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ARS Home » Southeast Area » Stoneville, Mississippi » Crop Genetics Research » Research » Publications at this Location » Publication #317412
Title: Effect of tillage, cultivar and fungicide on Phomopsis longicolla and Cercospora kukuchii in soybean

Author
item Mengistu, Alemu
item Bellaloui, Nacer
item Arelli, Prakash
item YOUNG, HEATHER - University Of Tennessee
item Reddy, Krishna

Submitted to: Crop Protection
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/12/2014
Publication Date: 3/23/2015
Citation: Mengistu, A., Bellaloui, N., Arelli, P.R., Young, H., Reddy, K.N. 2015. Effect of tillage, cultivar and fungicide on Phomopsis longicolla and Cercospora kukuchii in soybean. Crop Protection Journal. 72:175-181.

Interpretive Summary: It has become a standard practice for farmers to use a no-till production system where crop residue are left on the soil surface rather than incorporated into the soil. This practice helps reduce soil erosion, conserve energy, increase soil moisture, and reduce erosion. However, many plant pathogens survive in the previous year's crop residue, increasing disease risk under reduced-tillage conditions. The effect of tillage on seed borne diseases has not been objectively evaluated in side by side comparisons of tilled and no-till study. A field study was conducted at the University of Tennessee, Milan Research and Education Center located in Milan, TN from 2007-2010 to determine the severities of Phomopsis Seed Decay and Purple Seed Stain in tilled and no-tilled plots treated with fungicide at beginning pod and beginning seed stage. Analysis of variance indicated there was no significant difference in Phomopsis Seed Decay and Purple Seed Stain infection due to tillage. However, fungicide significantly reduced Phomopsis Seed Decay in tilled but not in no-till plots. On the contrary, Purple Seed Stain increased in both tilled and no-till plots with fungicide application. These results suggest that fungicide programs under both till and no-till system may alter the level of severity of these two seed borne diseases and may require further research to minimize the risk.

Technical Abstract: It has become a standard practice for farmers to use a no-till production system where crop residue are left on the soil surface rather than incorporated into the soil. This practice helps reduce soil erosion, conserve energy, increase soil moisture, and reduce erosion. However, many plant pathogens survive in the previous year's crop residue, increasing disease risk under reduced-tillage conditions. The effect of tillage on seed borne diseases has not been objectively evaluated in side by side comparisons of tilled and no-till study. We evaluated the impact of tillage and foliar fungicide on percent seed infection by Phomopsis Seed Decay (PSD) and purple seed stain (PSS) over 4 years at the Milan Research and Education Center, Milan, TN. Analysis of variance indicated there was no significant difference (P=0.05) in PSD and PSS infection due to tillage. However, there was a significant interaction between fungicide and tillage where fungicide significantly reduced PSD in tilled but not in no-till plots. On the contrary, PSS increased in both tilled and no-till plots with fungicide application. These results suggest that fungicide programs under both till and no-till system may alter the level of severity of these two seed borne diseases and may require further research to minimize the risk.