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ARS Home » Southeast Area » Stoneville, Mississippi » Southern Insect Management Research » Research » Publications at this Location » Publication #405843
Research Project: Insect Control and Resistance Management in Corn, Cotton, Sorghum, Soybean, and Sweet Potato, and Alternative Approaches to Tarnished Plant Bug Control in the Southern United States

Location: Southern Insect Management Research

Title: Severe Defoliation of Vegetative Maize Plants Does Not Reduce Grain Yield: Further Implications with Action Threshold

Author
item BLANCO, CARLOS - University Of New Mexico
item CONOVER, KEVIN - University Of Maryland
item DIVELY, GALEN - University Of Maryland
item HERNANDEZ, GERARDO - Langebio Cinvestav
item Portilla, Maribel
item NAVA-CAMBEROS, URBANO - Juarez University Of The State Of Durango
item Abel, Craig
item WILLIAMS, PAUL - US Department Of Agriculture (USDA)
item HUTCHISON, WILLIAM - University Of Minnesota

Submitted to: Southwestern Entomologist
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/28/2023
Publication Date: 12/15/2023
Citation: Blanco, C., Conover, K., Dively, G., Hernandez, G., Portilla, M., Nava-Camberos, U., Abel, C.A., Williams, P., Hutchison, W. 2023. Severe Defoliation of Vegetative Maize Plants Does Not Reduce Grain Yield: Further Implications with Action Threshold. Southwestern Entomologist. https://doi.org/10.3958/059.048.0404.

Interpretive Summary: Maize (Zea mays L.), the most productive and planted cereal, is defoliated around the world by the fall armyworm (FAW) (Spodoptera frugiperda J. E. Smith). Close to 200 million hectares are currently threatened by this pest, and its prevalent control method is the application of synthetic insecticides and genetically engineered Z. mays that produces proteins of the bacterium Bacillus thuringiensis. The damage of FAW on maize foliage is very apparent, and the defoliation often implies a reduction on grain yield.

Technical Abstract: Maize defoliation has been perceived as a negative effect on grain yield. Biotic and abiotic factors reducing its leaf area have been studied yielding contrasting results. When maize is defoliated before developing its seventh leaf (V7), it has a great capacity to compensate the foliar loss without an impact on grain production. More than two thirds of 27 reviewed publications indicate that maize yield is not affected by severe defoliation when plants have not reached V7. Here we present results of seven maize lines with severe (75%) defoliation one, two, or three times before reaching V7, without reducing grain production as compared with intact plants. In fact, one early defoliation at V2 significantly produced more grain than the control. It is important to reconsider the unnecessary recommendations to apply insecticides against maize defoliators when maize plants have not developed their seventh leaf.