Hymenopterous Parasitoids of the Rice Gall Midge, Orseolia oryzae (Wood-Mason) in the Maha Season in Sri Lanka

JARQ : Japan Agricultural Research Quarterly
ISSN 00213551
書誌レコードID(総合目録DB) AA0068709X
本文フルテキスト

Hymenopterous parasitoid species and their parasitism rates were investigated in paddy fields of 11 districts in Sri Lanka including 3 districts located in the dry zone from late December, 1991 to mid-January 1992 during the Maha monsoon season. The same surveys were conducted during the Yala monsoon season in 1989 and the dry season just before the Maha season in 1990. Following 4 species were collected during the current and previous surveys; Platygaster oryzae (Cameron), P. foersteri (Gahan), Neanastatus cinctiventris Girault and Obtusiclava oryzae Subba Rao. On the other hand, samples of Eurytoma sp. which were collected for the first time in Sri Lanka in 1990, could not be obtained during this survey. P. oryzae was widely distributed throughout all the climatic zones and the mean value of 21% for the percentage of parasitism, which was the highest among the 4 species was comparable to that recorded during the previous surveys. Mean percentage of parasitism of P. foersteri was about 1%, next to that of the former species. The percentage of parasitism of these 2 parasitoid species decreased from the wet zone to the dry zone. For example, the percentage of parasitism of P. oryzae was about 31, 20 and 3% in the wet, intermediate and dry zones, respectively, presumably due to the difference in the population density of the rice gall midge in these zones. Namely, the rice gall midge may maintain higher population levels in the wet zone where rice plants are cultivated twice in rain-fed paddy fields during the Yala and Maha monsoon seasons due to the larger amount of precipitation than in the other zones.

刊行年月日
作成者 Masahiro KOBAYASHI Chandrasiri KUDAGAMAGE
オンライン掲載日
国立情報学研究所メタデータ主題語彙集(資源タイプ) Journal Article
28
2
開始ページ 112
終了ページ 116
言語 eng

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