Effect of types of bagging materials on growth, quality and disease-insect damages in pummelo fruit in tropical humid conditions
Peel appearance and disease-insect damages are factors to determine the pummelo fruit grading apart from the size. To improve the peel appearance and reduce those damages and use less pesticides, different types of bagging materials with different light transparency and other characteristics were investigated for pummelo fruit bagging in tropical humid conditions in Thailand. It was found that the environmental conditions in bags were affected by the type of bag materials and resulted in fruit quality changes. Bagging reduced the light intensity but increased the temperature and relative humidity depending on the materials. Bagging was able to reduce the severity of fruit damages by plant pathogens, insects and fruit dropping. Moreover, the colour of the peel was more uniform and less blemish. However, the degree of positive or negative effects of fruit bagging strongly depended on the types of bag material and the bag covering techniques. The size of the fruit and the fruit quality measured as total soluble solids, titratable acidity and ascorbic acid were not significantly affected by the bagging or bagging materials. It was found that three types of bag were suitable for bagging. First, there is the white paper wax coated bag, which resulted in high percentages of fruits without or with slight peel blemish, a uniform colour of green-yellow peel, and a slight increase of the fruit weight. Secondly there is the synthetic fiber cloth bag, which also showed high percentages of fruits with no or a slight peel blemish, a uniform colour of the light green peel, but the price of this bag was higher compared with the first one. Third, there is the clear low cost plastic bag, the bagging gave reasonably higher percentages of fruits without or with a slight peel blemish compared with no bagging control, a less uniform colour of the green peel compared to the first and second bagging, and a slightly lower fruit weight. The suitable ages of fruit for bagging were between 2-3 months after full bloom. The important successful factors for bagging were the suitable techniques of bagging and the spraying of fungicide and insecticide before bagging.
Issarakraisila, M. (2018). Effect of types of bagging materials on growth, quality and disease-insect damages in pummelo fruit in tropical humid conditions. Acta Hortic. 1208, 319-324
pummelo, bagging, fruit quality