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| GROWER'S CORNER: FOR GROWERS, BY GROWERS |
Impact of Cropping Frequency on the Severity of Diseases and Insect Pests and on the Yield of Peanuts
Disease and Pest Resistance
A. Hagan |
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| Researchers determined that leaf spot and southern stem rot damage declined as the interval between peanut crops increased to three years. One year of peanuts followed by at least two years of bahia grass or three years of corn or cotton showed light to moderate spotting of leaves and a low level of defoliation. In contrast, heavy leaf spotting and 50 percent defoliation was recorded where peanuts were cropped for a minimum of three successive years.
Southern stem rot hit counts declined steadily from an average of 29.1 in continuous peanuts to 18.7 where peanuts were cropped on a three-year rotation with corn, cotton or bahia grass.
Among the one-year rotations, the peanut-summer fallow cropping sequence worked best at suppressing southern stem rot. Crop selection had a significant impact on southern stem rot damage levels and peanut yield in a one-year rotation. Compared to cotton, velvetbean, corn, and summer fallow, pearl millet proved ineffective in suppressing southern stem rot in a one-year rotation. Pod yield for the peanut-pearl millet sequence was well below those noted for the other one-year rotations and was similar to those recorded for continuous peanuts.
While the least southern stem rot damage was seen where peanut followed two years of bahia grass, pod yields recorded for all two-year rotations were similar except the corn-corn-peanut sequence. Average pod yield for all the two-year and three-year rotation sequences were 800 to 900 lbs/A above those noted for continuous peanuts.
In 2000 and 2001, considerable differences in peanut root-knot could not be seen regardless of the frequency of peanut production. Root-knot larval counts were equally low in corn, cotton, bahia grass, pearl millet, and velvetbean crop.
In contrast, root-knot populations usually rebounded to damaging levels, especially in the one-year rotation of peanuts, behind corn, cotton, or bahia grass, or any time peanuts follow one or more years of peanuts.
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