Evaluation On The Effects Of Several Foreign Chemical Fungicides To Control Botyosphaeria Berengeriana De Not.f.Sp. Piricola

To solve the current problems of Botyosphaeria berengeriana de Not. f. sp. piricola on resistant to traditional fungicides, bio-assay tests were made for eight fungicides against Physalospora piricola in laboratory. These fungicides included 70% propineb wettable powder, 10% difenoconazole water dispersible granules, 250g/L azoxystrobin suspension concentrate, 500g/L iprodione suspension concentrate, 430g/L tebuconazole suspension concentrate, 70% metiram dry flowable, 400g/L flusilazole suspension concentrate, 50% kresoxim-methyl dry flowable. 70% mancozeb wettable powder was used as check. In addition, field tests of these fungicides with different concentration were made to control the disease on apple trees.The results showed that except 50% kresoxim-methyl dry flowable, the effects of other fungicides expressed stronger inhibitory effects against mycelium growth than 70% mancozeb wettable powder.10% difenoconazole water dispersible granules showed the highest toxicity with EC50 of 0.017μg/mL, followed by 430g/L tebuconazole suspension concentrate and 400g/L flusilazole suspension with EC50s of 0.114μg/mL and 0.393μg/mL respectively.In the field tests of 2008, 250g/L azoxystrobin suspension concentrate at the concentration of 800 times was the best with control effects of 85.5% on branches, 92.39%, 100% and 98.59% on fruits at harvesting time, 15 days and 30 days during storage respectively. In the field tests of 2009, 250g/L azoxystrobin suspension concentrate at the concentration of 800 times was also the best with control effects of 88.58% on branches, 89.68%, 98.41% and 96.72% on fruits at harvesting time, 15 days and 30 days during storage respectively. The second best fungicide is 10% difenoconazole water dispersible granules at 1500 times concentration with control effect of 82.00% on branches, 90.78%, 91.13% and 95.76% on fruits at harvesting time, 15 days and 30 days during storage respectively. In the field tests of 2009, 10% difenoconazole water dispersible granules concentrate at the concentration of 1500 times was also better with control effects of 84.59% on branches, 88.75%, 90.37% and 89.63% on fruits at harvesting time, 15 days and 30 days during storage respectively. These tests provided a sound basis for fungicide registration and for chosing suitable fungicides to control Physalospora piricola in apple production.