Plant-derived compounds can be an environmentally friendly alternative to synthetic pesticide use for pest management. Essential oils (EOs) in several plant families have been found to be toxic to various pest species of insects through topical application, ingestion, and as fumigants. Previous studies revealed that, among various environmentally friendly insecticides, the EOs of Baccharis dracunculifolia and Pinus elliottii and an ethanol extract of Solanum granulosoleprosum plus Ricinus communis, were toxic to Ceratitis capitata and Anastrepha fraterculus (Diptera: Tephritidae) when applied topically to pupae or when ingested by adults. Here, we aimed to examine the potentially toxic effects of these plant-derived compounds when these two pestiferous fruit fly species were exposed to their vapors. We also examined their fumigant effect on female fecundity and fertility and compared it with water and ethanol controls. Exposure of C. capitata and A. fraterculus sexually mature adults to volatiles and vapors of both B. dracunculifolia and P. elliottii EOs resulted in lower longevity (half-life), survivorship, and female fecundity than the water vapor control. Toxicity of C. capitata was greater for P. elliottii than for B. dracunculifolia while the reverse was true for A. fraterculus. Exposure to vapors of S. granulosoleprosum + R. communis (S + R) had no effect on longevity but reduced survivorship of adults of both species. Interestingly, exposure to vapors of S + R, 50% (v/v) and pure ethanol resulted in greater fecundity of females of both frugivorous fly species than the water control. By contrast, fertility (% egg hatch) was in all cases high (>85%) and not different than the water control. Exposure to ethanol vapors appears to have similar effects on frugivorous tephritids as those reported on saprophagous and frugivorous species of Drosophila, a novel finding that may have important practical implications.

In the laboratory, adults of Prostephanus truncatus (Horn) preferred artificially or naturally (insect) damaged maize kernels to sound kernels when adults were tested individually or in groups. Survival of P. truncatus was similar when 1, 10, 40 or 80 adults were fed 100 g of shelled maize for 20 days; but more kernels were damaged at the highest adult density in comparison to the other densities of adults. Single P. truncatus adults on average damaged 9 maize kernels, but 10, 40, and 80 adults damaged approximately 15, 21 and 45 kernels, respectively, indicating that adults confined their feeding to only specific kernels. Survival of adults and number of kernels damaged were significantly affected when different quantities of shelled maize (25–500 g) were infested with 25 adults of P. truncatus. Adult surv at 25, 50, 100, and 200 g of maize/0.95–1 jar was similar (70.7–76.0%), but the number of kernels dama increased significantly from approximately 15 at 25 g to 61 at 200 g. These results suggested that shelled maize grain compaction, which is influenced by the quantity of grain, may affect survival of and damage by adults of P. truncatus. Adults of P. truncatus successfully infested 25 g of shelled maize and damaged about 15 kernels, indicating that adults could temporarily survive on such small quantities of grain spilled in and around storages before infesting stored-maize.