Use of insect row cover and reflective silver plastic mulching to manage whitefly for zucchini production

Authors: RUTZ, THIAGO - University Of Georgia; COOLONG, TIMOTHY - University Of Georgia; SRINIVASAN, RAJAGOPALBABU - University Of Georgia; SPARKS, ALTON - University Of Georgia; DUTTA, BHABESH - University Of Georgia; CODOD, CLARENCE - University Of Georgia; Simmons, Alvin; DA SILVA, ANDRE - Auburn University

Submitted to: Insects
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/7/2023
Publication Date: 11/9/2023
Citation: Rutz, T., Coolong, T., Srinivasan, R., Sparks, A., Dutta, B., Codod, C., Simmons, A.M., Da Silva, A.L. 2023. Use of insect row cover and reflective silver plastic mulching to manage whitefly for zucchini production. Insects. 14(11):863. https://doi.org/10.3390/insects14110863.
DOI: https://doi.org/10.3390/insects14110863

Interpretive Summary: The sweetpotato whitefly is a serious pest of many crops including vegetable crops, and it has recently become especially problematic in the southeastern United States. Growers rely on intensive insecticide spray programs to suppress extremely high populations during the fall vegetable growing season. A study was conducted to evaluate the benefit of using a reflective plastic mulch and an insect row cover as alternative methods to manage whiteflies in zucchini squash production in the field. The insect row covers reduced whitefly populations to zero until the covers were removed, and zucchini plants grown under the insect row covers and reflective silver plastic mulching had increased biomass accumulation due to the low insect counts in those treatments. The silver plastic mulch and row covers reduced the whitefly population (up to 87% in Georgia and up to 33% in Alabama), and increased both plant weight and total yield. The findings from this study can be used by growers and agricultural practicners for integrating the management of whiteflies in vegetable crops, and this may help researchers develop this strategy for the management of other pests.

Technical Abstract: The challenge created by the sweetpotato whitefly (Bemisia tabaci) for vegetable production has increased in the southeastern US. Growers have been required to use intensive insecticide spray programs to suppress extremely high populations during the fall growing season. The objective of this study was to evaluate the use of a reflective plastic mulch and an insect row cover as alternative methods to the current grower practices to manage whiteflies for zucchini (Cucurbita pepo) production. Field experiments were installed in a two-level factorial experimental design of row cover and plastic mulch treatments arranged in a randomized complete block design with four replications in Georgia 2020 and 2021, and Alabama 2021. Row cover treatments consisted of an insect row cover installed on zucchini beds at transplanting and removed at flowering and a no-cover treatment, while plastic mulch treatments consisted of a reflective silver plastic mulching and a white plastic mulching. Warm and dry weather conditions early in the growing season resulted in increased whitefly populations, regardless of location and year. In general, the reflective silver plastic mulching reduced whitefly populations compared to the conventional white plastic by 87% in Georgia in 2020, 33% in Georgia in 2021, and 30% in Alabama in 2021. The insect row cover treatment reduced whitefly populations to zero until its removal. Consequently, zucchini plants grown with the insect row cover and reflective silver plastic mulching had an increased rate of biomass accumulation due to the lower insect pressure in all locations. Zucchini grown using silver reflective plastic mulch and row covers had an overall increase of 17% and 14% in total yield compared to white plastic mulch and no-cover treatments, respectively. Significant differences in yield among locations were likely due to severe whitefly pressure early in the fall season, and total yields in Georgia in 2020 (11,451 kg ha-1) were 25% lower than in Georgia in 2021 (15,177 kg ha-1) and Alabama in 2021 (15,248 kg ha-1). In conclusion, silver plastic mulching and row covers reduced the whitefly population and increased biomass accumulation and total yield. These treatments can be considered a ready-to-use integrated pest management practice for growers.