نشریه گیاه پزشکی کاربردی
سال دهم شماره 1 (پیاپی 29، شهریور 1400)

The effect of acaricide Abamectin (Agrimec Gold® SC, 8.4%) was investigated to control the two-spotted spider mite Tetranychus urticae on cucumber in greenhouses in Yazd and Jiroft. Abamectin (Agrimec Gold®) at two doses of 0.185 and 0.200 ml/lit was compared by Tetradifon (Tedion® EC, 2 ml/lit) and Sperimesifen (Oberon® SC, 0.5 ml/lit). Sampling and counting of live mites on the lower surface of the leaves were done at one day before and 3, 7 and 14 days after spraying respectively. Statistical analysis was conducted using SAS software with randomized complete block design. Results in both cities showed Abamectin had high mortality of mites at 3, 7 and 14 days after spraying and the effect of Sperimesifen was higher than Tetradifon. In Yazd province Abamectin treatment at doses of 0.185 and 0.200 ml/lit showed 100 percent mortality on mites at 3, 7 and 14 days after spraying and in Jiroft, efficacy of two doses were 92.79-99.48 % of mortality. In Yazd, efficacy of the sperimesifen was 66.1-99.5 percent but in Jiroft on day 3 Sperimesifen had caused 100 % of mite mortality and then decreased to 98.78% on day 14 after spraying. Investigation of preharvest interval of Abamectin at doses of 0.185 and 0.200 ml/lit in cucumber samples showed that 7 days after spraying is acceptable according to the Syngenta company claim, so based on efficiency test, it is recommended to use a dose of 0.185/lit of this acaricide to control TSSM in greenhouse cucumbers.

Cutworms (Agrotis spp.), are insects from order Lepidoptera and family Noctuidae which damage crops by feeding or cutting the stems of seedlings at or below the growing point. In this study, the Agrotis species in sugar beet fields were identified in Naghadeh city of West Azerbaijan province during 2020 using pheromone and light traps. Then the number of its generations in the field was determined. Three fields with 2 hectar space for each were selected in Southeastern and Northwestern of Naghadeh. Samples were collected weekly from pheromone and light traps and sent to the Research Center of Plant Protection of Iran for identification. Five Agrotis species were identified totally. Agrotis segetum, A. ipsilon (Hufnagel), A. spinifera Hubner., A. exclamationis L. and A. sp. near herzogi Rebel. A. segetum was the dominant species in all of the studied fields. Data showed that this pest had 3 generations during one crop season in the studied area. The first generation was showed up from the end of April and reached its peak in the second half of May. The next two generations of this pest were completed in late June and late July, respectively. The mean density of pest were as 16.8 eggs, 14.7 larvae and 11 pupae on 10 infected plants showed the highest peak during the second generation.

Molluscs are among the most important group of agricultural plant pests. Physa acuta, as an invasive species in horticulture, vegetables and specially rice farms takes a serious attention. In this study, through sampling from four pints in Jajroud River including Fasham, Saeed Abad, Khojir and Pakdasht, the species was reported from all the sampling points. There were no samples collected in summer season and samples collected in spring and autumn showed no significant difference in morphological features. The presence of the species would be considered as an alarm for further invasion to farms and gardens along the riverside.

Lobesia botrana (Lep., Tortricidae) is one of the most important pests of vineyards in Iran and the world. Sex pheromone plays an important role in tracking and controlling this pest and is inevitable to get the best time for spraying and prevent indiscriminate spraying. In this study, changes in the population density of grape-eating larvae and the peak time of insect flight in different generations of the species were investigated by installing pheromone traps in the garden of Kashmar Research Center in Khorasan Razavi province through 2020. In this study, four peak points of adult insect flight were recorded. The first flight peak was reached on April 15, and then reached the peak of the second flight with a decrease on June 3, and after this peak on July 7, the peak of the third flight occurred, and finally on September 5, the fourth peak of the flight was observed. After the last peak, due to the gradual decrease in temperature and lowering of the average temperature from the minimum thermal threshold, the flight activity of moths decreased and from mid-October onwards, the trap hunting stopped. The results also showed that the highest percentage of damage was related to the third generation and the lowest percentage of damage was related to the first generation L. botrana. It is recommended that the first specific spraying against grape clusters in the region for the second and third generations could be 5-7 days after the formation of the flight peak.

Spraying is one of the most important agricultural operations in protection stage. It should be prevented from immoderate application of these pesticides/herbicides, while weeds, pathogens and insects are controlled in this stage. Apparently, establishing an appropriate time for spraying operation, estimating the number of required and approved days for this operation as well as weather observations are quiet necessary to achieve this target. In this study, four limiting factors including rain, wind speed, temperature and relative humidity were considered for spraying operation and the approved ranges were determined accordingly. To data analysis, each month is divided into six Five-day sections. According to weather observations related to 24 years (1994–2018), the numbers of working days were determined within the appointed ranges, considering the limiting factors. T test is then employed to determine probable average ranges. Based on the results, among the limiting factors, temperature was the most effective factor to determine the number of working days for spraying operation. According to this, totally 11.9 days were appropriate for this operation in a crop season. In this regard, the total number of days for chemical control of thin-leaf and broad-leaf weeds, aphids, grasshoppers, bugs and Hadena basilinea were 17.9, 19.4, 21.2, 11.9 and 16.9 days in a crop season, respectively.

In this research the antiviral activity of medicinal plants including Weeping willow, Yarrow and Common Nettle ethanolic extracts against CMV-Fny infection in cucumber plant was explored under the greenhouse conditions. To this end, cucumber seedlings were mechanically inoculated with the CMV-Fny. The extract of the mentioned plants was added directly into the plants' rhizosphere at 200 ppm, 800 ppm and 1000 ppm concentrations. CMV-infection level in inoculated as well as young grown leaves was tested by DAS-ELISA in 3, 6, 9 and 12 days post-inoculation. Peroxidase (POX) enzyme activity was assessed for the cucumber seedlings which showed maximum virus inhibition at 12 days post-inoculation and the expression level of inhibitor of viral replication (IVR) gene was also examined by semi-quantitative RT-PCR (sq-RT-PCR) method for them at this time. ELISA results indicated that at 12 days after virus inoculation, CMV-Fny protein titer in inoculated and young grown leaves as well as disease severity index (DSI) decreased in cucumber seedlings treated with the plant extracts compared to the negative control. The most decreased level of CMV-titer observed 12 days at mature inoculated and young leaves by applying 1000 ppm concentration of nettle and 200 ppm of yarrow extracts. The expression level of IVR gene and POX enzyme specific activity increased in treated cucumber seedlings at 12 days post inoculation, represent a systemic resistance activity against CMV-infection, after extracts treatment.