Location: Fruit and Tree Nut ResearchTitle: In-shell Fumigation to Control Larval Pecan Weevil
|AIKINS, MICHAEL - Kansas State University|
|THOMS, ELLEN - Emt Consulting, Llc|
|PHILLIPS, THOMAS - Kansas State University|
Submitted to: Pecan Grower
Publication Type: Trade Journal
Publication Acceptance Date: 9/24/2020
Publication Date: 1/10/2020
Citation: Cottrell, T.E., Aikins, M.J., Thoms, E., Phillips, T.W. 2020. In-shell Fumigation to Control Larval Pecan Weevil. Pecan Grower. 32: 66-72.
Interpretive Summary: We evaluated the potential to use sulfuryl fluoride to control larval pecan weevil infesting pecan nuts. This research showed that fumigation of in-shell pecan nuts with sulfuryl fluoride will kill pecan weevil larvae within the nuts. We calculated that a lethal accumulated dosage (LAD99) of sulfuryl fluoride for pecan weevil was 1052.0 g-h/m3 with a 95% confidence interval of 683.21 to 2573.0 g-h/m3. We also conducted a confirmatory trial and 1300 g-h/m3 was selected as the sulfuryl fluoride dosage for a proposed quarantine treatment schedule. Fumigating pecans with sulfuryl fluoride can control larval pecan weevil infestations in nuts.
Technical Abstract: Sulfuryl fluoride was evaluated for control of larval pecan weevil infesting pecan nuts at 25oC for a 24 h exposure. A known number of infested nuts was acquired by artificially infesting pecan nuts. Infested nuts were fumigated with six concentration × time (CT) treatment dosages of sulfuryl fluoride (0 – 750 g-h/m3) within air-tight, glass containers. The sulfuryl fluoride concentration in each fumigation container was analyzed 30 min after sulfuryl fluoride introduction and just prior to termination of the experiment. Mean sulfuryl fluoride CT dosages were calculated from sulfuryl fluoride measurements and used to determine that the lethal accumulated dosage (LAD99) of sulfuryl fluoride for pecan weevil was 1052.0 g-h/m3 with a 95% confidence interval of 683.21 to 2573.0 g-h/m3. In a confirmatory trial, we used two sulfuryl fluoride CT dosage treatments, 1100 and 1300 g-h/m3, and a non-fumigated control. All larvae were dead in both fumigation treatments by 14 days post-fumigation. Due to higher mortality in the non-fumigated control in the confirmatory trial compared to that of the dose-response trial, 1300 g-h/m3 was selected as the sulfuryl fluoride CT dosage for a proposed quarantine treatment schedule. Fumigating pecans with sulfuryl fluoride can control larval pecan weevil infestations in nuts.