Submitted to: Journal of Agriculture of the University of Puerto Rico
Publication Type: Peer reviewed journal
Publication Acceptance Date: 8/8/2008
Publication Date: 10/30/2008
Citation: Jenkins, D.A., Diaz, E., Jenkins, D.M., Goenaga, R.J. 2008. Solar sterilization of abscised fruit: a cultural practice to reduce infestations of Anastrepha spp. around orchards. Journal of Agriculture of the University of Puerto Rico. 92(3-4):197-206. Interpretive Summary: Mangoes are widespread on the island of Puerto Rico and are a key source of fruit fly infestions, principally Anastrepha obliqua, in commercial orchards. If the population of fruit flies in naturalized and backyard mangoes could be reduced, commercial fruit growers would benefit by having to use less pesticide. This study found that mangoes exposed to the sun consistently attained internal temperatures around the temperature that has been found to be fatal for this insect (48°C) and that mangoes covered with a black plastic garbage bag consistently attained even higher temperatures (>55°C). Removing abscised mangoes from the shade and covering them with black plastic often resulted in higher mortality of larvae and may be an important tool in establishing a fruit fly-free-zone in Puerto Rico.
Technical Abstract: Abscised mangoes, Mangifera indica L., of several varieties were stored under varying conditions of insolation, including no sun (stored in a laboratory), shade (stored under the shade of a mango tree), full sun (stored in direct view of the sun), and covered in a black plastic bag and stored in direct view of the sun. The number of living Anastrepha obliqua (Marquart) larvae emerging from each treatment was compared and internal temperatures of the mangoes in the various storage regimes were recorded. Mangoes stored in the laboratory almost always produced more larvae than mangoes stored under the other regimes, even though internal temperatures of mangoes stored in the shade were not much higher than those of mangoes stored in the laboratory. Internal temperatures of mangoes stored stored under black plastic garbage bags in the full sun consistently reached reportedly fatal temperatures for A. obliqua and other Tephritidae. Nonetheless, mortality was not consistently higher in these treatments than in the treatments stored in the shade. We suspect that cloudy weather reduced the internal temperatures of the mangoes to sufficiently tolerable levels for larval survival. Removing abscised mangoes from the shade of the tree may reduce infestations on the arid side of the island where sunny days are more common. Our research suggests that removing abscised fruit from the shade of backyard trees, in concert with other cultural strategies, may be useful in establishing a fruit fly-free zone, or even island-wide eradication.