Managing early leaf spot and stem rot with reduced fungicide inputs on disease-resistant peanut cultivars

Abstract

Fungicide inputs are a costly but critical component of peanut production systems in the southeast U.S. Current strategies for reducing fungicide application numbers that are needed to control diseases on peanut include extending application intervals beyond a 2-wk schedule or implementation of a fungicide advisory, such as AU-Pnuts. In this study, fungicide programs with azoxystrobin, chlorothalonil, and tebuconazole, using different application schedules, were compared for the control of early leaf spot and stem rot. Application schedules were the standard 2-wk calendar interval, extended 3- and 4-wk intervals, and applications were made according to the AU-Pnuts leaf spot advisory. Studies were conducted on the disease resistant cultivars DP-1 in 2003 and C-99R in 2004 and 2005. The numbers of fungicide applications for the 2, 3, and 4-wk schedules were 7, 5, and 4, respectively, in 2003 and 2004, and were 6, 5, and 4, respectively, in 2005. One less fungicide application was scheduled according to AU-Pnuts than with the 2-wk calendar schedule in all three years, yet final early leaf spot levels with these schedules were similar in 2 of 3 years. With one fewer fungicide application, the 3-wk schedule had higher leaf spot levels than the AU-Pnuts advisory in 2003 and 2004. Further, when application intervals were extended from 2 wk to 3 or 4-wk intervals, a significant increase in early leaf spot was noted in two of three years. Despite these differences in early leaf spot severity, application schedule had limited impact on yield in this study. Application interval also had little impact on stem rot incidence, but incidence of this disease was lower with the azoxystrobin than chlorothalonil programs in 2 of 3 years. The azoxystrobin program significantly increased yield in 2 of 3 years compared with the chlorothalonil or tebuconazole programs. Yield was also higher for the tebuconazole compared with chlorothalonil programs in 2 of 3 years. When fungicide product and application costs were calculated, and those and other typical peanut production costs were deducted from estimated returns based on actual yields, the resulting net returns did not significantly differ among fungicide programs or application schedules.

Diseases of Edible Oilseed Crops

“…The application of sterol biosynthesis inhibitors (SBI) also referred to as DMIs and quinone out side inhibitor (QoI) fungicides are now known to be more effective than previously recommended fungicides such as quintozene and carboxin for the control of SSR (Johnson and Subramanyam 2000, Besler et al 2006, Grichar et al 2010, Augusto and Brenneman 2011. The SBI tri azole systemic fungicides, namely, diniconazole, propiconazole, tebuconazole (Minton et al 1990, Culbreath et al 1992, Adiver and Anahosur 1995, cyproconazole (Culbreath et al 1992, Adiver andAnahosur 1995), hexaconazole (Johnson et al 2007b), difenoconazole (Cilliers et al 2003), and prothioconazole (Augusto and Brenneman 2012), and the QoI strobilurin fungicides, that is, azoxystrobin (Johnson and Subramanyam 2000, Rideout et al 2002, Sconyears et al 2007, Hagan et al 2010) and pyraclostrobin (Hagan et al 2007, Grichar et al 2010, have been proved to give very efficient and effective control of SSR of peanuts. The QoI fungicides should be applied preventively or as early as possible in the disease cycle as these are effective in inhibiting early mycelial growth.…”

Assessing the prospects of Streptomyces sp. RP1A-12 in managing groundnut stem rot disease caused by Sclerotium rolfsii Sacc

“…Though host-plant resistance is the most economically viable option to control this disease, unfortunately, all improved varieties in cultivation today are more or less susceptible to stem rot. Presently, stem rot is managed using chemical fungicides such as azoxystrobin, chlorothalonil, tebuconazole, carbendazim and mancozeb (Hagan et al 1991(Hagan et al , 2010, but their high cost keeps them from being a viable approach, especially for resource-poor smallholder farmers and where productivity is low (1.0-1.5 t/ha), especially in Asia and sub-Saharan Africa. On the other hand, sustainable and ecologically safe methods to manage soilborne pathogens are gaining popularity as concerns on the harmful effects of chemicals increase.…”

Integrated Management of Major Foliar and Soil-Borne Diseases of Peanut (Arachis hypogaea L.) with Fungicides, Trichoderma and Castor Cake

“…The PEDC (per cent efficacy over disease control) was also very high in T 3 in comparison to other treatments. Hagan et al, (2010) also reported azoxystrobin, chlorothalonil, and tebuconazole, for the control of ELS and stem rot and found the incidence of these diseases were lower with the application of azoxystrobin than chlorothalonil in the 2 out of 3 year"s programs. The azoxystrobin program significantly increased yield compared with the chlorothalonil or tebuconazole.…”