Abstract
Three dose-response trials were performed in 2020 and 2021 to determine the tolerance of two Jack O’Lantern pumpkin cultivars to fomesafen applied preemergence at two Indiana locations: the Southwest Purdue Agricultural Center (SWPAC) and the Pinney Purdue Agricultural Center (PPAC). The experiment was a split-plot arrangement in which the main plot was the fomesafen rate of application (0, 280, 560, 840, and 1,220 g ai ha–1), and the subplot was the pumpkin cultivar (‘Bayhorse Gold’ and ‘Carbonado Gold’). As the fomesafen rate increased from 280 to 1,120 g ha–1, the predicted pumpkin emergence decreased from 85% to 25% of the nontreated control at SWPAC-2020, but only from 99% to 74% at both locations in 2021. The severe impact on emergence at SWPAC-2020 was attributed to rainfall. Visible injury included bleaching and chlorosis due to the herbicide splashing from the soil surface onto the leaves and included stunting, but injury was transient. As the fomesafen rate increased from 280 to 1,120 g ha–1, the predicted marketable orange pumpkin yield decreased from 95% to 24% of the nontreated control at SWPAC-2020 and 98% to 74% at PPAC-2021. Similarly, the predicted marketable orange pumpkin fruit number decreased from 94% to 21% at SWPAC-2020 and 98% to 74% at PPAC-2021. Fomesafen rate did not affect marketable orange pumpkin yield and fruit number at SWPAC-2021 and marketable orange pumpkin fruit weight at any location-year. Overall, the fomesafen rate of 280 g ha–1 was safe for use preemergence in the pumpkin cultivars ‘Bayhorse Gold’ and ‘Carbonado Gold’ within one day after planting, but there is a risk of increased crop injury with increasing rainfall.
Keywords
Dose-response; emergence; injury; protoporphyrinogen oxidase; yield
Date of this Version
8-2022
Comments
This is the publisher PDF of Arana J, Meyers SL, Johnson WG, Guan W (2022) Dose-response of two Jack O’Lantern pumpkin cultivars to fomesafen applied preemergence. Weed Technol. 36: 537–543. Published CC-BY, it is available at DOI: 10.1017/wet.2022.49.