Journal of Applied Research in Plant Protection
Year:2017 | Volume:6 | Issue:2 |Papers Count:10

The pistachio fruit hull borer moth, Arimania komaroffi Ragonot (Lepidoptera: Pyralidae) has become a major pest of pistachio in recent years. The purpose of this study was to determine the lower threshold temperature and thermal constant of this pest under laboratory condition which can be used in predicting the time of pest control. Immature stages of this pest were reared at four constant temperatures 25, 27. 5, 30, 32. 5 and 35° C (± 1), 65± 5% RH, and 16: 8 L: D photoperiod on fruit of Ohadi pistachio cultivar in growth chamber. Lower threshold temperature (T0) and thermal constant (K) of various stages of this pest were calculated with ordinary linear regression method and Ikemoto & Takai method. Moreover, thermal requirements for different generations of pest were determined under the field conditions during two years, 2013-2014. According to the results the lower threshold temperature for total immature stage (from egg to adult emergence) of this pest with ordinary linear regression and Ikemoto & Takai were 10. 29 and 10. 42° C, respectively. Thermal constant for completing immature period (egg to adult emergence) was calculated as 826. 05 and 820. 11 degree-days with ordinary linear regression and Ikemoto & Takai equations, respectively. Thermal requirements were measured as 763. 7, 750. 9 and 811. 7 DD for first, second and third generations under field conditions which is consistent with laboratory results. Results of this study could be used in forecasting and pest management of this pest.

Brown rot disease of citrus fruits caused by Phytophthora citrophthora and Phytophthora parasitica is one of the most threats to citrus plantation in northern Iran. In evaluation of different methods to control of citrus brown rot, an experiment was achieved in Northern Iran based on Randomized Complete Block Design (RCBD) in factorial test with five replications. In reciprocal effects study of fungicides (metalaxyl, cupper oxychloride and burdux mixture) and skirt pruning, a significant difference was observed among the treatments. The results showed that the best treatment was obtained from the application of cupper oxychloride + skirt pruning in August. In reciprocal effects study pruning and fungicides application time, no significant differences were observed among treatments, however maximum and minimum percent of decay were depended on "no pruning + spraying in September and pruning + spraying in May" respectively. There were also differences among spraying time and fungicides application, as maximum and minimum percent of decay were related to application of metalaxyl and cupper oxychloride in September.

To assess resistance of different genotypes of safflower to safflower shootfly, 10 genotypes of this plant were evaluated in autumn sowing. The experiments were conducted in a complete blocks design with three replications in Agricultural Research Station Gryzeh-Sanandadj and two growing seasons (2011-2012 and 2012-2013). In this trial some parameters such as rates of infestation and damage, yield, weight of 1000 seeds and percent of oil were measured and compared in different plots. Analysis of variance of percent of infested capitula, number of larvae and pupae, number of damaged seeds, weight of 1000 seeds, percent of oil of seeds, and yield revealed significant difference between genotypes at the 1% probability level. Based on the comparison of mean values, the local varieties named Isfahan and Lesaf had highest and Syrian had lowest percent of infested capitula. Accordingly, local variety of Isfahan had maximum and local genotype of Marand had minimum number of larvae and pupae per capitula. The Lesaf genotype was more susceptible and had highest percent of damaged seed and genotypes of local Isfahan, Marand and Syrian had the lowest number of damaged seeds. Evaluated genotypes were divided into two main groups based on the results. The first group including Syrian, local Marand, Sina, 411 and IL111, with lowest percentage of infested capitula, lowest number of larvae and pupae in the capitula and lowest percent and number of damaged seeds, could be considered as relatively tolerant to the safflower fly. Syrian and local genotype of Marand, were more tolerant among the rest. The second group including Isfahan, Lesaf, S-541, Dinser and coarse-grained Almaneh, with the highest percentage of infested capitula, the highest number of larvae and pupae in the capitula and highest percent of damaged seeds, could be considered as susceptible to the safflower fly. Local cultivar of Isfahan and Lesaf were more sensitive than others.

Aspergillus parasiticus and Aspergillus flavus are the most important agents for contamination of food and are capable of production of carcinogenic toxins. Increasing awareness of optimal growth conditions helps to control and prevent the contamination and toxicity of these fungi. This experiment was conducted in order to study the effect of temperature, pH and seed moisture content on the growth of these fungi. The effect of corn seed moisture, at levels 15, 18, 21, 24, 27 and 30 percent on corn, and temperature, at level 18, 22, 25, 28, 31 and 34 ° C, in PDA medium and the effect of pH at level 3, 4, 5, 6 and 7 in PDB medium were investigated on the growth of these two fungi. The growth rate of fungi and dry weight of mycelium fungi in different treatments was evaluated in a completely randomized design in four repetitions. Statistical analysis was performed by using SAS 9. 1 software. Also, to determine the presence of toxins in fungi was used of coconut– agar medium. The results showed that the optimum growth conditions are for A. parasiticus at 31° C, pH= 5 and seed moisture content of 27% and for A. flavus at 28° C, pH=6 and seed moisture content of 27%. It was also found, both fungal have the ability to produce aflatoxin. According to the results of this research can be concluded that A. parasiticus and A. flavus have the better grow in tropical and subtropical regions and decrease moisture content, low temperatures and cool in stock can play an effective role in preventing the growth of these fungi and in reducing their toxin production consequently.

Viral diseases are among the most important diseases of wheat in Chahar Mahal Va Bakhtiari province. During 2005-2008 growing seasons, the efficacy of seed treatment with imidacloprid and thiamethoxam on three cultivars of wheat were tested for the control of viral diseases, including: Barley yellow dwarf virus (BYDV-PAV and BYDV-MAV serotypes), Cereal yellow dwarf virus (CYDV-RPV serotype), Wheat dwarf virus (WDV), Iranian maize mosaic virus (MIMV), Barley yellow striate mosaic virus (BYSMV) and Wheat streak mosaic virus (WSMV), with natural vectors under field condition in Shahrekord. The experimental design was a split plots arrangement of a randomized complete block with four replications. Disease incidence was determined based on the percentage of plants exhibiting symptoms and ELISA test. At harvest, data was collected on yield and yield components. Results showed that seed treatment insecticides increased grain yield and yield components, with significant reduction occur BYDV-PAV, BYDV-MAV, CYDV-RPV, WDV, IMMV and BYSMV in wheat plants compare with untreated control, while occur WSMV was not affected. “ Shahriar” wheat cultivar treated with imidacloprid was the most effective treatment for control of viral diseases. The effect of seed treatment with imidacloprid was higher than thiamethoxam. Occurrence virus diseases on Alvand cultivar was more than other cultivars. The amounts of infection to WSMV, BYDV-PAV, CYDV-RPV, WDV, BYSMV, BYDV-MAV and MIMV in seed treatment plots were from highest to lowest (in descending order).

One of the serious plant diseases in Iran is Citrus Greening disease. That have been reported from different region of country. Research on the vector Diaphorina citri, is essential due to presence in our country. Because of high reproduction rate and rapid development, this insect has a propensity to develop resistance to many classes of insecticides. One way to delay pest resistance is application of insecticides from different classes, so studying new insecticides is essential and inevitable. This experiment was done based on a completely randomized block design with 6 treatments (clothianidin (300 ppm), acetamiprid (500 ppm), Dimillin® (750 ppm), chlofluazuron (400 ppm), pyriproxifen (750 ppm), and control (spray with water)) and three replications A two-year study (2011 – 2012) was conducted in a citrus garden in Kerman Province. Sampling of trees was performed one day before spraying, and on the 3rd and 10th day after treatment. The highest and lowest mortality percentage (89. 88, 27. 34) were observed on clothianidin and pyriproxifen, respectively, Ten days after spraying, Ten days after spraying, efficacy on nymphs were 83. 18, 7. 94, 84. 80, 74. 32 and 63. 33 percent for clothianidin, stamiprid, diflubenzuron, chlofluazoru and pyriproxyfen, respectively. Diflubenzuron and pyriproxyfen had lower efficacy on adults compared to nymphs. In general, all insecticides, except pyriproxyfen, can be recommended for citrus psylla control.

Nesidiocoris tenuis Reuter (Hemiptera: Miridae) is a zoophytophagous mirid known as a potential biological control agent of whiteflies and Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae). This predator is widely used in integrated pest management programs in greenhouses. In this study, side effects of four pesticides including pymetrozin, abamectin + chlorantraniliprole, mancozeb and iprodion + carbendazim were evaluated on survival and number of offspring N. tenuis Adults of predators were exposed to the pesticides through residual and oral routes simultaneously. None of the pesticides except abamectin + chlorantraniliprole caused significant mortality on predator but all of them affected the number of offspring. The highest reduction in fertility performed by abamectin + chlorantraniliprole (92. 5%). Followed by Iprodion + carbendazim (43. 22%), pymetrozin (37. 44%) and mancozeb (17. 14%) respectively. Toxicity of pesticides was calculated based on the reduction coefficient, Ex. According to IOBC Standard abamectin + chlorantraniliprole was classified as moderately harmful, pymetrozin and iprodion + carbendazim as slightly harmful and mancozeb as harmless.

Tomato leaf miner, Tuta absoluta (Meyrick) is a serious key pest of solanaceaous crops specially tomato. The insect is an oligophagous pest which is native to South America especially to Peru. Because of the importance of the pest and irreparable damage on solanaceous plants, population parameters of the insect on three host plants including tomato, eggplant and pepper were determined by life table method. All trials were performed in a growth chamber at 25± 1° C, 60 ± 5% RH and 16: 8 h (L: D) photoperiod. The tomato leaf miner was reared on each host plant for two generations and eggs of the 3rd generation were used in the experiments. The value of parameters, rm (intrinsic rate of population increase), λ (finite rate of population increase), Ro (net reproductive rate) and T (average one generation) for tomato leaf miner on tomato and eggplant were (0. 094± 0. 006, 0. 0615± 0. 005 day-1), (1. 098± 0. 007, 1. 063± 0. 006 day-1), (22. 48± 4. 72, 10. 95± 2. 26 offspring) and (33. 35± 0. 32, 38. 90± 0. 27 day) respectively. Also, Tomato leaf miner did not completed life cycle on pepper. The results show significant differences between the different host plants. These results can be used for a successful IPM program against the tomato leaf miner in solanaceous fields and greenhouses.

Date sap beetle, Carpophilus hemipterus (Col.: Nitidulidae) is one of the post-harvest pests of date palm fruits which causes a lot of damages under store conditions. There are several methods for controlling stored product pests and one of the major methods is applying entomopathogenic fungi as biological control agents. In this study, the fungus B. bassiana Iran 1395C and M. asisopliae isolate Iran 1018C were used to control fourth instar larvae and adults. Bioassay method for larvae was performed with filter paper impregnated with spore suspensions in sterile Petri dishes and for adults by immersing insects in spore suspension. Spore suspension at concentrations of 3×108, 3×107, 3×106, 3×105 conidia/ml was prepared in Tween 0. 02%, then mortality rate of adults was examined after 3, 7, 9, 11, 13 days and for larvae after 3, 7 and 9 days. The results showed that mortality rate increased by increasing time and concentration of spore suspension. Mortality rates of adults for abovementioned concentrations using B. bassiana were 24. 4, 14. 4, 12. 8 and 10. 5% and for larvae were 83. 3, 76. 7, 72. 2 and 71. 1%, respectively. Moreover, it is revealed that fungal application at a concentration of 3×108 conidia/ml after 15 days and at all concentrations after 9 days lead to the highest mortality rate of adults (30%) and larvae (100%), respectively. Regarding M. anisopliae, mortality rates of larvae for were 78. 9, 75. 6, 73. 3 and 54. 4% and for adults were 51. 7, 20. 6, 12. 2 and 10%, respectively. On the other hand results showed that the fungus at a concentration of 3×108 after 15 days and at a concentration of 3×105 after seven days caused the highest mortality rate of adults (63. 3%) and larvae (97%), respectively. Results indicate that fungal isolates used in this study have high insecticidal activity against larvae and adults of date sap beetle, and can be used for product protection after harvest.

In order to evaluate the antioxidant activity in the pear cultivars including Dargazi and William Duchesse after inoculation with E. amylovora, an experiment carried out in factorial randomized complete block design with three replications. The resistance level has been determined with calculation of the length of lesion to the overall sheet length percentage. In order to find out the plant resistance mechanisms to the pathogen, ascorbate peroxidase (APX), catalase (CAT), guaiacol peroxidase (POX), H2O2 accumulation and total antioxidant capacity (TAC) were measured at zero, 3, 6, 9, 12 and 15 days after the inoculation by E. amylovora. According to the data obtained all biochemical parameters are affected by pathogen attack. In addition, most of the biochemical parameters showed a significant increase on the leaves of Dargazi cultivar compared with William Duchesse cultivar after pathogen infection. Catalase and peroxidase enzymes activity in the Dargazi cultivar were significantly different (P≤ 0. 01) with William Duchesse cultivar during inoculation, and the highest activity were obtained at the sixth to 12 days after the treatment. Investigation of disease progression in shoot showed that the progression rate of necrosis in pear shoots was related with index of varietal susceptibility, so that William Duchesse with high index of varietal susceptibility, had higher rate of necrosis.