The effect of subfreezing temperatures on survival of Bemisia tabaci MEAM1

Authors: Turechek, William; Rennberger, Gabriel; Adkins, Scott; LUCAS, LEON - Glades Crop Care; PARKS, FELICIA - Glades Crop Care; MELLINGER, CHARLES - Glades Crop Care; SMITH, HUGH - University Of Florida

Submitted to: Crop Protection
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/19/2023
Publication Date: 4/29/2023
Citation: Turechek, W., Rennberger, G., Adkins, S.T., Lucas, L., Parks, F., Mellinger, C., Smith, H. 2023. The effect of subfreezing temperatures on survival of Bemisia tabaci MEAM1. Crop Protection. 170:106262. https://doi.org/10.1016/j.cropro.2023.106262.
DOI: https://doi.org/10.1016/j.cropro.2023.106262

Interpretive Summary: The sweet potato white fly Bemisia tabaci is a destructive pest on a wide variety of agricultural crops. White flies are managed largely through the use of insecticides, but B. tabaci has developed tolerance or resistance to a broad range of active ingredients. Identifying events where insecticide applications could be delayed or eliminated could contribute significantly to the mitigation of insecticide resistance. One such event is cold weather. In a designed experiment, it was shown that white fly mortality could be predicted through a simple model of temperature and exposure time. This model was applied retroactively to six seasons of field data collected in southwest Florida during the months of November through February. Significant drops in the white fly population were mostly associated with two or more severe cold events as identified by the model – separated by no more than 7 days. Moreover, the decrease was sustained for 4-6 weeks after the last event. The ability to predict decreases in the white fly population in response to freeze events gives growers the opportunity to relax insecticide schedules, particularly in the spring cropping season, with high confidence that their crop is at low risk to white fly damage.

Technical Abstract: The sweet potato white fly Bemisia tabaci is a destructive pest on a wide variety of agricultural crops. White flies are managed largely through the use of insecticides, but B. tabaci has developed tolerance or resistance to a broad range of active ingredients. Rotation of insecticide modes of action using the treatment interval approach is a strategy for reducing the development of insecticide resistance. Additionally, identifying events where insecticide applications could be delayed or eliminated could also contribute significantly to the mitigation of insecticide resistance. One such event is cold weather, which can decrease white fly activity including dispersal and mating, and when temperatures fall below freezing a substantial proportion of the white fly population can be killed. The objective of this research was to quantify the effects of exposure period to subfreezing temperatures on the mortality of adult white fly. Specifically, exposure to the range of temperatures between 2°C and -10°C for times between 2 h and 48 h. Results showed that white fly mortality could be predicted through a non-linear function of a composite variable of temperature and exposure time (x). This model was applied retroactively to six seasons of field data collected in southwest Florida during the months of November through February. Values of x were calculated for each cold event that occurred as a measure of its severity, and those values were compared to observed trends in the white fly population. Based on observation and model output, significant drops in the whitefly population were mostly associated with two or more cold events – separated by no more than 7 days – with at least one of those events with x > 13. Moreover, the decrease was sustained for 4-6 weeks after the last event. The ability to predict decreases in the whitefly population in response to freeze events gives growers the opportunity to relax insecticide schedules, particularly in the spring cropping season, with high confidence that their crop is at low risk to white fly damage.