SELECTIVE ATTRACTION OF Vespula germánica (Hymenoptera: Vespidae) TO FEEDING BAITS ENHANCED WITH ISOBUTANOL AND ACETIC ACID

Abstract

Vespula germanica (F.) has a negative impact on agriculture, beekeeping, and tourism in Chile. Therefore, environmentally-friendly strategies need to be implemented to control this serious pest. The objective of this study was to evaluate the response of adults of V. germanica to different types of baits with acetic acid + isobutanol (AAIB) added. The selected baits were: blood and bone flour (BF), raspberry jam (RJ), and sweet condensed milk (CM). The trial was conducted in a severely infested site in central Chile. Mixtures were placed in bottle traps. All of the traps were monitored daily from Monday to Friday during 5 weeks, and rebaited every week. A randomized complete block design, with 12 treatments and 4 replicates was used. Captures of V. germanica and other social hymenopterans were identified and data were recorded; V. germanica individuals approaching the trap openings (= visits) were also counted. A number of 15,480 V. germanica individuals, which were mostly workers, were captured. The most attractive baits were CM and BF + 2 mL AAIB. Feeding baits attracted significantly more workers with increasing concentrations of chemicals (AAIB), and significantly more wasps than the feeding baits alone. Lesser captures occurred of Apis mellifera workers (1,046), while the preference trend differed from that observed for V. germanica in several treatments. A number of 854 Polistes buyssoni workers were captured, but no differences were found between treatments. In addition, a number of 466 V. germanica visited the traps, but the trend observed with captures only occurred in traps baited with BF + AAIB, whereas no preference trend was observed for mixtures with RJ and CM. The results indicate that these attracting baits can be used not only to massively and selectively capture and destroy adults of V. germanica, but also to develop feeding baits not attractive for A. mellifera.

ATTRACTION OF Vespula germánica WORKERS TO PROTEIN BAITS MIXED WITH INSECTICIDES

“…This is a wild and semi-mountainous creek area, dominated by xeric schrub and sclerophyll trees (Gajardo, 1994). In this area, V. germanica presents large populations (Curkovic et al, 2017). Four sites spaced approx.…”

“…The selected attracting feeding bait was blood and bone flour (BBF), which is a by-product of the meat industry containing 20% protein, 22% Ca, and 11% P (Estay et al (2008). Al- and Curkovic et al (2017) have described meat as a highly efficient product in baits against V. germanica and V. orientalis (L.). The by-product above mentioned was chosen based on both attractiveness to V. germanica and selectivity to Apis mellifera L. (Curkovic et al, 2017).…”

“…Al- and Curkovic et al (2017) have described meat as a highly efficient product in baits against V. germanica and V. orientalis (L.). The by-product above mentioned was chosen based on both attractiveness to V. germanica and selectivity to Apis mellifera L. (Curkovic et al, 2017). Active ingredients (a.i.)…”

“…Therefore, mechanisms to control this wasp need to be developed and implemented. The use of animal protein as baits for traps has been studied on V. germanica (Estay et al, 2008;Curkovic et al, 2017). Efficient attractants need to be selective (Curkovic et al, 2017) and powerful in order to attract large numbers of workers (Day and Jeanne 2001).…”

“…The use of animal protein as baits for traps has been studied on V. germanica (Estay et al, 2008;Curkovic et al, 2017). Efficient attractants need to be selective (Curkovic et al, 2017) and powerful in order to attract large numbers of workers (Day and Jeanne 2001). Besides, it is possible to prepare toxic baits (mixed with insecticides) to either destroy adults (workers, queens, males) visiting a trap, or affect the colony when they return inside the nest (Estay et al, 2008).…”