The effect of cover crops in reducing the damage of potato tuber moth, Phthorimaea operculella (Zeller) on potato tubers at the end of the growing season in the field

Potato tuber moth, Phthorimaea operculella (Zeller), is the most important pest in potato fields in the world and Iran. The use of appropriate agricultural and protection strategies to prevent oviosition of Ph. operculella on newly formed potato tubers at the end of the cropping season can be effective in reducing its damage. The effects of cover crops on damage reduction on newly formed potato tubers were investigated in a randomized complete block design with three replications during two years 2020 and 2021. After the senescence of potato foliage, the cover crops including of vetch (Vicia sativa), grass pea (Lathyrus sativus), rye (Secale montanu), and strengthening of the natural field vegetation were used as cover crops in the field. Tuber infestation (%) during two years in vetch, grass pea, reinforcement of field vegetation and rye was 8.00, 12.33, 26.33 and 26.17%, respectively and all treatments significantly reduced the damage on potato tubers when compared with control (39.17%). The number of larvae in the infested tubers showed a significant difference between treatments, and the treatments of vetch, grass pea, reinforcement of field vegetation and rye showed a lower larval density, respectively. Based on results, vetch is the most effective plant to cover the soil and prevent Ph. operculella oviposition on the potato tubers. Moreover, maintaining and strengthening of weeds in the field at the end of the growing season and after the drying of potato foliage could be a low-cost method to prevent damage by Ph. operculella on tubers in the soil.