Impact of Defoliation Timing on Peanuts.

Crop yields are adversely impacted by canopy defoliation. Canopy defoliation in peanuts may occur from a multitude of factors; however, this study was intended to simulate defoliation from foliage-feeding caterpillars. The research was conducted to determine the severity of yield loss resulting from complete defoliation applications throughout the growing season. Insect infestations are random, variable in size, and not well understood; therefore knowing how peanuts respond to canopy defoliation percentage may be more informative than trying to understand and manage crops based off feeding patterns or insect infestation levels. Newer peanut cultivars lack current information in regards to integrated pest management, especially in Mississippi where peanut production is relatively new when compared to other crops such as corn, cotton, rice, or soybeans. Knowing how current peanut cultivars respond to defoliation at different times throughout the season will help extension personnel make informed insect management decisions and will allow growers to become more efficient users of pesticides. This study was designed to determine the most detrimental canopy defoliation timings in peanut. Research took place at the Delta Research and Extension Center in Stoneville, Mississippi in 2014 to evaluate the yield response of peanuts completely defoliated at seven different timings (35, 50, 65, 80, 95, 110 days after planting). In 2014, all defoliation treatments other than 110 days after planting resulted in reduced yields when compared to the non-treated. Pod yield was most severely impacted when peanut canopies were defoliated at 50 and 80 days after planting, resulting in yields of 19.65% and 27.99% below the untreated, respectively. Identifying these specific times in which defoliation had a greater negative physiological response will lead to a more focused management regime in the future.