| Guangxi is the largest producing areas of sericulture, mulberry Sclerotinia is one of the major diseases of mulberry.With the great development of sericulture, the planting area of mulberry are expanded every year. Meanwhile, industry group of mulberry with characteristics has shaped up. However, occurrence and damage of mulberry sclerotinia have increased years by years, which has become a serious threat to mulberry production and development and also becomes an obstacle to industrial development. This paper analyzes the ordinary drug used to prevent and treat mulberry sclerotinia according to study rules of mulberry sclerotinia incidence and pathogen infection. It studies on indoor bacteriostatic and field efficacy for 70% thiophanate-methyl having effect on mulberry pathogen Sclerotinia, analyzes population dynamics of mulberry field after applying thiophanate-methyl, and also explores the interval safety period of thiophanate-methyl leaving on mulberry and leaves. This paper provides preliminary reference for the safety evaluation on preventing sclerotinia mulberry when using thiophanate-methyl in the future. The study results are as follows:First, through the result of inhibition test, it is obvious that 70% thiophanate-methyl WP, 80% carbendazim WP and 80% Chlorothalonil WP have inhibitory effects on mulberry sclerotinia bacteria. Among these,70% thiophanate-methyl WP have the best inhibitory effect. The inhibition rates of using 70% thiophanate-methyl WP 600,800 and 1000 reach 79.01%, 72.26% and 66.04% respectively, which WP600 has the best inhibitory effect. Considering the above results, it is indicated that 70% thiophanate-methyl 600-1000 have inhibitory effects on mulberry sclerotinia bacteria.Second,70% thiophanate-methyl WP600-1000 have great effect on preventing mulberry sclerotinia according to the result of inhibitory test. After investigating the incidence, we can learn that the control effect of 70% thiophanate-methyl WP 600-1,000 are 97.26%,98.06% and 99.79% respectively. From the perspective of control effect,70% thiophanate-methyl WP 1,000 has the best control effect on preventing mulberry Sclerotinia, which control effect is 99.79%.Third, according to the result of test on thiophanate-methyl residues in mulberry and the maximum value of Japan’s Food Safety residue on fruits and tea positive, the standard (MRLs=3mg/kgã€MRLs=10mg/kg) of 70% thiophanate-methyl 600 and 800 residue in mulberry and leaves safety interval are 28d and 14d, while 1000 is respectively 14d and 7d. Referring to China’s food safety standard, the maximum value of Thiophanate-methyl in the fruit takes the minimum of MRLs (2mg/kg) as reference. The safety interval period of 70% thiophanate-methyl 600 and 800 in mulberry is 28d, while 1000 is 21d. On the basis of the European Food Safety, the maximum residue standard of fruit and tea affected by Thiophanate-methyl is MRLs=0.1mg/kg.70% thiophanate-methyl 600 to 1000, the safety interval period in mulberry and leaves is larger than 35d.Fourth, Based on indoor antibacterial test, field control test and the safety test of thiophanate-methyl in mulberry, it is concluded that the plants should be continuously sprayed 70% thiophanate-methyl 1000 at interval of 7d in every three time. It is the best method to control sclerotinia in the temperature above 15℃ and at the beginning period of flowering. According to Japan’s food safety standard, it is recommended that the safety interval periods of the maximum residue to better control methods in mulberry and leaves are 14d and 7d. On the basis of Chinese food safety, the maximum residue of thiophanate-methyl should be limited in the minimum standards MRLs. It is suggested that the safety interval period of better controlling methods in mulberry is 21d. Referring to EU’s food safety standard, the maximum residue should be limited. It’s safety interval period of controlling methods in mulberry and leaves is more than 35d. The specific time need further study. |
