Study On Occurrence Factors And Chemical Control Of Rice Bacterial Foot Rot In Zhejiang Provicne

Rice bacterial foot-rot disease is an important bacterial disease in China. Recently, this disease is increasingly serious and causes a dramatic yield loss of rice in some rice-growing areas of Zhejiang Province. The epidemiology knowledge of rice bacterial foot rot disease and effective bactericide is important to manage this disease. Therefore, effects of nitrogen fertilizer and planting patterns of rice foot rot disease were analyzed in this study. In addition, several kinds of available bactericide were screened by toxicity test and evaluated in fields. And resistance of rice varieties to this disease was analyzed. Detailed results were as follows:1. Effects of nitrogen fertilizer on rice foot-rot disease were analyzed, results showed that the incidence of this disease has become a rising trend with the increase of total nitrogen level. However, with the the increase of tillering nitrogen fertilizer, diseased plant rates were significantly reduced during the tillering stage of rice. And the occurrences of the disease had no significant difference among different basal nitrogen fertilizer levels and panicle nitrogen fertilizer levels, respectively.2. Effects of planting patterns on rice bacterial foot-rot disease were analyzed. Comparison test of direct-planting culture and transplanting culture in rice showed that the disease in the direct-planting field generally was less serious than that in those transplanting rice fields. Comparison test of different seeding ages by transplanting culture showed that young seeding by transplanter-transplanting culture and big seeding by hand-transplanting culture had a lower incidence rate. Thus, for controlling rice bacterial foot rot disease, young seeding should be transplanted by transplanters and big seeding by hands in production.3. A rapid virulence evaluation method of rice bacterial foot rot disease was established in this study.. Results showed that an optimized inoculation condition with a inoculation level at 1.4 x 107 CFU/mL and an inoculation time for 4 to 8 h was determined.. Resistance to rice bacterial foot rot disease of over 30 rice varieties were analyzed using this method, results showed that four varieties, including Yongyou538,Yongyou 8,Xiushui32,Zhong Zheyou 1,Qianyou0508 and Y Liangyou 1 had a relatively low incidence rate of rice bacterial foot rot disease, and they had a better resistance to rice bactetial foot-rot disease.4. The results of toxicity test showed that all tested bactericides had a certain degree of inhibitory effect on rice foot-rot bacteria. When treated with the recommended highest dosage of the tested bactericides,20% thiediazole copper SC,30% copper succinate+copper glutarate+copper adipate WP,20% Saisentong SC,20% bronopol WP and 3% benziothiazolinone WP had a stronger inhibitory effect on rice foot-rot bacteria. Results of a field experiment showed that the control effect of 3% benziothiazolinone WP reached to 73.71%. And the control effeffects of 20% Bronopol WP,3% zhongshengmycin WP and 20% thiediazole copper SC were also higher than 50%.