The Occurrence Rules And Control Measures Of Rice(Southern)Black-streaked Dwarf In Anhui Province

Rice black streaked dwarf disease and Southern black streaked dwarf disease are both serious viral diseases in rice production. The resistance of different kind of rice in Anhui province to the two disease were identified, the susceptible growth period of rice to black streaked dwarf disease and southern black streaked dwarf disease were explored, the yield loss model of Southern black streaked dwarf disease was set up, the chemical controlling measures to such disease were studied in this paper. Result is as follows:1. Make clear of the resistance levels of 44 main rice varieties (lines) in Anhui to rice black streaked dwarf disease and Southern black streaked dwarf disease.Resistance of the tested 44 varieties to black streaked dwarf disease were different as a whole, sometimes different distinctly. The resistance of indica rice to black streaked dwarf disease is weaker than that of japonica rice significantly. Among all the tested varieties(line), the following are of high resistance to rice black streaked dwarf disease:Ⅱ You ming 86, Kaiyou 8 and Liang you 688. The tested varieties with high resistance to southern black streaked dwarf diseaseis as follows:Hong liang you 166, Fu you 138, Liang you 827, Liang you hua 6, Y liang you 155, Wan dao 193, Wandao 161, Ⅱ you 8006, Liang you 688, Liang you long 340, Guofeng NO.1,2316S X 248, Fengyou NO.1, Ⅱ you 293, Liangyou4826, Ⅱ you 3216 and Wandao 191.2. Knowing well the susceptible growth period of rice to black streaked dwarf disease and Southern black streaked dwarf disease, the conclusion is as follow:The susceptible growth period of Feng lioang you NO.6 and Xing liangyou NO.6 to rice black streaked dwarf is from the three leaf to four leaf period; susceptible growth period to southern rice black streaked dwarf is in the three leaf period. 3. The yield loss model of Southern rice black-streaked dwarf disease was set up.No significant correlation was found between the severity and different incidence of rice black streaked dwarf disease. Meanwhile, the difference of average severity at different incidence rate is not significant (P=0.215, F=1.783), so the severity of the average value of 53.6%. The ratio of disease level from zero to four degree distribution is 364:11:12:8:5. The formula for the relationship between Disease level and the final loss rate is:y=2.553+49.355x-9.226x2 (R2=0.975) [y:loss rate, x:disease level (0-4)]4. Selected chemicals and control techniques to control Southern rice black streaked dwarf diseaseThe control effect of two application method of chemicals- soaking and spraying, and two matching approach-long-acting chemicals and quick acting chemicals on Southern rice black streaked dwarf were studied comparatively.The results showed that the control effect were better by using of the following mixedchemicals, Pymetrozine seed soaking with Pymetrozine spray, Pymetrozine thiamethoxam spray with Thiamethoxam oxazine spray, and Pymetrozine spray with chlorpyrifos Pymetrozine, reaching 60.78%, 68.64 and 70.59%, respectively. Separate use Thiamethoxam seed soaking, Pymetrozine seed soaking, Pymetrozine spray or chlorpyrifos spray, the controlling effects are worse, dropping to 37.25%,43.13%, 49.01% and 41.18%, respectively. Obviously, there are significant differences among the control efficiency of 3 kinds mixed and single approach of chemicals.