfluazuron (Atabron® EC 5%), with three doses (500 ml/ha, 75 ml/ha and 1000 ml/ha) as a new insecticide, indoxacarb SC15 (250ml/ha), thiodicarb (1000g/ha), profenofos (2500ml/ha) and control (sprayed with plain water). Insecticide application was carried out when most of the pest eggs were hatched and very young larvae started feeding on the crop. Sampling and counting of the pest larvae were performed 1 day before and 3, 7, and 14 days after the treatments by randomly selecting 10 plants from four middle rows in each plot. Data were analyzed with SAS software, the means were compared using Duncan and the larval mortality was calculated by Henderson-Tilton formula. The results show that there is a significant difference in the percent efficacy among the treatments. The results of all three provinces are similar. The mean comparison of percent lethality based on Duncan test showed that the least larval lethality percentage occurred on the day three after the treatment. Mean comparison of percent efficacy of the tested pesticides in provinces of Ardabil, Mazandaran and Golestan showed that Chlorfluazuron (1000ml/ha) with 89.3%, 74.67%, and 60.05% and indoxacarb SC15 (250ml/ha) with 87.57%, 77.73% and 57.68% ranked first in the group. Chlorfluazuron, 750 ml/ha (83.69%, 60.87%, 35.86%), Chlorfluazuron, 500 ml/ha (75.42%, 53.1%, 40.93%), thiodicarb (75.69%, 45.33%, 34.81%) and profenofos (68.64%, 35.17%, 31.85%) were ranked in the next groups respectively. Chlorfluazuron (1000ml/ha) and Indoxacarb SC15 (250ml/ha) showed the highest efficacy against the larvae and therefore both of them could be recommended for the chemical control of H. armigera in soybean fields.

European corn borer, Ostrinia nobilalis (Hubner), is one of the most important pests of corn which causes economic losses annually. To compare the efficacy of some customary insecticides with new insecticides against the European corn borer current research was undertaken in a randomized complete block design with 9 treatments and in 3 replications. Treatments included eight insecticides namely Pyridalyl (EC 50%), spinosad (SC 24%), indoxacarb (EC 15%), deltamethrin (EC 2.5%), thiodicarb (DF 80%), Bt (Fanavar Zyst Mehr Asia Co.), Bt (S.A. Ctra. Madrid Co.), chlorpyriphos (EC 40%) and a check without spraying. Samplings were carried out one day before and 3, 7 and 14 days after spraying by counting the number of live larvae and bores on corn stems. The results show that spinosad with maximum efficacy (83.8%) was the best treatment against European corn borer. Pyridalyl, indoxacarb and thiodicarb were in second place with 67.15%, 66.23% and 64.93% efficacy, respectively, on both the generations. Mean comparison of number of bores on 10 plants showed minimum numbers in spinosad (6) and pyridalyl (10.33) treatments which are significantly different from deltamethrin (22) and chlorpyrifos (24) treatments. It is concluded that spinosad with maximum efficacy could be recommended to be used against European corn borer and pyridalyl, indoxacarb and thiodicarb could be in second rank. Moreover Bt with acceptable efficiency could be used in IPM programs of this pest.

The early blight disease of potato, Alternaria solani and A. alternata is an important fungal disease in potato growing areas in Iran. Thus, the chemical control experiments were conducted with iminoctadine tris (Belkute® WP 40%, Japan's Nippon soda Co.) at the rates of 500, 750 and 1000 g/ha, compared with other fungicides like trifloxystrobin (Flint® WG 50%) 2.5:10 , iprodione (Ruvral® WP 52.55, 1:1000), chlorothalonil (Daconil® WP 75%) 3:1000, mancozeb (WP 80%) 2:1000. The control was considered without any chemical application. The experiment was conducted in three growing regions of Rozveh, Damaneh and Chogha in Feraydan, Isfahan province on Agria, a susceptible potato variety. The disease index determination was by the extent of disease in six ranges 0, 10, 25, 50, 75 and 100, at the two growing stages, at and after flowering stages. The results show that, the Belkute fungicide at the rates of 1000 and 750 g/ha with 16.45 and 17.75 percent disease severity, effectively controlled the early blight disease respectively. The efficacy of Mancozeb at the rate of 1:1000 with 22.99% disease severity was significantlythe lowest in comparison with the other fungicides and the control with 32.95% severity. These results suggest that application of the Belkute fungicide at the rate of 750 g/ha could be recommended for the control of early blight disease of potato.

Melon aphid, Aphis gossypii Golver, is a key pest of greenhouse crops. In the recent years, attention has been paid to the biological control of this pest. The most important natural enemy of this pest is the parasitoid wasp, Aphidius colemani Viereck. In this study, lethal and sublethal effects of imidacloprid (SC 350) applied by two different application methods (irrigation and foliar spraying) were assessed against this parasitoid at three doses (field dose, half of the field dose and one and half times the field dose) in a randomized complete block design with four replications. Due to high mortality rates, bioassay tests on adults were performed using contact method. The LC50 and LC25 values were estimated as 0.028 and 0.012 g ai/l for adults, respectively. The foliar spraying of Imidacloprid at concentrations of 350, 700 and 1000 ppm caused 95, 100 and 100 percent mortality of the adult parasitoids, respectively. Ten percent mortality was observed when these concentrations were applied by the irrigation method. According to IOBC classification imidacloprid was grouped in the slightly-harmful category. Based on the present results, the adult parasitoid showed high susceptibility to imidacloprid; therefore, imidacloprid should not be applied when the population density of this parasitoid is high in the greenhouse.

The cutworms (Agrotis spp.) are cosmopolitan polyphagous pests and cause damage to a variety of crops including chickpea. In this study, the efficacies of some safe insecticides on chickpea cutworms, Agrotis segetum (Denis and Schiff.) were examined. The experiments were carried out in randomized complete block design with 6 treatments in 4 replications. The insectiside treatments included spraying with: tebufenozide (Mimic® SC 20%) at the rates of 0.75 and 0.5L/ha, fipronil hexaflumuron (EC 5%) at the rate of 1 L/ha, emamectin benzoate (Emamectin® SG 5%) at the rate of 200 g/ha, indoxacarb (Avaunt® EC 15%) at the rate of 0.25 L/ha and the control treatment. The results in both Markazi and Kurdestan provinces based on the number of damaged plants and total production, show significant differences among the treatments at level of 1%. Tebufenozide (Mimic® SC20%, 0.75 L/ha) with 5.75±0.85 and 5.67±0.48 damaged plants and the yield equivalent of 401.525±8.25 and 415.65±9.07 kg/h respectively, was the most effective insecticide and Indoxacarb (Avaunt® EC15%) with 23.75 ± 2.86 and 24.25 ± 2.56 damaged plants and 279.15 ± 4.02 and 300.25 ± 3.89 kg/h a yield, respectively showed maximum loss and minimum product after the control. Therefore tebufenozide is recommended for the control of cutworms on chickpea.

Two-spotted spider mite (Tetranychus urticae Koch.) is an important pest on common bean in Iran which causes quantitative and qualitative damages to legumes. Its activity on the backside of host leaves reduces the efficiency of sprayer machines. In this research, efficiency of six sprayer machines using two concentrations of hexythiazox (Nissorun®, 0.5 and 0.3 L/ha) were studied. The experimental design was a factorial test conducted based on the completely randomized block design with 14 treatments in 3 replications. The sprayers included wheelbarrow sprayer 100 liters), atomizer sprayer with simple head, atomizer sprayer with electrostatic head, atomizer sprayer with micronair head, micronair sprayer with tail boom and knapsack sprayer. Sampling of T. urticae population was performed one day before and 1, 3, 5, 7, 14, 21 and 28 days after spraying. The results show that the highest and the lowest efficiency percentages are 83.74 and 23.46% for electrostatic sprayer and micronair sprayer with tail boom, respectively. Also, the efficiency percentages for other sprayers measured are 76.50%, 57.41%, 43.22%, and 36.81 for wheelbarrow sprayer, atomizer sprayer with micronair head, atomizer sprayer with simple head and knapsack sprayer, respectively. The amount of solution used in the electrostatic sprayer, atomizer sprayer with micronair head and micronair sprayer with tail boom were 42.69, 134.4 and 56.25 l/ha, respectively, which indicates decrease in the consumption as compared with the others. Hence, the electrostatic sprayer is recommended as the most effective sprayer for the control of Two-spotted spider mite in the bean fields.