بررسی اثر آفتاب دهی خاک و آبیاری بعد از کاشت بر میزان آلودگی بنه‌های زعفران به کنه‌ی Rhizoglyphus robini Claparède و اندازه و تعداد بنه زعفران

In this study, 30-day solarization effect by transparent plastic (In July 2011) along with irrigation after cultivation was evaluated on the percentage of bulb mite infestation and the size and number of saffron bulbs (Corcus sativus L.). Saffron was cultivated in June 2012 and the experiment was carried out as split plot based on randomized complete block design with three replications during 2012-2014 in Gonabad, Khorasan Razavi province, Iran. Solarization and non-solarization treatments before planting were placed in the main plots and three treatments including without irrigation after cultivation, irrigation immediately after cultivation and irrigation 45 days after cultivation was placed in sub plots. The results showed that the size of the saffron bulbs had no correlation with the percentage of mite infestation on bulbs at the 0.05 level. There was a significant decrease in saffron mite infestation in solarization treatment. The effect of irrigation after cultivation was also significant on the percentage of mite infestation. Accordingly, the lowest percentage of infestation was obtained in “solarization+without irrigation” treatment (0.29±0.04) and the highest percentage of infestation in “non-solarization+irrigation immediately after cultivation” treatment (4.75±0.11). Increase by 4.612 times of the infestation ratio of saffron mites was observed in irrigation immediately after cultivation treatment compared to the treatment of without irrigation after cultivation. This increase could be due to the increase in soil moisture and inactivity of the saffron bulbs in June, which will lead to the growth of saffron mite. Moreover, results showed that solarization treatment had no significant effect on the size and number of saffron bulbs during the crop period but irrigation treatment affected size and number of bulbs. Accordingly, the highest percentage of weight and number of saffron bulbs (per half-square meter) was observed in irrigation treatment immediately after cultivation (60.44±1.44 and 39.17±1.97) and irrigation 45 days after cultivation (61.84±0.42 and 41.64±1.09). Finally, “solarization+without irrigation” treatment was desirable because of the lowest percentage of saffron mite infestation. Also, because of the highest percentage of weights and the number of saffron bulbs, “solarization+irrigation 45 days after cultivation” treatment was proposed.