| Objective: To systematically investigate the occurrence regulation of pepper(Capsicum annuum L.)powdery mildew and virus disease in Yanqi reclamation region in Xinjiang, screen safe pesticides which have better control effects on pepper virus disease, powdery mildew and root rot in Xinjiang and provide theoretical basis and technical support for preventing and controlling main pepper disease in Yanqi reclamation region in Xinjiang.Methods: Correlation analysis on climate condition, aphids and pepper virus disease occurrence were made. Correlation analysis on climate condition and pepper powdery mildew occurrence were also made to figure out the pepper virus disease and powdery mildew regulation in Yanqi reclamation region. Indoor tablet confrontation culture and mycelial growth inhibition method were used to determine the poisonous force and inhibition rate of each reagent on pepper root rot fungus hypha. Field spray or indoor pot experiment method were used to determine the prevention effects of each germicide on pepper virus disease, powdery mildew and root rot.Results: 1. Pepper virus disease occurred in late May, it rapidly developed from late June to late July and reached the peak from early of August to late September. It was advantageous to the pepper virus disease when the average temperature was 20℃ to 25℃. Increasing rainfall on the stage of fast growth would restrain the number of aphids and inhibit the virus disease occurrence. The accumulative rainfall was positively correlated with the virus disease. The occurrence peak of aphids basically coincided with the rapid development period of disease. Aphids were important transmission mediators of pepper virus disease in Yanqi reclamation region. The 6% oligosaccharides 400 times liquid were sprayed at the beginning of virus disease occurrence, the defensive efficiency could reach 80.16% after the second spraying two weeks,and it produced no phytotoxicity. The control effect was significantly higher than the other three pesticides.2. Pepper powdery mildew occurred from the middle of July to late September. It occurred in the middle of July and reached the peak from the end of August to early September. The disease rapidly developed from early August to the middle of August. Temperature and humidity were the basic factors affecting the disease. It was good for disease development when the average temperature was 20℃ to 25℃,which was significantly positively related to the disease growth rates, whereas correlation coefficient between relative humidity in the field and the disease growth rates was-0.645, which showed significantly negative correlation. High relative humidity in the field was bad for the powdery mildew occurrence. The correlation coefficient between relative rainfall and the illness growth rates was-0.398. A moderate amount of rainfall at the early stage of disease was beneficial to the powdery mildew occurrence, but rainfall in the later period was not conducive to the spread and occurrence of powdery mildew. The control effect of the10% difenoconazole WG was the best, its control effects of 1000 times, 2000 were 95.65%, 89.54%respectively; The control effects of 2000 times of 50% Kresoxim-methyl WG, 1000 times of 250grams/liter pyrazole ether ester EC,100 times of 2% wuyi rhzomorph AS, 1000 times of 300 grams/literether bacteria SC and 100 times of the bacillus subtilis S44 strain SC were 88.23%, 84.55%, 78.69%,75.42% and 58.85%, respectively.3. All eight kinds of pesticides inhibited the pathogenic bacteria of pepper root rot. Agent EC50 size from big to small was as follows, pyrimidine nucleoside antibiotic AS, ethylicin EC, azoxystrobin WG,general pervez musharraf held carvacrol AS, difenoconazole WG, phenazine-1-carboxylic acid SC,prochloraz·Chitosan EW. Among these agents, prochloraz·Chitosan EW was only 0.004 mg/L, which was significantly lower than the other six pesticides. The suspension inhibition rate of the bacillus subtilis S44 strain on F.oxysporum was 41.67%. Indoor pot experiment results showed that the control effect of 80%ethylicin EC 400 times was 81.5%, which was significantly higher than the other three pesticides and had significant differences with others.Conclusion:1. Myzus persicae was the main transmission mediators of pepper virus disease. Temperature,humidity, rainfall, accumulative rainfall and other factors could affect the populations of Myzus persicae,which had an important influence on the virus disease occurrence. This study showed that the control effect of 6% oligosaccharides AS 400 times on pepper virus disease was 80.16% after the effective prevention and control of aphids population, which could be the main pesticide to prevent and control pepper virus disease in Yanqi reclamation region and could also be used interchangeably with ningnanmycin, hydroxyl olefinic· moroxydine and moroxydine· cupric acetate monohydrate.2. Temperature, humidity and rainfall had an important influence on pepper powdery mildew. The10% difenoconazole WG 1000, 2000 and 3000 times were recommended to control the pepper powdery mildew in Yanqi reclamation region, and they could also be used interchangeably with 2000 times of 50%azoxystrobin WG and 1000 times of 250 grams/liter pyraclostrobin EC.3. Indoor toxicity measurement and pot experiment results showed that 80% ethylicin EC 400 times liquid was the best pesticide to control the pepper root rot. |
PDF Full Text Request