Date of Graduation

12-2017

Document Type

Thesis

Degree Name

Master of Science in Entomology (MS)

Degree Level

Graduate

Department

Entomology

Advisor/Mentor

Johnson, Donn T.

Committee Member

Garcia, Maria E.

Second Committee Member

Lee, Jacquelyn A.

Third Committee Member

Steinkraus, Donald C.

Keywords

Alternative Hosts; Blackberry; Exclusion; Organic; Seasonal; Spotted Wing Drosophila

Abstract

Spotted wing drosophila (SWD), Drosophila suzukii (Matsumura) is a serious invasive pest of small fruit production in North and South America and Europe since 2008. The primary control method is to apply insecticides every 5-7 days. Therefore, it is necessary to develop control tactics that are less chemical dependent to enhance an integrated approach for SWD management. The objectives of this study were to monitor SWD populations in different crop systems and adjacent landscape habitats; identify wild hosts of SWD; evaluate the effectiveness of insect exclusion netting in tunnels to prevent blackberry and blueberry infestations, and compare effects of netted tunnels on temperature and fruit quality. The majority of seasonal averages of SWD were lower in the traps placed in fruit crop plots than in the perimeter traps located next to a refuse pile of culled fruit and mulch than the traps located in host crop species. Of the potential wild fruit hosts sampled in Arkansas, these 12 had SWD infested fruit: wild blackberry and dewberry (Rubus spp.), American pokeweed (Phytolacca americana L.), black cherry (Prunus serotina Ehrh.), Carolina buckthorn (Frangula caroliniana (Walter) A. Gray), porcelain berry (Ampelopsis glandulosa var. brevipedunculata (Maxim.) Momiy), amur honeysuckle (Lonicera maackii (Rupr.) Herder); autumn olive (Elaeagnus spp.); elderberry (Sambucus spp.); mulberry (Morus spp.); native honeysuckle (Lonicera spp.); and Carolina moonseed (Cocculus carolinus (L.) DC.). These SWD hosts ripened from early June into October. Tunnels with insect exclusion netting excluded SWD fly entry and prevented fruit infestations in 2016 and delayed SWD infestations in 2017. For 2016 and 2017, the seasonal total number of hours of SWD lethal temperatures inside the tunnel treatments (netted high tunnel = 69.4, 50.8, plastic low tunnel = 58.6, 68.0 and netted low tunnel = 54.6, 41.7) were slightly warmer than in the uncovered plot (53.4, 32.6). Low percentages of relative humidity (<65%) appeared to play an important role in the differences in fruit quality among the treatments. Netted low tunnel blackberries had significantly lower fruit firmness (6.9) than all other treatments (8.3, 7.7, 7.4). The uncovered plot had a significantly higher Brix (11.52) compared to the other treatments (9.31-9.68). It appears that the tunnels slightly lowered Brix levels with the recommended quality range being 10-12%. All netted blackberries in high (0.62) and low tunnels (1.11, 0.86) had significantly lower titratable acidity than the uncovered plot (1.49) indicating a slight reduction in fruit quality. There is potential for exclusion to be an effective control method against SWD, but additional studies should be conducted to explore modifications as well as the economics of building and implementation of exclusion netting into a management program. Understanding the seasonal phenology of alternative hosts and when SWD exploit them can help predict when and where populations may establish.

Download

Share

COinS