Improvement of bait sprays for the control of Bactrocera oleae (Diptera: Tephritidae)

Abstract

The control of the olive fruit fly Bactrocera oleae (Gmelin) is based on insecticides that are usually applied as bait sprays. Large-scale field experiments were conducted in the Kolymvari region of Crete (Greece) to evaluate the efficacy of several bait spray solutions against the fly that were applied at the recommended spraying volume per hectare (or 300 ml per treated tree), compared applications at volumes reduced by two and three fold (150 and 100 ml, respectively). The trophical attractant (hydrolysed protein at 75% w/w) that was used was mixed with alpha-cypermethrin, thiacloprid, thiacloprid + deltamethrin or dimethoate, and these formulations were tested during three successive summers (2012–2014) according to European Plant Protection Organisation (EPPO) standards. The products were alternated with one another over time in the experimental plots. The results indicated that all of the bait spraying solutions of the tested products were effective against B. oleae at all of the doses tested and resulted in significantly lower olive fly populations compared with the standard recommended dose, which was indicated by the fly catches in the nets of McPhail traps within the experimental plots. The percentages of live infestations of B. oleae were very low (<2%, except in 2013 due to a very low olive fruit yield), as was the number of applications each year, which was 6–7 and did not differ among treatments. The benefits of this concept in the management of the pest and potential future improvements of the method are discussed.