Evaluation of different bagging materials for the control of the fruit fly Anastrepha sp. (Diptera: Tephritidae) and fruit pathogens in Taiwanese guava fruits ( Psidium guajava L.).

摘要

The main problem in guava production is fruit fly damage; this insect feeds inside the fruit and facilitates the entrance of pathogens and fruit drop. This study evaluated different materials used for making protective bags for guava fruits in order to reduce fruit fly damage and pathogen presence, as well as to extend their life expectancy in the field. The study took place during the dry and rainy seasons in Carrillos, Alajuela, Costa Rica. During the first phase, four different bagging materials were evaluated: waxed paper, nylon fabric, Taiwan bag and telephone book paper, the latter normally used by local farmers; for the second phase, only Taiwan and nylon bags were used. Highly significant differences (F=66.75; p<0.0001) were found during the first bagging period in terms of percentage of protected fruit, where nylon > Taiwan > waxed paper > telephone guide paper. For the second period (F=38.13; p<0.0001) nylon bags protected more fruits than Taiwan bags. The longest duration of the bag in the field was obtained with nylon bags followed by telephone book paper, Taiwan and waxed paper bags. During the second phase Taiwan outlasted nylon bags. Telephone book paper and nylon yielded the highest amount of infected fruit during the first and second periods respectively. The highest number of fallen fruit was obtained in the control group during the first phase. During the dry season, the highest number of fruits affected by pathogens was found when the telephone book paper bags were used, while fruits bagged with nylon bags during the rainy season presented the highest number of fruits affected by pathogens. The results of this research show that the use of the nylon bag offered the highest protection against the fruit fly; however, it does not protect against pathogens which also affect guava production.