The Present Situation of Soybean Pest Management in Japan

Abstract

Soybean was cultivated in 140,800 ha with the total production of 197,300 tonnes (t) and the average yield of 1.40 t/ha in Japan in 1991. As pests on soybean 271 invertebrates (245 insect , 12 nematode, 7 Stylommatophoran, 5 mite, and 2 Isopod species), 9 birds, and 13 mammals including 2 rodents were recorded. Since the 1st October, 1991, 55 insecticides, 4 nematic ides, 3 acaricides, and a female-sex-pheromone product have been registered for controlling 22 groups of soybean pests (20 insect, a nematode, and a mite groups). Two to 4 frequency of insecticide applications are recommended, depending on pest situations in different regions and prefectures. Full time farm households follow to the recommendations but most part time ones apply commonly less than in recommendations and lose timely applications. Key pests are soybean podborer, aphids or dwarf, and beanfly in the north, stinkbugs, Limabean podborer, soybean podgallmidge, and tobacco leafworm in the central, and stinkbugs and tobacco leafworm in the south regions. The yield was frequently lost totally without insecticide application in south. The gross income/plant protection cost ratio was roughly estimated at 8–11 : 1 at the NARC in central Japan where pests and diseases usually are not very serious. Labour shortage was one of constraints for both full-time and part time farm households, especially in the south regions with low yields of 1.1–1.3 t/ha and average harvested areas of 0.07–0.18 ha/household.