Skip to main content
ARS Home » Plains Area » Mandan, North Dakota » Northern Great Plains Research Laboratory » Research » Publications at this Location » Publication #145808
Title: LEAF SPOT DISEASES OF SPRING WHEAT AS INFLUENCED BY PRECEEDING CROPS OF BARLEY, CANOLA, CRAMBE, DRY BEAN, DRY PEA, FLAX, SAFFLOWER, SOYBEAN, SUNFLOWER, AND SPRING WHEAT

Author
item Krupinsky, Joseph
item Tanaka, Donald
item Lares, Michael
item Merrill, Stephen

Submitted to: Agronomy Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/30/2003
Publication Date: N/A
Citation: N/A

Interpretive Summary: Management practices such as using different crops and crop sequences (the order in which crops are planted) can influence plant disease risk. Ten crops, barley, canola, crambe, dry bean, dry pea, flax, safflower, soybean, sunflower, and spring wheat, were planted in crop residue from the previous year to evaluate crop sequencing effects. The objective of this research was to determine the effect of ten preceding crops on spring wheat leaf spot diseases. Treatments varied in amount of crop residue carryover. The most common leaf spot diseases were tan spot and stagonospora nodorum blotch. Spring wheat was evaluated for leaf spot diseases twenty-two times over two years. Leaf spot diseases progressed more quickly and reached a higher level in 2000 compared to 1999. Differences among treatments were more detectable with earlier evaluations indicating a greater influence of crop residue and carryover of inoculum early in the season compared to later in the season. The risk for leaf spot disease was lower when wheat was grown after canola, barley, crambe, and flax than when grown after the other crops. The wheat-after-wheat treatment had the lowest yield.

Technical Abstract: Crop diversification and sequencing can influence plant disease risk in cropping systems. Ten diverse crops, barley, canola, crambe, dry bean, dry pea, flax, safflower, soybean, sunflower, and spring wheat, were planted in the crop residue of the same ten crops from a previous year to evaluate crop sequencing effects. The objective of this research was to determine the effect of ten previous crops on spring wheat leaf spot diseases. Treatments varied in amount of crop residue carryover. The most common leaf spot diseases were tan spot, caused by Drechslera tritici-repentis, and stagonospora nodorum blotch, caused by Stagonospora nodorum. Spring wheat was evaluated for leaf spot diseases 22 times over two years. The logistic model adequately described the disease progression on each leaf over two years. Overall, the slope of the disease progress curve, area under the curve and Y max were significantly higher in 2000 than in 1999. Differences among treatments were more detectable with earlier evaluations indicating a greater influence of crop residue and carryover of inoculum early in the season compared to later in the season. The risk for leaf spot disease was lower when wheat was grown after canola, barley, crambe, and flax than when grown after the other crops. The wheat-after-wheat treatment had the lowest yield.