天敵温存植物としての障壁作物ソルゴーの評価：ソルゴーのフェノロジーがアブラムシ類（カメムシ目：アブラムシ科）の発生に及ぼす影響

To evaluate the role of sorghum as an insectary plant for predators attacking aphids, we investigated the seasonal occurrence of aphids on sorghums (Sorghum bicolor (L.) Moench), ‘Kazetachi’ (late flowering and a long culm, commercial cultivar), ‘Koutoubun’ (sweet sorghum, commercial cultivar) and ‘Akaamakibi’ (sugar rich, local variety) in 2007, varying the planting date. The aphid incidence started much earlier on the first two planting dates (25 April and 1 May) and aphids were significantly more abundant on ‘Kazetachi’, having peak abundance in middle to late August. In 2008, we investigated the seasonal occurrence of aphids on two cultivars, ‘Kazetachi’ and ‘Koutoubun’, planted on 15 April. Again significantly more aphids were found on ‘Kazetachi’, peaking in late July to early August with a high density of 1,500 individuals per leaf. During the survey in 2007 and 2008, Melanaphis sacchari (Zehntner) was predominant on sorghum irrespective of the cultivar. Our findings suggested that sorghums provide sufficient aphids as prey to aphidophagous predators and ‘Kazetachi’ is more suitable to be regarded as an insectary plant.