和歌山県のカキ園およびカンキツ園の雑草におけるミカンキイロアザミウマとネギアザミウマの発生消長

Abstract

The western flower thrips, Flankliniella occidentalis (Pergande), and onion thrips, Thrips tabaci (Lindeman), cause serious damage to fruits of the ‘Tonewase’ persimmon when the fruit color turns yellow in early September. I investigated the seasonal abundance of the two thrips species on the various weed hosts in persimmon and mandarin orange orchards. Both F. occidentalis and T. tabaci overwintered on the biennial weeds such as chickweed, Lamium amplexicaule, and henbit, Stellaria neglecta. F. occidentalis showed two peaks in population density on weeds of orchards: one in May–June with the growth of biennial weeds and the other in July–August with the growth of annual weeds. Thus, the F. occidentalis population was shown to increase in association with the growth of wild plants. T. tabaci, on the other hand, had only one population peak in May, following the population continued to decrease toward the winter.