Flea beetles (FB), (Coleoptera: Chrysomelidae), are common pests of cabbage and eggplant, but little is known about the FB populations in Virginia, their impact on yield, or the most effective control methods. This research investigates the FB populations and impact of their feeding injury on cabbage and eggplant in Southwest Virginia, and determines the most efficacious control methods. In Whitethorne, VA, cabbage and eggplant crops were vacuum sampled weekly throughout two summers. Crucifer flea beetle, Phyllotreta cruciferae (Goeze), and striped flea beetle, Phyllotreta striolata Fabr. were found on cabbage; whereas, eggplant flea beetle, Epitrix fucula (Crotch), and the tobacco flea beetle, Epitrix hirtipennis (Melsheimer) were found on eggplant. To evaluate the impact of FB feeding on these plants, insecticides were used to create a range of pest pressure. Flea beetle densities and defoliation was visually assessed weekly and individual plant as well as whole plot yields assessed at harvest. In both crops, as little as 20% defoliation significantly reduced yield, with higher defoliation resulting in lower yield. The efficacy of various insecticides was also evaluated; soil application of the systemic neonicotinoid dinotefuran had the fewest beetles, the least amount of leaf defoliation, and the highest yield in cabbage and eggplant. Lastly, deltamethrin-incorporated mesh row covers were evaluated and shown to provide excellent control of FB compared to an untreated row cover or a control; and comparable to the standard insecticide, dinotefuran. This research helps vegetable growers to better understand the severity of these pests and how to effectively combat them. / MSLFS

<p dir="ltr">The striped cucumber beetle (<i>Acalymma vittatum</i>) is a leading pest across a variety of cucurbit crops in eastern North America. These beetles can rapidly infest and damage a field, leading to frequent insecticide applications to manage them. Chemical control is effective at reducing beetle populations, but it also causes detrimental non-target effects on pollinators, which are essential for cucurbit yield. Developing a holistic IPM (integrated pest management) approach is necessary to manage pests while avoiding non-target effects in cucurbit production systems. </p><p dir="ltr">A unique and well-characterized behavior of striped cucumber beetles is their olfactory attraction to both plant volatiles and their species-specific aggregation pheromone, vittatalactone. The interacting effects of combining these olfactory stimuli for cucumber beetle attraction have not previously been tested. I expected when presented with plant volatiles and pheromone together, the striped cucumber beetles will show synergistic attraction, resulting in enhanced attraction stronger than the sums of the separate effects. Along with targeting striped cucumber beetles, I expected to elicit cross-attraction of related cucurbit pests (e.g., spotted cucumber beetle) to these same signals based on previous findings indicating cross-attraction. The expected cross attraction may be due to the reliance on olfactory cues to inform the related insects on preferrable host plants and nutrition. </p><p dir="ltr">Cucurbit systems are also highly reliant on pollination services for high-quality fruit; thus, the feasibility of these semiochemical tools depends on their influence on pollinator behavior. I expect pollinators to be attracted to floral volatiles but not vittatalactone or individual plant volatiles without the full complement of floral scent (e.g., indole, leaf volatiles). Altogether, this research aims to develop a targeted management tool for striped cucumber beetles and other cucurbit pests, while avoiding pollinator distraction or other detrimental effects.</p><p dir="ltr">To measure the efficacy of using olfactory signals as attractants, clear sticky cards were deployed in the field with combinations of pheromone paired with volatiles (floral and/or leaf), as well as the individual components, to quantify pest responses. Simultaneously, a pan trap sampling method was implemented to measure pollinator responses to the same semiochemical combinations. The results of the study demonstrate that striped cucumber beetles are strongly attracted to volatile lures containing pheromones, floral volatiles, and combinations of the two, although the combined pheromone and floral volatile treatments did not synergize beetle attraction. </p><p dir="ltr">Though combined lures did not synergize attraction, this data demonstrates additive effects on beetle behavior. The findings also highlight the importance of understanding seasonal disparities between the behavior of early and late generations of striped cucumber beetles. Temporal variation in attraction demonstrated by the pests is crucial to understand when to implement lure-based management strategies. Two years of testing floral volatile and herbivory-induced plant volatile (HIPV) lure treatments on key cucurbit pollinators showed varying levels of attraction. There was no attraction of focal cucurbit bees to the striped cucumber beetle pheromone, but there were differences in the response of pollinators to plant volatile components. </p><p dir="ltr">Cucurbits require high pollination activity for successful fruit, though the most important bees in pollinating this system are bees belonging to the genera, <i>Apis</i> and <i>Eucera</i>. Along with these bee groups, other bees such as those belonging to <i>Melissodes</i>, <i>Lasioglossum</i>, and <i>Bombus</i> are also known important pollinators. <i>Lasioglossum</i> bees showed a strong attraction to the full-floral blend, TIC (1,2,4-trimethoxybenzene, indole, (E)-cinnamaldehyde), but no preference for indole or HIPVs. <i>Melissodes</i> bees were most attracted to methyl salicylate and TIC, whereas <i>Eucera</i> bees exhibited strong attraction to ocimene and TIC. These findings suggest that different pollinator taxa have unique preferences for plant volatiles, highlighting the importance of optimizing lure combinations to avoid disrupting pollination activities in cucurbit production.</p><p dir="ltr">Additionally, this study revealed that other key cucurbit pests, such as spotted cucumber beetles and western corn rootworms, also showed strong attraction to the tested volatile components. These findings suggest that the selected volatiles may have broader implications for pest management beyond striped cucumber beetles. Further research is needed to fully understand the efficacy and refine formulations of these volatile lures to implement in IPM.</p>