Regulation Of The Occurrence And Control Of Rice Water Weevil(Lissorhoptrus Oryzophilus Kuschel)in Leping City Of Jiangxi Provience

The rice water weevil (Lissorhoptrus oryzophils Kuschel) is an alien insect pest whichinvaded in China in1988, mainly damanged rice.It was first founded in LePing city andWannian country in Jiangxi Provience.It now has spreaded to greater part areas of JiangXiprovience and has caused serious damaged. In order to direct the control of rice waterweevil, this paper invested the regularity of rice water weevil and the spatial distributionpattern of the overwintering generation adults,, studied the distribution in spring and thecorrelation coefficient of overwintering adults of RWW, assessed the effects of exogenousapplications of methyl jasmonic acid (MJA) on the resistance of rice plants to the ricewater weevil.The result showed that:1、The rice water weevil occurred two generations per year in double rice regions ofPoyang Lake plain of Jiangxi Province. The RWW began to come out from theoverwintering place when the temperature was over13℃, and continued to migrate in thefields. April15th was the fastigium of RWW came up out of the ground, April-end wasthe peak of adults migrate in the fields. The fastigium of fields adults occurred fromApril-end to early May. The final-term of overwintered adults was in early June.Adults of RWW ovipositioned and larvas hatched in May, the fastigium of larvaincubated in forepart and middle ten days of May. Pupa occurred from early June, andthe fastigium was in final ten days of June. The first generation adults emergencedfrom June, the fastigium was in the middle ten days of July. The final-term of the firstgeneration adults was in early August, a few adults stayed in the fields to form thesource of second generation in late rice season. The average field insects achieved22.95per100hills of rice in2011, loss percentage of rice was18%to20%; the insects in seriousplots achieved49.25per100hills, loss percentage of rice was30%-35%. The occurrencearea of Lissorhoptrus oryzophilus Kuschel in Jiangxi Province from2007to2010wasexpanded, the annual growth rate has a little declined than past. Adults of Lissorhoptrusoryzophilus Kuschel prefer feeding grimineae weeds.2、The relationship of quantity amount number of leaves with feeding scars byLissorhoptrus oryzophilus Kuschel with distance from overwintering site is significantnegative: Nst=-0.0641D+15.5，(R~2=0.5039，P=0.0144);The number of feeding scars onthe second cluster of rice near the ridge of field are positive correlation with the first.Ns2=0.3687Ns1+7.2937，(R~2=0.3625，P=0.0030)。The equations of total number of feedingscarss on leaves of weeds in weed quadrat associated with a variety of weeds:Y=-0.1528+0.0238*Sp2-0.5701*Sp5+0.3350*Sp7+2.3691*Sp10-0.3246*Sp12+0.6879*Sp14+1.4537*Sp15-1.5283*Sp18+1.5177*Sp19，(Y=ln(scar noT+1)，Spi=Proportion of weeds).It indicated that the feeding frequency of RWW is positive with the spieces of Gramineae plants.3、The spatial distribution pattern of the overwintering generation adults in fields ofthe RWW and feeding scars on late rice were aggregation distribution.4、The rice which was dealed with MJA will be insect resistant to adult RWW. In theearly period the number of RWW was decreased by the dealing concentration. In five daysevery area of adult RWW’s percentage was showed the adults transfer from highconcentrations plants to low concentrations plants which was treated by4differentconcentration methyl jasmonic acid (MJA).The amount and frequency of feeding of adultwhich were on rice seedlings was showed downward trend after be sprayed by4concentration of MJA solution, that is the length of single feedingscar was reduced by theincrease of concentration of solution. The larvae number was showed inversely correlatedby different dealing concentration which was compared with in library and field.