Dispersal behavior of Euwallacea nr. fornicatus (Coleoptera: Curculionidae: Scolytinae) in avocado groves and estimation of lure sampling range

Authors: OWENS, DAVID - Orise Fellow; SEO, MEEJA - University Of Florida; Montgomery, Wayne; RIVERA-MAMOUNIS, MONIQUE - University Of Florida; STELINSKI, LUKASZ - University Of Florida; Kendra, Paul

Submitted to: Agricultural and Forest Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/28/2018
Publication Date: 4/3/2019
Citation: Owens, D., Seo, M., Montgomery, W.S., Rivera-Mamounis, M.J., Stelinski, L.L., Kendra, P.E. 2019. Dispersal behavior of Euwallacea nr. fornicatus (Coleoptera: Curculionidae: Scolytinae) in avocado groves and estimation of lure sampling range. Agricultural and Forest Entomology. 21(2):199-208.

Interpretive Summary: Invasive ambrosia beetles in the Euwallacea nr. fornicatus complex transmit a fungal pathogen that causes Fusarium dieback disease in susceptible hosts, which include avocado and native trees in Florida and California. Currently, these pests are detected with quercivorol lures, but recent ARS research identified a-copaene as a new attractant. In this study, scientists from the ARS Subtropical Horticulture Research Station (Miami, FL) and the University of Florida (Lake Alfred) investigated dispersal behavior of female E. nr. fornicatus through mark-release-recapture experiments in avocado groves and in laboratory flight mill tests. In addition, they estimated the effective sampling range of quercivorol and copaene lures, deployed alone and in tandem. In field tests, the 2-component lure captured significantly more beetles than single lures, and wind speed and direction had a strong influence on the number of females that dispersed, as well as the direction and distance of their flight. Sampling range was comparable among lure treatments, with 80% of marked beetles captured within 30-40 m of the release point. Laboratory tests indicated that these beetles have great flight capacity; average flight distance was 81 m in 24 hr, with a maximum distance recorded at 400 m. These results indicate that the combination lure provides the best detection of E. nr. fornicatus in Florida, with a recommended trap spacing of ~30 m. This information will help action agencies design effective surveillance programs for pest ambrosia beetles in avocado groves.

Technical Abstract: 1. Invasive ambrosia beetles in the Euwallacea nr. fornicatus species complex (Coleoptera: Curculionidae: Scolytinae) threaten avocado production in multiple countries. These pests are currently monitored with lures containing quercivorol, but a-copaene was recently discovered to be an effective attractant. 2. We investigated dispersal behavior of female E. nr. fornicatus in two Florida avocado groves using mark-release-recapture experiments and laboratory flight mills. Additionally, we estimated the sampling range of quercivorol and a-copaene lures deployed alone and in tandem. 3. The two-component lure recaptured 31.2% of marked beetles, significantly more than quercivorol (11.2%) or a-copaene (8.8%). Contour analysis indicated that wind speed and direction can influence the number of females that disperse, as well as the direction and distance of their flight. 4. Two methods were used to estimate sampling range, and both indicated comparable effective ranges for the three lure treatments, with 80% of marked beetles recaptured within 30-35 m of the release point. Average total flight distance in laboratory tests was 81.0 m in 24 h, with a maximum distance recorded at 400 m. 5. These results support that a combination of quercivorol and a-copaene lures provides the best detection of pest E. nr. fornicatus in Florida, with a recommended trap spacing of ~30 m in surveillance programs for this pest in avocado groves.