Differential Relative Abundance of Green-yellow and Red Forms of Myzus persicae (SULZER) (Homoptera : Aphididae) According to Host Plant and Season

抄録

The differential relative abundance of the green-yellow and red forms of Myzus persicae (SULZER) was investigated with respect to host plant species, part of the plant colonized and season by means of periodical sampling for 3 years on cabbages, radishes, potatoes and egg plants at Kyoto as well as occasional samples at Nobeyama (Nagano Pref.) and Sapporo. (1) The proportion of green-yellow aphids was highest on cabbages, lower on radishes, with the lowest proportion on potatoes throughout the growing period at Kyoto. Such differences in host plant were also found at Nobeyama and Sapporo. The proportion on egg plants was as low as on potatoes. (2) The proportion of green-yellow aphids on radishes was highest on the inner leaves, lower on the middle leaves and lowest on the outher leaves. (3) The proportion of green-yellow aphids increased on cabbages and decreased on potatoes towards summer, but no marked seasonal change was observed on radishes. The proportion of green-yellow aphids was higher in the spring-summer season as a whole than in the autumn-winter on both cabbages and radishes. (4) The facts revealed hitherto about the behaviour of the 2 colour forms were explained on the assumptions that the green-yellow and red forms differ intrinsically in the range of some chemical and physical requirements from their host plants and that the plant condition varies with species, part of the plant colonized and seasons.