Integrated Disease Management of Leaf Spot and Spotted Wilt of Peanut

Abstract

Field experiments were carried out to evaluate the effects of integrated management of early leaf spot, caused by Cercospora arachidicola, and spotted wilt, caused by Tomato spotted wilt virus (TSWV), on peanut (Arachis hypogaea) using host resistance, two tillage systems, and varying fungicide programs. Effects on pod yield and economic return were assessed. Genotypes C-11-2-39 and Tifrunner demonstrated the best field resistance to TSWV, whereas cvs. DP-1 and GA-01R and line C-28-305 were among the genotypes with the best leaf spot resistance. Epidemics of both diseases were comparable or suppressed in strip-tilled plots compared with conventionally tilled plots. Leaf spot intensity decreased with increased fungicide applications, but to a lesser degree with use of resistance and strip tillage. Yields and net returns were similar between tillage treatments in 2002 and lower in strip tillage in 2003. Genotypes with the greatest yields and returns were C-11-2-39, C-99R, and GA-01R. Returns were comparable among the four-, five-, and seven-spray programs in both years, despite differences in yield. The standard production system, Georgia Green in conventional tillage with seven sprays, resulted in lower returns than half the integrated systems tested in 2002, but had comparable or higher returns than nearly all systems in 2003. When significant, yields and returns were correlated with spotted wilt intensity to a greater degree than leaf spot intensity.

Evaluation of New High Oleic Virginia-Type Peanut Cultivars for Disease Tolerance, Yield, and Quality

“…Due to slightly higher disease tolerance compared to Bailey, good agronomic characteristics, high yield and quality under a variety of growing environments, and the presence of the high-oleic trait, Sullivan is an excellent cultivar for Virginiatype peanut production in the Virginia-Carolina region. A lack of yield response to higher-input fungicide programs for Sullivan and Bailey demonstrates the value of incorporating disease resistance/tolerance in peanut breeding programs (Wynne et al, 1991;Monfort et al, 2004;Cantonwine et al, 2006;Chapin et al, 2010). Furthermore, high yields and net returns of Sullivan regardless of fungicide program suggests further reducing fungicide inputs during production of this and other disease resistant/tolerant cultivars may be possible under low to moderate disease pressures as suggested by previous studies (Phipps, 1993;Cantonwine et al, 2006;Woodward et al, 2010Woodward et al, , 2014.…”

“…A lack of yield response to higher-input fungicide programs for Sullivan and Bailey demonstrates the value of incorporating disease resistance/tolerance in peanut breeding programs (Wynne et al, 1991;Monfort et al, 2004;Cantonwine et al, 2006;Chapin et al, 2010). Furthermore, high yields and net returns of Sullivan regardless of fungicide program suggests further reducing fungicide inputs during production of this and other disease resistant/tolerant cultivars may be possible under low to moderate disease pressures as suggested by previous studies (Phipps, 1993;Cantonwine et al, 2006;Woodward et al, 2010Woodward et al, , 2014. Delayed fungicide applications are already recommended for Bailey (Balota et al, 2015), but fungicide advisories, including the weather-based advisories for leaf spot and Sclerotinia blight fungicide applications in Virginia (Cu and Phipps, 1993;Phipps et al, 1997;Langston et al, 2002), need to be re-evaluated for new cultivars with greater levels of disease tolerance.…”

“…As new cultivars with partial disease resistance are developed and released, the need for costly fungicide inputs to produce acceptable yields has decreased (Monfort et al, 2004;Cantonwine et al, 2006). The Virginia-type cultivar Bailey was released in 2011 (Isleib et al, 2011), and the partial resistance of this cultivar to diseases including late leaf spot, CBR, and Sclerotinia blight, as well as good yield and quality characteristics, has made this the cultivar of choice for growers in the Virginia-Carolina region.…”

“…Integrated disease management, which incorporates cultivar resistance, good cultural practices, and judicious use of fungicides, has been demonstrated to reduce overall fungicide costs and increase the profitability of peanut production (Phipps, 1993;Cantonwine et al, 2006;Woodward et al, 2010Woodward et al, , 2014. Weather-based disease advisory programs have reduced the number of fungicide sprays required for control of peanut diseases, thereby reducing total fungicide costs in peanut production, and leaf spot and Sclerotinia advisories for peanut are frequently utilized by peanut producers in the Virginia-Carolina region (Cu and Phipps, 1993;Phipps et al, 1997;Langston et al, 2002).…”

“…Weather-based disease advisory programs have reduced the number of fungicide sprays required for control of peanut diseases, thereby reducing total fungicide costs in peanut production, and leaf spot and Sclerotinia advisories for peanut are frequently utilized by peanut producers in the Virginia-Carolina region (Cu and Phipps, 1993;Phipps et al, 1997;Langston et al, 2002). Some studies have found that reducedinput fungicide programs can effectively manage diseases in cultivars with partial disease resistance or tolerance and result in overall greater profitability compared to standard, high-input fungicide programs (Monfort et al, 2004;Cantonwine et al, 2006;Woodward et al, 2014). Ultimately, weatherbased fungicide advisories may need to be revised to account for the higher levels of disease resistance in newer peanut cultivars, and there may be potential to further reduce fungicide inputs in peanut production.…”