ABSTRACT
The soursop Annona muricata is an important fruit for national market, and for exportation, but the crop is affected by pests and diseases. The seed borer wasp Bephratelloides cubensis Ashmead is the pest that produces the highest damage to the crop in Mexico. Sixty percent of damaged fruits and 5-50 seeds per fruit have been registered, with 25 percent reduction in yield. In Nayarit, Mexico, 100 percent of damaged fruits were recorded. In this State, an experiment with soursop was conducted to study the life cycle under field conditions and to determine diurnal behavior of the female of B. cubensis. The highest activity of the wasp was observed between 12:00h and 13:00h (35ºC, 54 percent RH and 409.34 luxes). Females oviposited in fruits with a diameter of 3.1-7.6 cm. Larvae of B. cubensis developed five instars, adults survived no longer than 22 days, and female survived longer than males; they lived 22 and 15 days, respectively. Life cycle of B. cubensis varied from 69 to 122 days.