Influence of weather conditions on the initiation of spring flight of overwintered adults of Scirtothrips dorsalis (Thysanoptera: Thripidae) in a Japanese pear orchard in Chiba Prefecture
2019
Nakai, Z. (Chiba Prefectural Agriculture and Forestry Research Center, Chiba (Japan)) | Kawana, T. | Ohtani, T. | Shimizu, K.
We investigated the effects of abiotic environmental factors on spring flight initiation of Scirtothrips dorsalis Hood (Thysanoptera: Thripidae) by monitoring the number of its overwintered adults captured by yellow sticky traps in a Japanese pear orchard from 2012 to 2015. More S. dorsalis were captured on sticky traps placed at 50 cm above ground level in the plot where pear trees were dense than in the plot where trees were sparse, which suggests that many adults overwintered inside of pear orchards. More S. dorsalis were captured on traps placed at 50 cm above ground level than at 200 cm above, which suggests that sticky traps at 50 cm above ground level were suitable for monitoring the overwintered generation of S. dorsalis. A logistic regression analysis revealed that the capture probability (Pc) of overwintered adults was positively correlated with the daily maximum temperature and the hours of sunlight, and negatively correlated with the daily mean wind speed. More than 99% of S. dorsalis were captured when the maximum temperature exceeded 17.5℃, the mean wind speed was ≤ 2.7 m/s, or sunlight was ≥3.7 h/d. The date of peak capture of overwintered S. dorsalis could be estimated more accurately from the total effective temperature calculated from January 1 combined with the Pc value than from the total effective temperature alone.
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