Due to the reformation of cultivation system and shift of rice varieties in Huainhe and Yangtze river rice areas in recent years, and partly populatin of the fourth generation Cnaphalocrocis medinalis (emergence on late-Oct.

In 1992 - 1993, investigations on the compositions and structures of insect communities, mainly wheat insect pests and their natural enemies, in three different cropping systems associated with wheat , namely, wheat monoculture,wheat interplanted with rape and wheat interplanted with cotton were systematically carried out in Xiuwu County,Henan Province.

In 1997 ~ 1998, investigation on the compositions and structures of insect communities, mainly insect pests and their natural enemies, in three different cropping systems associated with maize, namely maize monoculture (MM), maize plastic-culture (MPC) and maize interplanted with wheat (MIW) were systematical carried out in Zhangye County, Gansu Province.

Hokowase is a better variety for controlled cultivation.

The results showed that the yield under double cropping system was 78% higher than single cropping system,and the quality was good as well,and this pattern could be widely implemented in the areas with lower altitude and latitude.