Improving the Monitoring of the Walnut Husk Fly (Diptera: Tephritidae) Using Male-Produced Lactones

Abstract

It is important to monitor fruit flies (Diptera: Tephritidae) efficiently to implement sustainable means of control. Attractants are often used to increase the efficiency of sticky traps deployed in orchards to monitor Lepidopterans, but remains to be developed to monitor fruit flies. Rhagoletis completa Cresson (Diptera: Tephritidae) is an invasive species in the walnut orchards of Europe, and is commonly monitored with yellow sticky traps. In this study, we collected the volatile compounds released by male and female R. completa, and identified two lactones released exclusively by males. We then formulated both lactones in long-lasting volatile dispensers, and we quantified their release rate over a 26-d period. Finally, during the entire period when female flies are present in the field, we compared the efficiency of the conventional monitoring method using unbaited yellow sticky traps with yellow sticky traps associated with a dispenser releasing both male-produced lactones. These assays were conducted in 54 walnut orchards in France, in 2017. The number of fruit flies caught with sticky traps associated with lactones dispensers was increased by up to 10 times each week. Lactone-baited traps also allowed earlier detection in the season. These field results are promising for R. completa monitoring. A complete chiral identification of these lactones should be performed along with a clarification of their role in the sexual communication of R. completa.

Chemical Compounds from Female and Male Rectal Pheromone Glands of the Guava Fruit Fly, Bactrocera correcta

“…However, ME only attracts male flies [10,11], thus limiting the possibility of monitoring the entire fly population or trapping females. To develop new strategies for the detection, monitoring, and trapping of this pest, pheromones that are safer and better attractants need to be developed [12]. It is well known that pheromone components of several Bactrocera species, usually released by males, can be isolated and identified by extracting the rectal glands [13,14,15,16,17].…”

The Effect of Winter Length on Duration of Dormancy and Survival of Rhagoletis completa (Diptera: Tephritidae) and Associated Parasitoids From Northeastern Mexico

“…Economic losses are the result of nut staining, increased percentage of adhering hull, and % shrivel, and reductions in edible yield and relative value (Coates 2005, Solar et al 2019). Synthetic pesticide use restrictions have fostered the development of environmentally sound management tactics (Sarles et al 2015, 2017, 2018) which could include biological control. The only major walnut producing area that has not been invaded by the walnut husk fly is China.…”

Male-Produced (−)-δ-Heptalactone, Pheromone of Fruit Fly Rhagoletis batava (Diptera: Tephritidae), a Sea Buckthorn Berries Pest

“…In the majority of Tephritidae species, mating is mediated by a combination of chemical, acoustic and visual cues. Pheromones play a key role during the mate-searching phase and, in general, they are produced by males to attract females [15,23]. The results of our experiments showed that R. batava antennae from both sexes react to a single compound, δ-heptalactone, detected exclusively in the headspace emissions from males.…”

“…The pheromone mediating attraction of Rhagoletis flies has been identified for walnut husk fly, Rhagoletis completa Cresson (Diptera: Tephritidae). Two lactones, namely δ-hexalactone and δ-heptalactone at the ratio 4:6, were released exclusively by males and showed significant attractiveness under field experiments [15]. Unfortunately, the sex of the specimens caught in the traps was not determined; hence, information is insufficient to determine whether one or both sexes responded to the lactones.…”