Efficacy and Phytotoxicity of Phosphine as Fumigants for Frankliniella occidentalis (Thysanoptera: Thripidae) on Asparagus
2018
Kyung, Yejin | Kim, Hyun Kyung | Lee, Jae Seon | Kim, Bong-Su | Yang, Jeong-Oh | Lee, Byung-Ho | Koo, Hyun-Na | Kim, Gil-Hah
The insecticidal activity of phosphine (PH₃) and ethyl formate (EF) toward Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae) and their phytotoxicity to asparagus were evaluated. Both the PH₃ and EF fumigants showed higher lethal concentration and time (LCT) values at lower temperatures. The LCT₉₉ values of PH₃ and EF at 5°C in a 12 liters desiccator for 4 h showed the following ranking: eggs (64.69 mg·h/liter for PH₃ and EF indicating phytotoxicity to asparagus), nymphs (5.54 and 17.48 mg·h/liter, respectively), and adults (3.83 and 14.67 mg·h/liter, respectively). The adsorption of PH₃ was approximately 11% at 2°C and 13% at 5°C, whereas the adsorption of EF increased sharply to 88% at 2°C and 97% at 5°C. The hatching rate of F. occidentalis eggs was approximately 95% at all locations (top, middle, and bottom) in the presence of 4 mg/liter PH₃ at 5°C in a 0.65-m³ fumigation chamber for 24 h. However, extension of the treatment to 48 h resulted in 100% inhibition of egg hatching. The atmospheric level of PH₃ decreased below the threshold limit value after 80 min, and phytotoxicity was not observed. The results revealed that EF is highly absorbed by asparagus and is not suitable as a fumigant, but PH₃ is a suitable alternative to the fumigant methyl bromide for the control of western flower thrips in asparagus.
显示更多 [+] 显示较少 [-]