IMPACT OF BAHIAGRASS, COTTON, AND CORN CROPPING FREQUENCY ON THE SEVERITY OF DISEASES OF PEANUT

1. IMPACT OF BAHIAGRASS, COTTON, AND CORN CROPPING FREQUENCY ON THE SEVERITY OF DISEASES OF PEANUT A. K. Hagan, L. H. Campbell, J. R. Weeks, M. E. Rivas-Davila Dept. of Entomology and Plant Pathology B. Gamble Wiregrass Research & Extension Center

2. Impact of Bahiagrass, Cotton, and Corn Cropping Frequency on the Severity of Diseases of Peanut • Peanuts have been a major cash crop for Alabama, Georgia, and Florida. • 1981 Farm Bill abolished the tie between quota poundage and acres, which encouraged an increase in peanut acreage at the expense of rotation. • Seen gradual decline in yield in Alabama starting in 1984 or 1985. • 2002 Farm Bill eliminated quota price support system. • Possibility of lower farm income plus high production costs may trigger a decline in peanut production, particularly on poorly-rotated land where yield potential is low.

3. 4 Good Reasons for theRecent Yield Decline in Peanut Southern Stem Rot • EARLY LEAF SPOT • LATE LEAF SPOT • SOUTHERN STEM ROT • PEANUT ROOT-KNOT Peanut Root-Knot Southern Stem Rot Early and Late Leaf Spot

4. OBJECTIVE • Evaluate the profit potential of cropping patterns where peanut is rotated with bahiagrass, corn, cotton, as well as several other forage crops. • Assess the impact of cropping frequency on diseases and nematode pests of peanut. • Monitor pest systems in other rotation crops.

5. Impact of Bahiagrass, Cotton, and Corn Cropping FrequencyMaterials and Methods • Established in 1986 on a site previously cropped to bahiagrass. • RCB design with four replications. • Plots consisted of twelve 30 ft rows on 3 ft centers. • Plots were watered with side-roll irrigation system as needed. • Planting and harvesting operations for each crop scheduled to coincide with time for optimum yields. • Grades for peanuts also recorded.

6. SSR Bahiagrass Rotation Patterns1986-2002 P=PEANUT, C=CORN, B=BAHIAGRASS

7. Rotation Patterns 1994 - 2002 P=PEANUT, C=CORN, CT= COTTON, PM=PEARL MILLET, V= VELVETBEAN, F=SUMMER FALLOW, R/= WINTER RYE.

8. CULTIVAR SELECTION • Peanut ‘Florunner’ replaced by ‘Georgia Green’ in 1998. • Cotton ‘DPL 555 B/RR’ for last three years. • Corn ‘DK 687 RR’ • Rye ‘Wrens Abruzzi’

9. TARGET PEANUT DISEASES Early Leaf S pot Late Leaf Spot TSWV Peanut Root-Knot Southern Stem Rot

10. Impact of cropping pattern on the severity of leaf spot diseases on ‘Georgia Green’ peanut. Cropping patterns listed above are for 1997 through 2002 growing season.

11. Impact of cropping pattern on the incidence of Southern stem rot on ‘Georgia Green’ peanut. Cropping patterns listed above are for 1997 through 2002 growing season.

12. Effect of the cropping frequency of bahiagrass, corn, cotton, and peanut on pod yield CROP CODE: P=PEANUT, B= BAHIAGRASS C=CORN, CT= COTTON

13. Effect of the crop selection in a 2-year rotation pattern on the yield of peanut P=PEANUT, B= BAHIAGRASS C=CORN, CT= COTTON, PM=PEARL MILLET, V= VELVETBEAN, F=SUMMER FALLOW, R/= WINTER RYE

14. Disease Summary • Leaf spot ratings on peanut increased as the interval between crops declined from 2 years to 0 in the peanut monoculture. • SSR incidence in the peanut monoculture was similar and sometimes lower than those where peanut followed one, two, three, and sometimes four years of a non-host crop like bahiagrass. • In 2002, SSR loci counts were higher where peanut followed 1 year of pearl millet, velvetbean, summer fallow, cotton, and bahiagrass but not corn.

15. Yield Summary • Frequency of peanut, corn, cotton, and bahiagrass production often had a significant impact on peanut yield. • However, peanut yield did not consistently increase as the interval between crops was lengthened. • Where peanut followed one year of a non-host crop, significant yield gains were obtained in two years with velvetbean, rye/summer fallow, and two of three years corn compared to the peanut monoculture.

16. Yield Summary • In one of two years, yield was higher in peanut cropped after one year of bahiagrass, pearl millet, cotton, or summer fallow. • Yield gains in the longer rotations was erratic. • Peanut grown after two years of bahiagrass and three years of cotton yielded nearly the same as the peanut monoculture. • Yield gains were seen where peanut were produced after two years of corn, cotton, or both crops, three years of corn, and three or four years of bahiagrass. • Peanut after three or four years of bahiagrass often had higher yields than the two-year cropping patterns. • The peanut-corn-peanut rotation looked pretty good.

17. IN PROGRESS • Analysis of peanut root-knot juvenile counts and root-knot damage ratings on peanut roots and pods. • Assess the impact of crop rotation on the incidence of TSWV in peanut. • Impact of crop rotation on the yield of cotton and corn. • Economic analysis of cropping patterns in an irrigated production system.