Submitted to: Peanut Research at Oklahoma State University
Publication Type: Experiment Station
Publication Acceptance Date: 9/30/2011
Publication Date: 12/10/2011
Citation: Godsey, C.B., Damicone, J.P., Taylor, R., Melouk, H.A. 2011. Evaluating variable rate fungicide applications for control of Sclerotinia. In: Partners and Progress - Peanut Research at OSU, 2011. Oklahoma Agricultural Experiment Station, P-1035. p. 11-13. Interpretive Summary:
Technical Abstract: Oklahoma peanut growers continue to try to increase yields and reduce input costs. Perhaps the largest input in a peanut crop is fungicide applications. This is especially true for areas in the state that have high disease pressure from Sclerotinia. On average, a single fungicide application costs $50-$60/acre to help control the disease. A large portion of the Oklahoma peanut crop is still grown in areas where Sclerotinia is present, so a solution to reduce fungicide input costs would greatly benefit producers struggling to control the disease. Precision agricultural technologies (GPS, variable rate applicators, optical sensors, etc.) are currently available that provide producers with application options. Currently, very few precision agricultural technologies are used in peanut production. A potential technology that could be used to target applications of fungicide to high disease pressure areas is remote sensing (aerial photos). Aerial photos can be used to determine Normalized Difference Vegetation Index (NDVI), which is a simple numerical indicator that can be used to analyze remote sensing measurements and to assess whether the target being observed contains live green vegetation. In 2009, one peanut field in Caddo County was identified that had visual evidence of Sclerotinia. Early observations indicate that it looks promising that we can identify areas of higher Sclerotinia pressure from near-infrared reflectance (NIR) or other aerial photographs. This should enable us to target applications of fungicide to control the highest disease areas. In addition, some areas of the field may not need to be treated or could be treated with a reduced rate of fungicide. Depending on pressure level of disease in a field, it is believed that we may be able to reduce Sclerotinia fungicide application costs by 15% – 35%. This is a very early estimate but savings should be realized. Implementation of this on a producer level should be relatively inexpensive since most agricultural retailers have the capability to make variable rate prescription maps and apply products variably. If producers do their own spraying, costs to get set-up to make variable rate applications should be relatively inexpensive and costs could easily be recouped from fungicide savings. The objective of this project is to evaluate the potential for variable rate application of fungicide to control Sclerotinia.