| The EC50 of Amistar ranged from 2.18μg·mL-1 to 7.96μg·mL-1in 91 Heilongjiang strains by mycelium growth rate method, and the results showed that the sensitive base to Amistar was4.64μg·mL-1, the resistance index ranged 0.46962.4434. and all of the tested strains were sensitivity. The sensitivity dominated 4.06.0μg·mL-1 in rice-growing areas of Heilongjiang Province from N44°35′to N46°36′. Spore research of 10 strains chosen at random showed that 60% strains'sensitivity were obvious with Amista 4.64μg·mL-1 and inhibition ratio was more then 50%. The conidia germination inhibition rate ranged from 35.33% to 43.73%. The control experiment of Tricyclazole, and Amistar showed that Amistar(EC50)was higher than Isoprthiolane,lower than Tricyclazole.The EC50 of Azoxystrobin ranged from 0.116μg·ml-1 to 0.797μg·ml-1 in 91 Heilongjiang strains by mycelium growth rate method, and the results showed that the sensitive base to Azoxystrobin was 0.4370μg·mL-1, the resistance index ranged 0.26641.8240 , the spore inhibition rate was more than 50%and Inhibition spore germination rate ranged from 44.77% to 59.15%. The average EC50 values (0.6046μg·mL-1)of spore germination was higher than the one of hypha growth. Azoxystrobin could make certain inhibition effect on the formation of melanin with a combined application method of azure A, but it was unobvious. The resulted revealed that the highest inhibition rate was 56.96% when Azoxystrobin concentration was 1.2μg·mL-1, the highest inhibition rate was 62.03% when Azoxystrobin concentration was1.5μg·mL-1. Consecutive cultivation of 4 strain generations in Azoxystrobin higher concentration showed that:the sensitive was stability; the resistance index ranged from 0.790 to 1.148,but there were some difference in the tested strains. The tested strains by ultraviolet mutagenesis did not obtain the mutations. There were 4 mutations which was obtained by chemical mutagenesis of higher concentration. The EC50 of mutations ranged from 0.327μg·mL-1 to 0.661μg·mL-1,and all of the mutations had were sensitive.Synergy effect of Azoxystrobin and SHAM was determined by mycelium growth rate method, the sensitivity of tested strains the sensitive declined 23.56%, but there were some difference in the tested strains. All over the tested strains , 78.02% strains showed synergy and 31.87% strains showed synergy obviously(F≥1.5). Synergy effect of Azoxystrobin and SHAM was not obvious in the inhibition of spore, FZYH,HGDH-5 and ZYWD had synergy(F:4.94,2.26 and1.881.5). The resulte showed synergy obviously on resisting blast melanin synthesis. In addition to FJCY, 9 strains'inhibition rate increasd by6.9530.18%, and there were 5 strains showed synergy obviously(F≥1.5). Consecutive cultivation of 4 strain generations in Azoxystrobin-SHAM higher concentration showed that:the sensitive was increased obviously. Among 4 mutations that IPTr-BYYF-2 and IPTr-FJJQ-4 had lower synergy effect; IPTr- BQBE-1 and IPTr- SHAA-3 had higher synergy effect. |
