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Enhancement of the sterile male performance in Bactrocera philippinensis through access to protein (yeast hydrolysate) and/or exposure to methyl eugenol (ME) was investigated in this study. The temporal occurrence of sexual maturity of B. philippinensis was determined for both laboratory sterile and wild flies. Laboratory tests were also conducted to determine the peak age of ME feeding in relation to male fly age and sexual maturity and effect of protein on the longevity of sterile males. Field cage mating tests were performed to examine the effect of adult diet (P+ vs. P−) and ME exposure (ME+ vs. ME−) on the mating competitiveness of the sterile male B. philippinensis. P+ME+ sterile male flies achieved significantly more matings with wild females than P+ME− or PE−ME− sterile males. Based on the relative sterile index, P+ sterile male flies were significantly more sexually competitive when competing for wild females than P− flies. The results confirm that the pre‐release diet can be significantly improved to increase the effectiveness of the application of the sterile technique against B. philippinensis.

The mango pulp weevil, Sternochetus frigidus (F.), is an important quarantine pest preventing the export of mangoes from the Philippines to the United States and other countries. Previously, a radiation dose of 100 Gy was proposed for phytosanitary treatment of S. frigidus based on dose-response studies with larvae, pupae, and adult weevils. To validate an irradiation treatment, large-scale confirmatory tests were conducted with adults (the most radiation-tolerant stage) in mangoes at 100 and 150 Gy. After treatment, adults were removed from fruit, sexed, and mated in pairs to observe any reproduction. At 100 Gy, adults laid a small number of eggs but none of the eggs hatched. At 150 Gy (measured doses 96.7-164.1 Gy),4,559 treated weevils laid no eggs, indicating that this dose caused complete sterility. Irradiation treatment with a minimum absorbed dose of 165 Gy will therefore provide quarantine security for S. frigidus in exported Philippine mangoes.

The effect of irradiation on the fecundity, egg hatchability, and longevity of the coconut leaf beetle (CLB) – Brontispa longissima (Gestro) – was studied using different doses of gamma radiation ranging from 20–50 Gy for pupa and adult males, and 20–40 Gy for adult females. The fecundity and fertility of adults decreased with irradiation dose. The pupae were more sensitive to irradiation than the adults based on LD50 values after 14 d. Adult females were more sensitive to irradiation than males based on fecundity and egg hatchability. No eggs were hatched at 40 Gy in irradiated females (IF) mated with unirradiated males (UM) and at 50 Gy in unirradiated females (UF) mated with irradiated males (IM), albeit with a significant effect on longevity at this dose. Using 45 Gy for mating competitiveness studies at a ratio of 1:15:1 (UF: IM: UM), wild females’ acceptance of IM was high based on the relative sterility index (RSI) value of 0.66.

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