Enhancement of efficacy in controlling postharvest decays and extending shelf life of mangoes by combined pre- and postharvest chemical applications.
Huang SiLiang, Zhu GuiNing, Qin LiPing, Zhou XiangYang, Huang FuXin, Li QuanFu, Yan WeiHong, Huang HuiNian, Cen ZhenLu, Fu Gang, Hu ChunJin
Author Affiliation: College of Life Science and Technology, Nanyang Normal University, Nanyang 473061, China.
International Journal of Agriculture and Biology 14 : 176-182
Abstract : To maximize the control of postharvest diseases and extent the shelf life of mangoes, pre-harvest chemical applications in combination with postharvest ones were performed in 2007 in Tianyang County, Guangxi, China. In a small-plot field trial, three fungicide combinations of azoxystrobin (125-250 mg L-1) plus mancozeb (100 mg L-1) were periodically sprayed on two 10-years-old mango cultivars from initial blooming until harvest. CaCl2 was added to the fungicide mixtures at a concentration of 0.6% (w/v) from fruit set and development. Spray interval from panicle emergence to fruit set was 10 days, while from fruit set to maturity was 15 days. At commercial maturity, mangoes were harvested and drenched in a prochloraz (450 mg L-1) solution for 10 min and packaged in a carton box with ethylene absorbent bags. After 23 or 25 days of storage (29±3°C & 70-85% RH), the percentage of sound fruit and decay-controlled efficacy on two cultivars with both pre- and postharvest chemical applications were significantly higher than those fruit only with pre- or post-harvest treatments. FC-3 (125 mg L-1 azoxystrobin plus 1000 mg L-1 mancozeb) was the best pre-harvest fungicide combination, in which the azoxystrobin was at a lower concentration than the other combinations. In a separate demonstration field trial, in which the fungicide combination (167 mg L-1 azoxystrobin plus 1000 mg L-1 mancozeb) was applied before harvest, the enhanced efficacies in controlling postharvest decays and extending shelf life of mangoes by combining the pre-harvest chemical applications with the postharvest ones were also confirmed. Three types of diseases (anthracnose, stem end rot & aspergillus rot) were mainly responsible for the rotted mangoes during storage. Colletotrichum gloeosporioides was identified as the causal agent of the anthracnose. The three pathogens (Botryodiplodia theobromae, Dothiorella dominicana & Phomopsis mangiferae) were associated with the stem end rot, while the other three (Aspergillus oryza var oryzae, A. niger & A. japonicas var. aculeatus) with the aspergillus rot.