Study On Occurence Of Laodephax Striatellus Of Rice In Liaoning Province And Effect Of Chemical Control Method

Although Laodephax Striatellus of rice has been existed in the most of the places of North and South China for many years, it has outbroken in Liaoning only for these two years. Much experience also has been analysed, but prevention and control on the Laodephax Striatellus of rice in Liaoning is quite different from those in other places because of such reasons as weather, planting structure, way of cultivation, crop varieties and so on. The current study is based on the production of rice in Liaoning province, a great many field experiments have been carried out and medicament which is suitable for the rice of Liaoning has been selected. The effective way of prevention and control on the Laodephax Striatellus of rice is significant in the rice production guidance, promotion of agricultural efficiency and peasants' income. The study found that:Laodephax Striatellus only occurred for very few times in Liaoning province before 2006. Since the outbreak in 2006 to the year of 2009, the area and amount of Laodephax Striatellus in Donggang, Panjin and other places in Liaoning have been increased year by year and cause serious threat to the production of rice in our province. Since prevention and control were carried out efficiently and the weather cause little amount of relocation of insects, Laodephax Striatellus didn't outbreak in large area.Based on the detection of the infection rate for two years, the samples of overwintering striatellus, collected in the main rice producing areas in Liaoning, contain some certain infected individuals. The infection rate in different places in the year of 2007:5.7% in Liaozhong county,22.2% in Pu Landian, 9.3% in Haicheng,15.9% in Donggang,7.5% in Linghai,5.26% in Da Shiqiao,12.5% in Liaoyang county,5% in Tieling county,3.3% in Dawa county and 1.7% in Panshan county, among which the samples of Laodephax Striatellus collected in Panshan has the lowest infection rate which is 1.7%; the samples collected in Pu Landian has the highest infection rate which is 22.2%. The infection rate in different places in the year of 2010:2.9% in Linghai,28.6% in Dawa Gaojia,3.5% in Haicheng,2.4% in Xinmin and 6% in Donggang.There is no signifiant correlation between the amount of Laodephax Striatellus and the rate of Rice stripe disease, but there is significant correlation between the rate with worm and morbidity, and there is signifiant correlation between morbidity and the multiplication of the rate with worm and the infection amount. Therefore, the prevention and control on the Laodephax Striatellus play a key role in decrease the infection rate of rice stripe disease.Medicaments suitable for our province in prevention and control on the Laodephax Striatellus are: 25% of buprofezin WP,40% of chlorpyrifos EC,25% of thiamethoxam DC,80% of dichlorvos EC.The best time for prevention and control on the Laodephax Striatellus of rice is the time of young nymphs (2-3 instars).In order to prevent the resistance of Laodephax Striatellus, these medicaments should be used by turns.