Journal of Applied Research in Plant Protection
Year:2021 | Volume:10 | Issue:2|Papers Count:9

This study aimed to model spatial distribution of alfalfa plant bug Adelphocoris lineolatus in six alfalfa fields during two growing seasons. Weekly sampling was started early in the spring and continued until cutting the hay. The plant bugs were sampled using six to eight 180°,sweeps per 400 m2 grid and bugs captured by sweep net were counted. The data were analyzed using regression methods, dispersion indices and geostatistical analysis. According to the results, the variance to means ratio, dispersion indices (ID), David-Moore index (IDM), Lloyd’, s index (x*) and Green's Index (Cx) were greater than one, indicating the aggregated distribution. Regression statistics also showed that in all studied fields in the first and second year, distribution of the pest was aggregated and random, respectively. Due to the high coefficients of determination and the low standard error values of the regression coefficients, Taylor’, s model was more efficient than Iowa’, s model. The results of geostatistics confirmed the results of regression methods and distribution coefficients,and K index was less than 0. 8 for 18 out of 20 datasets, which indicates the aggregated distribution. These results can be used in sampling and pest management programs of alfalfa plant bug.

Cold storage is a common technique to prolong the shelf life of the mass-reared natural enemies in insectaries. In this research, one-day and two-day old eggs of the common green lacewing, Chrysoperla carnea were stored in refrigerator (5±, 1°, C, and full darkness) for 3, 5, 7, 10, 14, 21 and 30 days and egg hatching rate, survival and developmental times of larva and pupa as well as longevity and fecundity of adult females were subsequently assessed. Hatching percentage of both one-day and two-day old eggs did not negatively reduce for up to 7 days of cold storage (37. 5 and 39. 2 hatching percentages, respectively), but a significant reduction was observed in longer storage durations and reached to 0 percent after 30 days. The effect of “, age”,factor on egg hatching rate was largely dependent on cold storage duration. Therefore, there was no significant difference between hatching rates of one-day old eggs compared with that of two-day old eggs up to 14 days of cold storage, while hatching percentage of two-day old eggs was significantly lower compared with that of one-day old eggs at 21 days cold storage duration. Cold storage of one-day and two-day old eggs had no adverse effect on the larval survival rates up to 14 and 10 days, respectively. But larval developmental time increased significantly even after a short 3-days duration of cold storage. Moreover, cold storage of one-day old eggs for 7 days and two-day old eggs for 3 days significantly reduced female fecundity (37. 5 and 66. 1 percent, respectively). In conclusion, one-day old eggs can be cold stored for up to 5 days, and cold storing of two-day old eggs is not recommended because of its high subsequent adverse effects on female longevity and fecundity.

In order to evaluate the effect of different methods in control of weed damages on pumpkin, an experiment was conducted based on randomized completely block design with four replications in 2019. Treatments consisted of weed free, complete weeding, mulch (clear and dark plastic), intercropping with quinoa, once weeding and three herbicides: Trifluralin (7. 5 liters of commercial material per hectare) before planting and after crop growth, indaziflam (100 ml commercial material per hectare), pendimethalin (6 liters commercial material per hectare). Indaziflam and pendimethalin chemical treatments were applied after emergence on July. Results showed that the dark plastic mulch caused the maximum dry matter (141. 4 g/m2) and fresh (289. 8 g/m2) weight of pumpkin leaf and the maximum dry matter (78. 5 g/m2) and fresh (641. 6 g/m2) weight of pumpkin shoot in comparison of other treatments. In addition, dry matter of weeds got decrease up to 90 percent just through by type of dark plastic from mulch treatment and 97 percent by clear one. Furthermore, it caused 49 and 129 percent increasing respectively in fresh and dry matter weight of pumpkin. On condition of chemical control, using Trifluralin herbicide before of planting caused the fruit diameter (13. 4 cm), fruit area (46 cm) and seed (35. 5 g) dry matter of pumpkin so improved the yield in comparison other chemical treatments. Finally, using different mulching treatment got yield increased up to maximum, proper control of weeds and decreased the environmental pollution through decreasing of chemical materials.

Cucumber powdery mildew disease which is caused by Golovinomyces cichoracearum, is one of the most important diseases of cucumber in Iran and world. In this study, the efficacy of two new fungicides, Safir®,SC 32. 5% and Diforobin SC 32. 5%, in the control of cucumber powdery mildew disease were evaluated. Experiments were carried out in Alborz and Tehran provinces in a Randomized Complete Block Design (RCBD) with 9 treatments and 4 replications under greenhouse conditions. Treatments included 0. 5, 0. 6 and 0. 75 ml/L of Safir®, ,0. 5, 0. 75 and 1 ml/L of Diforobin,0. 4 ml/L of tetraconazol (Domark®,EC 10%) and 5 g/L of bicarbonate potassium (Kaliban®,SL 85%) along with control without any spraying. Foliar applications of fungicides started once after early symptoms appearance and followed up at 5-10 days intervals. Evaluation of the treated plots were done before each spraying and 12 days after last spraying as the disease severity index (DSI). Disease severity was classified using the Horsfall and Barrat scale. Mid-point of disease severity calculated for each plant. The efficacy comparisons revealed that Safir®,0. 75 ml/L, Diforobin®,0. 75 and 1 ml/L and Domark®,0. 4 ml/L as a standard treatment had the same effects due to statistical points and decreased the Area Under the Disease Curve by the 90% compared to unsprayed check treatment. Based on the results, the fungicides Safir®,and Diforobin®,at 0. 75 ml/L are suitable for 7 to 14-days intervals.

Persian lilac (Melia azedarach,Family: Meliaceae) and fig (Ficus carica,Family Moraceae) are important medicinal plants native to Iran. In this study, the antiviral effect of the crude ethanolic and aquatic extracts of the persian lilac and fig plants in decreasing disease severity caused by Cucumber mosaic virus (CMV) in cucumber plants was assessed using with the double antibody sandwich ELISA (DASELISA) and semi quantitative-RT-PCR (Sq-RT-PCR). In addition, the transcription level of PR-1 gene and specific activity of phenylalanine ammonia-lyase (PAL) enzyme were evaluated using Sq-RT-PCR assay. ELISA results showed that the presence level of CMV in cucumber seedlings was significantly decreased up to 15 days after their treating with the 100 ppm of ethanolic and 1000 ppm of aquatic extracts of fig and persian lilac plants in compare to the non-treated control plants. The PR-1 expression level and PAL enzyme specific activity were also significantly increased compared to the non-treated control infected plants in samples treated with the ethanolic extracts of persian lilac and fig plants at the concentration of 100 ppm up to 15 days after treatments. Disease severity was also significantly decreased in cucumber seedlings treated with the 100 ppm concentration of ethanolic extract of the persian lilac and fig plants. Totally, results of this study indicated that the systemic acquired resistance might be activated against CMV by applying ethanolic extracts of persian lilac and fig plant used in this study in treated cucumber seedlings through different molecular and biochemical mechanisms.

Botanical pesticides are considered as suitable alternatives to the chemical insecticides in the integrated pest management program due to environmental compatibility, low toxicity to non-target organisms and low environmental stability. In this study, the effects of field concentrations of four botanicals and one biological control agent in the control of cabbage aphid were investigated during two years. The treatments including botanical product Palizin,(in two treatments without and with Citra-Plus,oil), commercial Neem product (Neem-Azal, ), Dayabon,botanical product and a biological product based on Beauveria bassiana, in comparison with the control were used in the stem growth stage of the oilseed rape. The experiment was performed in a randomized complete block design with 6 treatments and 4 replications. The effectiveness of the treatments was evaluated by sampling and comparing the aphid population during 4 times: one day before treatment, 3, 7 and 10 days after treatment. Henderson-Tilton formula was used to calculate the percentage of modified losses. The results of study showed that the treatments of Palizin, , Palizin,+ Citra-Plus,oil and Dayabon,are effective compounds in the control of cabbage aphid and can be considered as a suitable alternative to chemical insecticides in the integrated management program of this pest. Neem-Azal,and Naturalis-L,products are not effective in controlling cabbage aphid.

Tetranychus urticae is one of the most important cucumber pests in the Iranian greenhouses. The efficacy of cyflumetofen (Danisaraba®,SC 20%) with two concentrations of 0. 75 and 1. 0 ml/lit was evaluated and compared with two conventional pesticides, tetradifone (Tedion®,EC 7. 5%) and spiromesifen (Obron®,SC 24%) in cucumber greenhouses of Jiroft and Varamin cities and the cyflumetofen residual amount with two doses was measured. Sampling was done at 1 day before spraying and 3, 7 and 14 days after spraying, and the number of alive mites was counted. In both cities, there was significant difference among treatments for 3 and 7 days after spraying and the effectiveness was higher at 7th day, then it reduced on the following days. In Jiroft, at 7th day after spraying, cyflumetofen 1. 0 ml/l had the highest effect with 96% efficiency, followed by spiromesifen, cyflumetofen 0. 75 ml/l, and tetradifone with 95, 84, and 73%, respectively. In Varamin, the efficacy of cyflumetofen 1. 0 and 0. 75 ml/l, spiromesifen and tetradifone at 7th day after spraying was 91. 5, 72, 70% and 67. 25%, respectively. To investigate the residual amount of cyflumetofen, 20 samples of cucumber fruit were extracted and analyzed in the laboratory. The results showed that spraying cyflumetofen in two used concentrations did not leave any residues on the cucumbers fruits at 3 and 7 days after treatment. Overall, the results showed that the cyflumetofen 1. 0 ml/lit compared with tetradifone and spiromecifen can be used as suitable acaricide to control spider mite in cucumber greenhouse.

Onion thrips, Thrips tabaci is the most well-known and most common polyphagous thrips worldwide and is one of the major pests of legume fields, causing significant damage to various crops each year. In this study the life table parameters of onion thrips was studied on lentil and chickpea plants at laboratory conditions (25 ±,1°, C, 70 ±,5% RH and 16: 8 h L: D). The total life cycle from egg to adult and the mean adult longevity on lentil and chickpea plants were calculated as 13. 81 and 15. 81 days, and 13. 44 and 13. 91 days respectively. The females laid 43. 90 and 24. 84 eggs on average. The immature mortality was 10. 01 and 18. 58 on lentil and chickpea, respectively. The net reproductive rate (R0) was 39. 51 and 20. 22, and the intrinsic rate of increase (rm) was 0. 185 and 0. 133 respectively. The finite rate of increase (λ, ) was 1. 20 and 1. 14. However, mean generation time (T) and doubling time (DT) on two host plants was calculated as 19. 81, 22. 47 and 3. 73, 5. 18 day. The results showed that all of the life table parameters of T. tabaci on lentil plant were statistically significantly different from chickpea plant. According to these results, it seems that lentil is a more suitable host plant for onion thrips.

Stem or black rust caused by Puccinia graminis f. sp. tritici (Pgt) is one of the most important fungal diseases of wheat in the world. So far, several physiological races of Pgt (more than 200 races with different pattern of pathogenicity) have been identified worldwide. One of the most virulent recognized stem rust races is the race TTKSK (Ug99) that was first observed in Uganda in 1998. Gene Sr31 had created resistance to stem rust on wheat in more than 40 years to the point where it was imagined eradicating this disease (Pretorius et al. 2000). The Ug99 race was reported from Kenya in 2002, Ethiopia in 2003, and Yemen in 2006. There has been evidence for the arrival of this race in Iran since 2001, but official report of this race was delayed until 2007, probably due to unfavorable environmental conditions for establishment and spread of the disease (Nazari et al. 2009). The hypothetical route of movement and migration of this race is from the African continent to Central Asia and the Indian subcontinent through Iran. In Iran, the race TTKSK (Ug99) was reported for the first time from Borujerd and Hamedan in 2007, then observed in Ahwaz and Azadgan plain of Khuzestan in 2009, again observed from Borujerd in 2011 and Kelardasht of Mazandaran province in 2013 (Patpour 2013). In the year 2016 infected leaf and stem samples of the wheat stem rust disease were collected from different areas of country and after transferring to the greenhouse of the rusts of Seed and Plant Improvement Institute, Karaj, three isolates were single-pustuled and proliferated. Following single-pustulating of isolates, employing the Jin et al. (2008) method, stem rust races were determined using a set of 20 North American differential genotypes. The infection type of differential genotypes was recorded 14 days after the inoculation,based on a modified scale of 0-4 McIntosh et al. (1995). According to the results, isolate of Pgt that was collected from the Hashtrood area of the East Azarbaijan province was identified as TTKSK (Ug99). In addition, along with international differential genotypes, the commercial cultivars of Shiroudi, Falat and MV17, having the Sr31 gene in their background, were used (Patpour 2013). Regarding the emergence of high-infection type on differential genotypes and commercial cultivars, the isolate from the Hashtrood region was confirmed as race TTKSK (Ug99) (Fig. 1). Since stem rust has not been a serious disease on wheat in the cold climate of the country, according to studies, resistant cultivars to wheat stem rust in cold climates are limited (Patpour 2013). Proper management strategies for the control of Ug99 race and its variants are urgently required to avoid possible epidemics and economic crop losses under favorable environmental conditions, and consequent spread of this disease in the country, which could lead to reduced food security in Iran and the countries on the migration route of the race. According to the Food and Agriculture Organization (FAO), if the Ug99 race and its variants remain controlled, global production of wheat will be directly reduced by up to 37% (FAO 2014).