نشریه آفت کش ها در علوم گیاه پزشکی
سال دوم شماره 2 (پاییز و زمستان 1394)

The goal of this investigation was to study the effectivenessy of different acaricides on the control of twospotted spider mite (TSSM) at different mite population densities. Study was conducted based on the randomized complete block design (RCBD) using split plot experiment. When the pest population exceeded 3, 5 and 7 mites on the abaxial surface of each leaf in the main plot, spraying was done by sub plot treatments including: fenazaquin (Pride® SC 20%) at the rate of 0.5 lit/ha, fenpyroximate (Ortus® SC 5%) at the rate of 0.5 lit/ha, bromopropylate (Neoron® EC 25%) at the rate of 2 lit/ha and only water as control. Sampling was done 1 day before, 3, 7 and 14 days after each spraying. For sampling, 30 leaves were selected randomly from each treatment and the number of mites (adults & nymphs) was counted at 2 cm² area of under surfaces of the leaves. Mortality percentage of mites was calculated using Abbot and Henderson Tillton formulas. After normalizing the data, mean comparison was carried out using Duncan Multiple Range Test. Results indicate significant differences among the main plot factors, and treatment in the 1st and 2nd levels (3 and 5 mites on abaxial surface of each leaf, respectively) was more effective than the 3rd level 7 mites on abaxial surface of each leaf). Mean comparison of the mite mortality among different acaricides showed that bromopropylate with 97.8 and 95.8% mortality at day 14 (in the 1st and 2nd sampling time, respectively) was more effective than fenazaquin and fenpyroximate. It could be concluded that taking population density of the pest into consideration for choosing the right spraying time can increase the effectiveness of the acaricides.

Downy mildew caused by Pseudoperonosprora cubensis is one of the most important foliar diseases of greenhouse cultivated cucumber which causes significant economic damages in Iran annually. For theassessment of the effect of potassium phosphate (Fosphite ® WSL 53%) on the control of the disease, two areas (Yazd and Varamin) with precedent infection were selected and experiment was performed in a completely randomized block design with 5 treatments and four replications during 2012. Treatments included Fosphite at the rates of 3, 4 and 5 ml/l, famoxadone cymoxanil (Equation ® pro 52.5% WDG) at the rate of 0.3 g/l and control without spraying. Spraying was carried out twice immediately after the appearance of the disease symptoms within 7-10 days. The disease severity was assessed by measurement of disease caused spots on the surface of leaves and sporangium formation 7 days after the second spraying. Data collected were analyzed by SAS software and Duncan's multiple range tests for mean comparison. Results indicate that fungicide application caused significant decrease in the disease severity compared with the control treatment. There is a significant difference between Fosphite 5 ml/l and Equation pro treatment but no significant differences are observed among 3, 4 and 5 ml/l treatments (P£0.05). Minimum disease severity occurred in Fosphite 3, 4 and 5 ml/l followed by Equation pro 0.3 g/l application in the control of downy mildew.

Serpentine leafminer, Liriomyza trifolii (Burgess) is one of the most important pests of vegetables, especially on cucurbit in greenhouses. A study was conducted to determine the efficacy of some insecticides including acetamiprid (Mospilan® SP 20%) at the rate of 750 g/ha, abamectin (Vertimec® EC 1.8%) at the rate of 600 ml/ha and cyromazin (Trigard® WP75%) at the rates of 100 and 200 g/ha in the first year of the studies and at the rates of 200, 300 and 400 g/ha in the second year of the studies on L. trifolii. All the experiments were conducted in a completely randomized block design with 4 replicates. In the first year 3 days after applying the insecticides abamectin and cyromazin (200 g/ha) showed 78.37% and 75.21% mortality, respectively while acetamiprid showed 11.30% mortality which is the lowest effect against the pest larvae. In the second year of the experiments after two times of sampling (8 and 12 days after spraying), abamectin showed 100% and 94.32% mortality and cyromazin (200 g/ha) with 99.64%and 98.14% mortality, cyromazin (300g/ha) with 97.27% and 99.22% and cyromazin (400g/ha) with 98.90% and 100% mortality were the most effective insecticides, while acetamiprid with 20.96% and 37.81% mortality, did not show considerable efficacy.

Shot hole disease caused by Wilsonomyces carpophilus is one of the most important diseases of apricot in the world and copper-based fungicides are usually used as the chemical control of this disease. New copper-based fungicide (Misho Bordeaux® SC 18%) contains Bordeaux mixture active ingredient. In the present study, its efficacy was compared with common fungicides including Bordeaux Fix SC 18%, copper oxychloride (Mishocap® WP 35%) and captan (Captan® WP 50%) for the control of shot hole disease on apricot. The experiment was carried out in Alborz (Savojbolagh), Semnan (Shahrood) and Kohgiloyeh and Boyerahmad (Yasuj) provinces in a randomized complete block Design (RCBD) with 8 treatments and 4 replications. Treatments included 5, 10 and 15 ml/L of Misho Bordeaux, Bordeaux Fix 15 ml/L, Mishocap 3 g/L, Captan 3 g/ L and controls (without any spraying and with water spraying). Fungicides were applied at two stages (the first spraying time was after fall of the leaves and the second one was at bud inflation). Disease incidence percentage and disease severity percentage were measured and analyzed in the three provinces. Mean comparison of disease severity and disease incidence percentages were done by Duncan's multiple range test ( =1%). The results show that there are significant differencesbetween all the fungicide treatments and the controls. Misho Bordeaux 15 and 10 ml/L had better control effects than the other treatments. Disease severity percentages in Alborz province were 4.27 and 4.35, in Semnan province were 7.00 and 9.25 and in Kohgiloyeh and Boyerahmad province were 3.67 and 4.70 respectively. Disease incidence percentages in trees sprayed by Misho Bordeaux 15 and 10 ml/L in Alborz province were 15.00 and 15.75, in Semnan province were 8.25 and 10.25 and in Kohgiloyeh and Boyerahmad province were 13.00 and 17.00 respectively.

The experiment was conducted in 2006 and 2007 to evaluate the efficacy of some herbicides against weeds in tuberose fields in Dezful, Iran. The experimental design was a completely randomized block with 14 treatments and three replications. Treatments included application of paraquat POST at 0.6 kg ai/ha, oxyfluorfen PRE at 0.48 kg ai/ha, ioxynil POST at 0.66 kg ai/ha, trifluralin PPI at 1 kg ai/ha 10 days before planting, trifluralin PPI at 1 kg ai/ha, EPTC PPI at 4 kg ai/ha, oxadiazon PRE at 0.36 kg ai/ha, alachlor PRE at 2.5 kg ai/ha, diuron PRE at 1.6 kg ai/ha, atrazine PRE at 1.2 kg ai/ha, atrazine PRE at 0.8 kg ai/ha one handweeding, 2,4-D haloxyfop-r–methyl POST one week after 2,4–D applicationat 1.44 0.08) kg ai/ha, weedy and weed free checks. In both the years of the experiments, compared to the weedy check, application of diuron and atrazine, with 100% and 97%, were the most effective treatments in reducing the total number of weeds, respectively. 2, 4 - D haloxyfop - r – methyl with 95% was the most effective treatment in reducing total dry weight of weeds. Compared with the weedy check, after weed free check application of atrazine one handweedingwith 5.87 ton/ha-1 was the most effective treatmentinincreasing spike yield. In2006 and 2007, application of ioxynil and atrazine one handweeding had the highest level of corm weight respectively. Considering the results of this experiment, application of each of atrazine PRE at 0.8 kg ai/ha one handweeding, oxyfluorfen PRE at 0.48 kg ai/ha, ioxynil POST at 0.66 kg ai/ha, atrazine PRE at 1.2 kg ai/ha or handweedings throughout the growing season of tuberose are recommended.

Onion thrips, Thrips tabaci is a key pest of onion in Iran. Several spraying per season are applied against it. Therefore, replacing regular pesticides with more efficient and low-risk ones is necessary. In this study, the efficacy of insecticides against onion thrips was studied in two provinces (Esfahan and Markazi). The study was conducted in a completely randomized block design with six treatments including Cypermethrin® EC 40% (0.5L per 1000L), Dichlorvos® EC 50% (2L per 1000L), Malathion® EC 57% (1. L per 1000L), a new insecticide, spirotetramat “Movento® SC 100” (0.72L per 1000L and 0.60L per100 L) and control, in four replications. Sampling was done one day before treatment, 3, 7 and 14 days after treatment. Number of thrips per 10 plants per plot was recorded and efficacy of the treatments was calculated using Henderson- Tilton formula. Data were subjected to analysis of variance, followed by Duncan test. Damage indices were compared using Kruskal-Wallis non-parametric test. Efficacy of the treatments were different in Esfahan; Movento (0.72 L/1000L) had the highest efficacy in three sampling dates after spraying 95%, 95% and 83% respectively); it was followed by Movento (0.60 L/1000 L) (88%, 88% and 79%). The efficacy of Dichlorvos, three days after the treatment (88%), was close to the efficacy of Movento. Damage index for Movento, seven days after the treatment, was the lowest. In Markazi, the efficacy of Movento was the highest, while no significant differences were detected among the treatments. In summary, the new insecticide spirotetramat (Movento® SC 10%), at a rate of 0.60 L /1000 L, had an acceptable control rate against onion thrips.

Various factors may lead to pesticide efficiency increment, and adjuvant may be considered as the most important one. Spider mite, Tetranychus urticae, is a key pest in greenhouse especially on cucumber. Its damage and control measures involve high expenses annually. This research was conducted to study the effect of Dioctyl Sodium Sulfosuccinate as an adjuvant, dispersing and wetting agent, to evaluate the effects of hexythiazox (Nisoron® EC 10%) on T. urticae in greenhouses of Chah Akrami and Ashkezar, in Yazd province during the years 2013 and 2014. This experiment was performed based on randomized complete block design under greenhouse condition with 5 treatments including hexythiazox with recommended dosage (100ml/100L) as control, hexythiazox (5% dosage reduction)ǘꧭ, hexythiazox 10% dosage reduction) Adjuvant, hexythiazox (15% dosage reduction) Adjuvant and hexythiazox 20% dosage reduction) Adjuvant. Dioctyl Sodium Sulfosuccinate (Adjuvant) was used with recommended dosage (75 ml/100 L). Sampling was done after 1, 2, 3, 7, 10, 15 and 21 days after spraying. hexythiazox treatment as control showed significantly more efficiency at the initial sampling intervals (95.93±0.8; 97±0.57 in Chah Akrami and Ashkezar respectively), but dropped over time. According to the present results Dioctyl Sodium Sulfosuccinate application showed significant effects on efficiency increment (25% compared to recommended dosage of hexythiazox after 15 days), dosage reduction (15%) and duration of hexythiazox efficiency.