Studies On The Biology And Control Of Chilo Suppressalis In Harbin Region

Studies on the Biology and Control of Chilo suppressalis in Harbin RegionAbstractAsiatic rice borer Chilo suppressalis(walker), belongsto:Lepidoptera, Pyralidae and its other names are stalk gnawing worm, stalk core biter, etc. Chilo suppressa]ic has a wide host scope, and can harm rice, wild rice, sugar-cane, wheat, corn, bean, rape and other crops,and millet grass, Li's grass and other weeds. Chilo suppressalis has a wide distribution,and it can be found in Japan, Philippines, Vietnam, Thailand, Malaysia, India, etc. It has a wide distribution at home,too,nainly in the eastern and middle parts of China. It can have a serious effect on the output of rice,and produce different forms of harm in different stages of growth,such as withered sheath,withered stalk core ,withered ear,seedless ear,worm hurt stalk,etc.,with withered stalk core and seed less ear of the greatest harm. In 1998, Chilo suppressalis was first found and its damaged occurred in the fields of Acheng and Wuchan towns of Harbin region,and in 2001 the damaged area was 960,000 kin2,making up 37% of the ricepl anting area of Harbin city,with the loss of about 47 million RUB yuan. Owing to failing to timely and effectively take prophylactic nteasures,the economic loss was great,and the high- poisonous agricultural pesticide and large quantities of ester agricultural pesticide were applied to rice fields,which polluted rice seedsas well! as seriously spoiled the ecological environment of water fields.This not. only endangers the people's health, but also becomes one of the largest obstacles to the export of rice in our city after China joins into WTO. In this paper a systematic research of the biological character 1st ics and control of (7biIo sUppr(?ss~1I is was miiile in Ilarb iii rug i (.)rI by i rivest i ga t i ,ig t lie harm ofthe Chilo suppressalisin fields synchronously with testing worms under the manual indoors control.The research result shows:1 Chilo suppressalis completely Changes its form,and one generation forms for each year in our city. The peak putation period is in the first and second ten days of June,and the pupa period is about 10.9 days.The peak period of the adult worm emergence is in the second and third ten days of June,with the average hf e of 2 -7 days. The peak period of oviposition is in the third ten days of June, a nd the oviposition period is about 5 '--7 days.The peak period of young worm hatching is in the first ten days of July,and the field investigation continued until the middle of the first ten days of July. Young worms eat rice leaf sheathes and stalks until the second and third then days of September, and begin to spend win ter in stalks and roots of rice.2 The young worms of Ghilo suppressalis have the habit of living in gourps and making haruts.After the young worms are hatched, they enter the leaf sheaths in the lower part of the plant piece near the water sufrace and make harms in gro ups, when the length of the body of the yound worms living in groups is 3 6 mm.Chilosuppressa]is has a habit of making harms from piece to piece. The adult worms have an obvious tendency of phototactic move,ent,and they hide during the d ay and caine out at night.The adult worms have a strong tendency of phototacitc movement for black light lamps,and a certain tendency of phototactic movement for high voltage mercury lamps.3 Ghilo suppressalis has different harms for different strains of rice,with an obvious difference in the harmed piece rate and withered stalk core and seed less ear rate of rice.The rice strains which grow luxuriantly,with thin stalks a nd ripen later,are most seriously affected.Among the rice strains mainly planted in our region, Dong Nong V-7, Dong Nong V 10, Five best rice No. I and Fuji No. 1 a re seriously affected,and Korean rice is less affected.4 The withered stalk core, withered ear and seedless ear have thehighest effect on the output of rice.The field investigation shows that, the higher the withere dstalk core rate and the seedless ear...