Effect of Tillage System, Phorate, and Cultivar on Tomato Spotted Wilt of Peanut
- J. J. Marois *a and
- D. L. Wrightb
Tomato spotted wilt (TSW) has become a limiting factor to peanut (Arachis hypogaea L.) production in the southeast United States over the past 6 yr. Cultivars are now selected based on their resistance to TSW and planted during time periods to reduce the incidence of TSW. Three peanut cultivars with different resistance to TSW were used (‘Georgia Green’, ‘MDR98’ and ‘SunOleic 97R’). Conventional- or strip-tilled plots were established after winter wheat (Triticum aestivum L.) in 2000 and 2001 in Marianna, FL. Stand count, severity of TSW, and yield were recorded. Plots were irrigated as needed. Stand count was 10% less in the strip-tilled plots in both 2000 and 2001. Stand count was affected by cultivar used, with Georgia Green and SunOleic 97R having 20% higher populations than MDR98. Phorate [O,O-diethyl,S-(ethylthio)methyl phosphorodithioate] treatment had 7% less stand count in 2001 but not in 2000. Tomato spotted wilt severity was 50% less in strip-tilled plots in 2000, but there was no difference in 2001. Cultivar affected severity of TSW every year but not consistently. Application of phorate did not affect TSW. In 2000 (a droughty year), the strip-tilled plots had greater yield (2510 vs. 1900 kg ha−1) averaged across cultivars. MDR98 had the highest yield across treatments in 2000, but yield was not different among cultivars in 2001. Application of phorate did not affect yield in either year. In the strip-tilled plots, soil moisture was 30% greater and plant canopy 3 to 5°C cooler during 2000 when plants were visibly drought stressed. Use of phorate had no effect on TSW or yield and its use for TSW control is not recommended. Cultivar selection did influence TSW severity and should be considered as part of a TSW control program. Strip tillage resulted in greater yields than conventional tillage in an abnormally dry year.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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