Sensitivity of Causal Pathogens of Mango Anthracnose to Several Fungicides and Control Effect of Systematic Application of Fungicides

Abstract

In order to establish a systematic fungicide application that is effective against mango anthracnose, we evaluated the sensitivity of the pathogen to the registered fungicides, the control efficacy of fungicide application during the fruit enlargement period, the presence or absence of phytotoxicity, as well as the control efficacy of the systematic application of a combination of different fungicides. We investigated the sensitivity of five types of registered fungicides against the conidial germination and mycelial growth of two pathogens, Colletotrichum gloeosporioides and C. acutatum. Mancozeb wettable powder, captan wettable powder, kresoxim-methyl dry flowable and azoxystrobin flowable were found to have high suppressive efficacy on both fungi. In contrast, sensitivity to iminoctadine albesilate acid chloride wettable powder differed between two pathogens, with conidial germination being suppressed in C. gloeosporioides, but not in C. acutatum. In 2008, we conducted a test to investigate the control efficacy of fungicide application during the fruit enlargement period. Kresoxim-methyl dry flowable and azoxystrobin flowable showed control efficacy and reduced the incidence of anthracnose by approximately 41% to 54%, compared to areas with no application, 5 days after harvest. In addition, neither fungicide caused phytotoxicity to the fruit. In contrast, the application of captan wettable powder showed no control efficacy and the fungicide solution caused flecks on the peel. In 2009 and 2010, we conducted a trial on the systematic application of a combination of four fungicides on two fields that were treated prior to apical bud formation (late December) up until the start of harvest (before bagging in late June). The results revealed that a high control efficacy of the treatment and the incidence of anthracnose was reduced by approximately 76% to 96%, compared to areas with no application, 5 days after harvest. In addition, the systematic application of fungicides caused no phytotoxicity to the fruit. Meta-analysis of the four tests conducted over 2 years showed that the incidence of anthracnose in areas with systematic fungicide application was significantly reduced to about 12% of that in the non-treated areas. These results show that our systematic application of fungicides is effective as a control measure against mango anthracnose.