Location: Crop Production and Protection
Project Number: 0500-00102-001-056-S
Project Type: Non-Assistance Cooperative Agreement
Start Date: Jun 1, 2024
End Date: May 31, 2025
Objective:
The goal of this project is to develop and validate disease and mycotoxin prediction tools to maximize the efficacy of management decisions and consequently reduce yield losses in corn.
Approach:
The project goals are conducted in two objectives: 1) Establish the association between inoculum intensity, production factors, disease development and weather in experimental plot trials; and 2) Disseminate corn disease information and management techniques through various outputs. In order to achieve objective 1, the work will focus on the following diseases: northern corn leaf blight (NCLB), gray leaf spot (GLS), southern rust (SR), tar spot (TS), and Gibberella ear rot (GER). Experimental plot trials will be established in corn fields at three locations in Arkansas to investigate associations among disease (GLS, NCLB, SR, TS and GER) intensity and the following factors: (1) planting date, (2) fungicide application at VT/R1, and (3) airborne inoculum density. For planting date, half of the field will be planted at the recommended planting date for the location (mid-late April) while the other half of the field will be planted four weeks later (mid-late May). A foliar fungicide will be applied at VT/R1 to half the plots, while no fungicide will be applied to the other half of the plots. Spore traps will be placed in the center of each field to monitor airborne inoculum density. Prior to planting, the amount of maize residue on the soil surface will be estimated as a measure of the percentage of the surface covered with residue in each residue block using a line transect method with 5 transects per residue block. Corn residue samples, consisting of 4-6 pieces of leaves and leaf sheaths, will be collected at 20 approximately equally spaced points along the line transect method described above (5 samples per transect) and bulked into a single composite sample per field. Samples will be air-dried as needed, weighed, paper-bagged, labeled and shipped to a cooperator for DNA extraction and qPCR analysis. Solar-powered single vial cyclone samplers and a low-cost spore trap with Vaseline-coated microscope slides will also be deployed at each field. Sample vials and slides from each trap will be collected/replaced at weekly intervals, and stored at - 20C. At the end of the growing season, sample vials or slides will be shipped overnight to a cooperator for DNA extraction and qPCR analysis. For disease assessment, GLS, NCLB, SR, and TS intensity will be rated bi-weekly on 10 arbitrarily-selected plants in the two center rows (4 and 5) of each plot. Ear rot will be identified, and severity estimated as a percent of kernels with signs and symptoms of ear rot. For mycotoxin assessment, grain samples will be collected from plots at harvest and shipped to a cooperator in Louisiana for mycotoxin contamination analysis. In order to achieve objective 2, data from these trials will be shared at two field days throughout the growing season and workshops during the winter. Data on estimated yield losses due to disease will be contributed to the Crop Protection Network for their Disease Loss Calculator. Corn disease management content for national and local websites will be developed.
