ISSN 1392-3196 / e-ISSN 2335-8947
Zemdirbyste-Agriculture, vol. 107, No. 2 (2020), p. 139–146
Changes in Sitona lineatus abundance in faba beans as influenced by the air temperature and rainfall in the three decades
Mohammad ALMOGDAD, Kęstutis TAMOŠIŪNAS, Roma SEMAŠKIENĖ
This research was carried out at the Institute of Agriculture, Lithuanian Research Centre for Agriculture and Forestry during the growing seasons of 1985–1988 and 2017–2018. The aim of this study was to analyse the changes in pea leaf weevil (Sitona lineatus L.) abundance in faba bean as affected by the air temperature and rainfall over the past more than 30 years. To collect adults of S. lineatus, yellow water traps were used during the growing season in both study periods. Larvae were counted in root nodules and in the surrounding soil. To determine the foliar damage, automatic leaf area scanner was used in 1985–1988, while in the second experimental period foliar damage was estimated by counting the number of U-shaped notches on leaves. The results showed that the trend of temperature maximums and minimums increased during three decades, and the amount of rainfall was uneven through the years. The increase in average air temperature was rapid in the recent three decades, which resulted in the change in the day-degrees required for S. lineatus. In the present study, the recorded accumulative thermal units over the two periods from 1985 to 1988 and from 2017 to 2018 showed a rise in day-degrees. The pyrethroid treatment was significantly effective against foliar damage, but it was ineffective in reducing the number of larvae and damaged nodules compared to the untreated.
Further research on the bioecology of S. lineatus and on the effective timing of its control is needed in Lithuania. The results obtained in this study supplement the already existing agricultural practices aimed at improvement of pea leaf weevil management in faba bean.
Key words: day-degrees, pea leaf weevil, pyrethroides, root nodules, Vicia faba.
Full text: 107_2_str18.pdf