Trapping system comparisons for and factors affecting populations of Drosophila suzukii and Zaprionus indianus in winter‐grown strawberry

• Published in: Pest management science Vol. 74; no. 9; pp. 2076 - 2088
• Main Authors: Renkema, Justin M, Iglesias, Lindsy E, Bonneau, Phanie, Liburd, Oscar E
• Format: Journal Article
• Language: English
• Published: Chichester, UK John Wiley & Sons, Ltd 01.09.2018; Wiley Subscription Services, Inc
• Subjects: African fig fly; alternative hosts; Attractants; Berries; Coloration; Crops; Drosophila suzukii; Eggs; Females; Flies; Fruits; Infestation; Insects; Limiting factors; monitoring; Morphology; morphotype; Organic chemistry; Pests; Population growth; Sambucus; spotted‐wing drosophila; Strawberries; Trapping; Winter; Zaprionus indianus; Florida; spotted-wing drosophila; alternative hosts; morphotype; African fig fly; monitoring; attractants
• ISSN: 1526-498X; 1526-4998
• DOI: 10.1002/ps.4904

BACKGROUND Drosophila suzukii (Matsumura) is a major fruit pest in temperate regions worldwide, but in subtropical Florida, winter‐grown strawberries have not been severely affected. Zaprionus indianus Gupta is another invasive drosophilid species and a pest of some tropical fruits. To improve monitoring, trapping systems for D. suzukii and Z. indianus were tested. Morphology, ovarian status and the suitability and availability of non‐crop hosts as possible D. suzukii population‐limiting factors were assessed. RESULTS Traps with commercial attractants captured more D. suzukii but fewer Z. indianus than those with a homemade mixture. In central and northern Florida, < 10% and 30‐80% of D. suzukii, respectively, exhibited darker, winter morph coloration, and 55‐75% of females from central Florida were carrying mature and/or immature eggs. Adult D. suzukii were reared from fruits of two of 28 potential hosts: elderberry (Sambucus nigra) and nightshade (Solanum americanum). Nightshade, but not elderberry, was common on field perimeters (21 and six of 36 fields, respectively). Traps placed in wooded or partially wooded field edges yielded the most D. suzukii. CONCLUSION Florida strawberry is at risk of D. suzukii infestation, as flies were captured throughout the growing season. However, fly captures remained relatively low, peaking at 1.5 flies per trap per day. In central Florida, the low availability and suitability of non‐crop hosts likely limit population growth. The finding of few flies in northern Florida may additionally be attributable to a greater proportion of flies displaying winter morph coloration than in central Florida. © 2018 Society of Chemical Industry Low levels of invasive drosophilids were found in Florida winter strawberries. There were just two suitable non‐crop host plants on field edges. Winter morphs were primarily found in cooler, northern fields.