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Poster: Diseases of Plants: Crop Loss Assessment


Assessing Goss’s bacterial wilt and leaf blight of corn in the High Plains of Texas with infrared aerial imagery.
J. WOODWARD (1), R. French-Monar (2), J. Todd (3), O. Moore (4) (1) Texas A&M AgriLife Extension, U.S.A.; (2) Texas A&M AgriLife Extension, U.S.A.; (3) Todd Ag Consulting, U.S.A.; (4) High Plains Consulting, U.S.A.

Outbreaks of Goss’s bacterial wilt and leaf blight of corn, caused by Clavibacter michiganensis subsp. nebraskensis, were reported in the Texas High Plains from 2013 to 2015. The disease was identified based on symptomology, bacterial streaming, colony characteristics and Immunostrip test results. Impact of the disease on corn is poorly understood in this region, thus the objective of this study was to evaluate disease development using aerial imagery. Fields were photographed from a fixed-wing aircraft from mid-July to late-September of each year. Images were effective at differentiating resistant and susceptible hybrids and improved scouting efficiency when assessing incidence and severity. Disease onset differed by location but initial infections were easily identifiable. In general, infection foci were non-random or aggregated; however, edge effects were observed in two areas adjacent to fields where the disease was observed the previous year and reduced tillage was implemented. Yield reductions ranging from 12 to 53% were observed in areas of some fields; whereas, other fields exhibiting >85% incidence were abandoned for grain production and cut for silage. These results indicate that Goss’s wilt has the potential to negatively affect corn production under favorable conditions. Increased awareness through educational materials, including information on hybrid selection, crop rotation and residue management has allowed for better management of the disease.