From field investigations and inoculations, Dothistroma pini, the pathogen of Dothistroma needle blight was found to overwinter as mycelium and unmaturcd accrvuli in infected needles. The conidia were sprcadcd mainly ...From field investigations and inoculations, Dothistroma pini, the pathogen of Dothistroma needle blight was found to overwinter as mycelium and unmaturcd accrvuli in infected needles. The conidia were sprcadcd mainly by rain splash. The disease became widespread by transporting diseased seedlings and scions, conidia spread throughout the growing season, but mainly from May to July. The disease was found in both stand locations in each summer of investigation. The outbreak severity was serious in pure stands of susceptible pine and mixed stunds with large components of susceptible pine, but slight in mixed stands of unsusceptible species with small components of susceptible hosts. The disease was less severe in pruned stands than in unpruned stands. The disease was most serious near the infection centre. indoor and outdoor tests, it was shown that Chlorothalonil smoke, Chlorothalonil spray and Thiram and Asomate sprays were effective control fungicides.展开更多
The indoor toxicity determination for several chemicals were carried out on Septoria pini-putmlae andDothistroma pini. The resutts showed that Carbendazol, Zineb and Thiophanate-methyl had better effect of killingthe ...The indoor toxicity determination for several chemicals were carried out on Septoria pini-putmlae andDothistroma pini. The resutts showed that Carbendazol, Zineb and Thiophanate-methyl had better effect of killingthe fungi. The field experiment indicated that Zineb wettable powder with concentrations of 1:200, 1:300 and 1:500had 79.2%, 67.2% and 59.7% control results respectively. The control results of 1:200 Carbendazol wettable powder and 1:200 Thiophahate-methyl wettable powder were 67.7% and 67% respectively.展开更多
Fixed quadrates were established in different stands. In continued six years, the occurring period, occurring amounts and the relation between epidemic disease and environmental factors were investigated according to ...Fixed quadrates were established in different stands. In continued six years, the occurring period, occurring amounts and the relation between epidemic disease and environmental factors were investigated according to spraying lawsof spores and accounting measures of disease ranking. The occuring peak period of the disease was from the last ten days ofMay to the second ten days of June. The epidemic period was from the last ten days of June to the second ten days of Julyand the initial decease period was from the last ten days of July to the beginning of September. The change of the diseasedepended on air temperature, relative humidity and precipitation. A multiple linear regression model was established usingcomputer, which can predict the disease index(Y) of 10 days later, with more than 95% reliability展开更多
The spatial distribution pattern of needle bright disease was mathematically studied. The results showed that it is tally with negative binomial distribution. The infected area and damaged amount can be forecasted wit...The spatial distribution pattern of needle bright disease was mathematically studied. The results showed that it is tally with negative binomial distribution. The infected area and damaged amount can be forecasted with this spatial distribution pattern. Through the study on probability distribution of spatial points for single tree, the method and equations for calculation of the disease index of whole forest belt were determined.展开更多
文摘From field investigations and inoculations, Dothistroma pini, the pathogen of Dothistroma needle blight was found to overwinter as mycelium and unmaturcd accrvuli in infected needles. The conidia were sprcadcd mainly by rain splash. The disease became widespread by transporting diseased seedlings and scions, conidia spread throughout the growing season, but mainly from May to July. The disease was found in both stand locations in each summer of investigation. The outbreak severity was serious in pure stands of susceptible pine and mixed stunds with large components of susceptible pine, but slight in mixed stands of unsusceptible species with small components of susceptible hosts. The disease was less severe in pruned stands than in unpruned stands. The disease was most serious near the infection centre. indoor and outdoor tests, it was shown that Chlorothalonil smoke, Chlorothalonil spray and Thiram and Asomate sprays were effective control fungicides.
文摘The indoor toxicity determination for several chemicals were carried out on Septoria pini-putmlae andDothistroma pini. The resutts showed that Carbendazol, Zineb and Thiophanate-methyl had better effect of killingthe fungi. The field experiment indicated that Zineb wettable powder with concentrations of 1:200, 1:300 and 1:500had 79.2%, 67.2% and 59.7% control results respectively. The control results of 1:200 Carbendazol wettable powder and 1:200 Thiophahate-methyl wettable powder were 67.7% and 67% respectively.
文摘Fixed quadrates were established in different stands. In continued six years, the occurring period, occurring amounts and the relation between epidemic disease and environmental factors were investigated according to spraying lawsof spores and accounting measures of disease ranking. The occuring peak period of the disease was from the last ten days ofMay to the second ten days of June. The epidemic period was from the last ten days of June to the second ten days of Julyand the initial decease period was from the last ten days of July to the beginning of September. The change of the diseasedepended on air temperature, relative humidity and precipitation. A multiple linear regression model was established usingcomputer, which can predict the disease index(Y) of 10 days later, with more than 95% reliability
文摘The spatial distribution pattern of needle bright disease was mathematically studied. The results showed that it is tally with negative binomial distribution. The infected area and damaged amount can be forecasted with this spatial distribution pattern. Through the study on probability distribution of spatial points for single tree, the method and equations for calculation of the disease index of whole forest belt were determined.
