Investigating artificial diets as substrate for rearing pepper weevil, Anthonomus eugenii (Coleoptera: Curculionidae)

Abstract: The pepper weevil, Anthonomus eugenii, is one of the most economically damaging
pests of Capsicum sp. crops in North America and represents a concern as a globally invasive
species wherever pepper crops are cultivated. Given its resistance to many conventional
insecticides and cryptic biology, mitigating pressure imposed by this pest remains a persistent challenge. To address this, new management strategies and tools targeting pepper weevil are sorely needed, including assessment of biological control and the Sterile Insect Technique (SIT). An efficient mass-rearing system for pepper weevils is needed to support these initiatives. To address this need, we have explored several artificial diet additives and rearing protocols for their ability to maximize weevil production in this study. We first assessed the value of incorporating natural host plant material along with an artificial diet substrate to improve weevil egg laying. We showed that, by far, the most suitable egg-laying substrate consisted of fresh pepper leaf-covered artificial diet, compared to adding either dried or fresh forms of pepper plant material directly into the diet. We next examined ways to improve weevil egg-laying efficiency by comparing two different frequencies of fresh diet replacement. Overall, we showed that weevil egg laying could be just as good when diet was replaced every second day, which represents a considerable economy of time. Together, these results can be applied to develop efficient mass-rearing methods for pepper weevil, with positive implications for developing new management approaches targeting this pest.