Effect of hot water treatment for controlling anthracnose of mango fruits of Tainung No.1 variety.
Yang H. R., Lin Y. T.
Author Affiliation: Chiayi Agricultural Experiment Station, Taiwan Agriculture Research Institute, Chiayi, Taiwan.
Plant Protection Bulletin (Taipei) 39 : 241-249
Abstract : Appressoria of C. gloeosporioides [Glomerella cingulata], the cause of mango anthracnose, formed on cellophane, were dipped into hot water at different temperatures for 5 minutes. The ability of fungal regrowth on acidified PDA was completely inhibited by hot water treatment above 49°C. Mango Tainung No.1 variety fruits were dipped into 53° hot water for 5 minutes, removed, immediately dripped with tap water to reduce the temperature and ripened for 1 day. The treated fruits were kept at 28° and RH 85% in a growth chamber and monitored for anthracnose. The percentage of treated fruits 4 days after hot water treatment with 3 lesions was 90, 100 and 96.7%, respectively, and 34.5, 5 and 43.3% in untreated fruits, in 3 trials, respectively. These values were reduced to 53.3, 85 and 63.3% for treated fruits, and 0% for all untreated fruits 7 days after treatment in the 3 trials, respectively. The percentage of healthy fruits 4 days after treatment was 56.7, 85 and 86.7% in treated fruits and 24.1, 0 and 23.3% of untreated fruits in 3 trials, respectively. After 7 days of ripening, these values were reduced to 40, 25 and 6.7% for the treated fruits and 0% for all the untreated fruits. The average number of lesions/fruit was 23.4, 26.7 and 15.2 for untreated fruits and 2.7, 2.2 and 5.3 for the treated fruits 7 days after treatment in the 3 trials, respectively. There was no heat damage to the fruits after the 53°/5 minutes hot water treatment. The average Brix values of treated and untreated fruits, 12 days after ripening, were 25.3 and 22.2, respectively.