Vol. 12, Special Issue 12 (2023)

Author(s):
Prashant Mangalgikar, Karumuru Raja Madhura Bhanu, Vasuki Belavadi, Chandrashekharaiah Muniyappa and Byrappa Ammagarahalli

Abstract:
Coffee white stem borer, Xylotrechus quadripes primarily targets Coffea arabica while showing less preference in Coffea robusta. C. arabica bark might contain volatiles that attract female beetles for egg deposition. Our study aimed to identify these plant volatiles and assess their efficacy when used in conjunction with pheromones to enhance the performance of sex pheromone traps in the field. In the electroantennography (EAG) investigation, we employed virgin females, mated females, and males of the CWSB to evaluate eight chemicals that had exhibited heightened responses in preliminary assessments. Notably, when presented with (E)-2-Hexenal and (E)-2-Hexenal:(S)-2-hydroxy-3-decanone (1:1 ratio), males and virgin females displayed significantly stronger responses, while mated females did not exhibit a significant response. Experiments conducted in wind tunnels corroborated the findings from the EAG analysis. In comparison to males and mated females, virgin females displayed a more favorable response to these eight treatments. However, in the wind tunnel experiments, the response to (E)-2-Hexenal: (S)-2-hydroxy-3-decanone (1:1) was higher in virgin females, mated females, and males. Subsequently, the field trail results aligned with the outcomes of the EAG and wind tunnel experiments. Most of the test compounds yielded comparable results, suggesting that X. quadripes may employ a variety of substances within its habitat and host community. These findings shed light on the complex chemical ecology of the coffee white stem borer and offer insights into potential pest management strategies.