The common asparagus beetle (Crioceris asparagi) poses a significant threat to asparagus production, particularly during the harvest season. Once laid, its eggs are difficult to remove and adults cause notable feeding damage on spears leading to economic losses for growers. Insecticides are commonly employed to manage asparagus beetle adults and eggs during harvest, aiming to prevent oviposition by killing the adults. Given the frequent harvesting of asparagus spears, insecticides with 1-day preharvest intervals are essential. My first chapter evaluated various contact synthetic and organic insecticides with 1-day preharvest intervals, testing their efficacy on asparagus spears in both field and laboratory settings. Acetamiprid and carbaryl proved effective in reducing adult and egg counts in field plots, while spinosad demonstrated comparable efficacy to carbaryl in laboratory bioassays. Pyrethrin effectively suppressed egg numbers but had no impact on adult populations. More importantly, in our bioassays we found that regardless of coverage lengths, insecticides reduced beetle numbers. Furthermore, both field and lab trials revealed efficacy was retained for lowering beetle mortality up to 48 hours. My second chapter investigated the host selection behaviors of the common asparagus beetle, revealing a preference for purple, tall, thin, and undamaged spears, with the presence of a spear tip being crucial for oviposition. Beetles mated more frequently on spears with intact tips and deposited significantly more eggs compared to those with their top parts removed. These findings provide valuable insights for developing sustainable control practices to manage the common asparagus beetle.
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