Studies On Monitoring And Intergrated Management Strategy Of Resistance To Insecticides In Chilo Suppressalis (Walker) In JiangSu Province

Striped stem borer (SSB), Chilo suppressalis (Walker), is one of major insect pests of rice in Jiangsu Province. Since late-1990s, with cropping system reform, rice varieties substitution and insecticide resistance development, population of this pest and its damage to rice increased dramatically, severely threatening the high and stable yields of rice. Insecticide resistance in C. suppressalis has become an important subject in rice protection of the Province. To improve the management of resistant SSB, insecticide resistance was, agricultural and chemical control methods studied, IPM strategy and tactics, and large scale demonstration conducted in Changshu City.In 2002, resistance of the striped stem borer, to four insecticides (representing 4 major classes of insecticides) was surveyed with 12 populations collected from 10 counties (includingchangshu,xishan,wujin,jurong,jiangyan,gaoyou,chuzhou,suyu,guany lianyungang city)in Jiangsu Province. Different level of resistance to monosultap(an analog of nereistoxin) was found in all populations tested. populations collected from south Jiangsu were more resistant than those from north, with that from Changshu City being the most resistant(16-fold). Low level of resistance to triazophos was detected in populations from south Jiangsu (4.5- to 7.4-fold), yet the others remained susceptible. No fipronil or abamectin resistance was detected.Percent damaged bunches and percent damaged plants caused by 1~st generation of SSB in Taihunuo (a variety with big ear) were 3.33% and 0.61%, respectively, significantly greater than those in non-big-ear variety 2105(0.28% and 0.03%, respectively). Two years' trial showed that hybrid japonica and rice varieties with tall stem and big ear were key targets in SSB control.The effect of rice planting date on occurrence of SSB was studied in 3 consecutive years. In Changshu area, there would be 71.15% or 86.93% less SSB infestation if rice is sowed on May 20 or May 25 other than on May 10. No adverse effects on yield were foundin experiment with Wuyunjing 7, provided it is sowed before May 20.More than 30 insecticide formulations were tested by field plot trials in 3 different years. A dozen of formulations belong to four types were screened out as high effective insecticides for SSB control, i.e.: Type A (Regent, triazophos, phenthoate), Type B (triazophos-containing mixtures, Duzuolin, Dingzuolin, Fuzuolin, Shamingzuo, etc.), Type C (trichlorfon-containing mixtures, Dudi, Dikui, Dizuolin, etc.), and Type D(biorational insecticides such as Shasu and Lulang).Plot trial and demonstrating trial application showed that rice seed treatment with fipronil either by immersion or dessing can effectively control 1~st generation of SSB in both seedling bed and growing field.Covering >10 hm~2 large scale demonstration of SSB integrated management was conducted in Villa Wuxin, Dayi Town, Changshu City. The strategy of "to postpone rice sowing and transplanting date appropriately as a prerequisite, to use highly effective insecticides as an important factor, and to control 1st generation of SSB in both seedling bed and growing field heavily and completely as a key" was proposed and applicated in the zone. Insecticide application was reduced by one times in demonstration zone compare with that outside. In demonstration zone, SSB has been effectively controlled, with percent damages by 1st generation of SSB <0.15% and moth number under light trap being 45 in 2004. In addition, resistance determination showed that resistance to monosultap in SSB from the zone decreased a little, and that to triazophos remained within low level.By means of inspection of the scene, exchange meetings and so on, the successful technology of SSB management had generalized to many rice growing areas south and along the Changjiang River, with a sum of area about 200 million 667m2*times.