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48th TWC, Tob. Work. Conf., 2018, abstr. 56

Assessing non-chemical strategies to increase an important predator in flue-cured tobacco

NELSON P.; BURRACK H.; SORENSON C.
North Carolina State University, Raleigh NC USA

The spined stilt bug, Jalysus wickhami (Say), is the most abundant predator in flue-cured tobacco, feeding on aphids and caterpillar eggs. Stilt bugs are voracious predators of tobacco budworms and hornworms; a single stilt bug has the potential to prevent the development of over 2000 budworm larvae throughout its 80-day life. Stilt bug densities in tobacco can be as high as ten insects per plant, providing a potentially massive amount of natural pest control; however, pest management practices such as insecticide use have been linked to significantly lower numbers of stilt bugs. Stilt bugs have a close relationship with tobacco plants, taking drinks essential to their survival from the plant’s vascular system. This behavior does not damage the plant and is compatible with systemic applications of Admire Pro; the insecticide doesn’t reduce stilt bug numbers. Stilt bugs also feed on dead insects trapped in glandular trichomes on the surface of tobacco plants, a recently appreciated form of plant provided food. In natural systems, research has demonstrated that sticky wild flowers similarly trap insects with glandular trichomes, increasing predatory arthropod abundance and reducing damage to plants by herbivores. Providing predators with alternative food is one method for increasing their abundance. The goal of this research was to assess the potential of manipulating plant-provided food to increase stilt bug predatory activity. In 2016 and 2017, we manipulated the amount of dead insects on tobacco plants by adding dead fruit flies to plants. Counts of caterpillar pests and predators were taken weekly and green leaf weight was measured near harvest. Plants augmented with dead insects hosted greater numbers of stilt bugs, however the impact on caterpillar pests and their damage was variable. This research is the first step in assessing the efficacy of augmenting tobacco predators with alternative food sources. (Reprinted with permission)