Impact of In-furrow Prothioconazole in Combination with Provost and

Artisan/Initiate Fungicide Treatments on Soilborne Diseases Tyson*, W. G.¹ , Kemerait, R. C.²

¹University of Georgia Cooperative Extension, Effingham County, Springfield, GA 31329

²University of Georgia, Department of Plant Pathology, 4604 Research Way, Tifton, GA 31794

Abstract Soilborne diseases are a critical problem for peanut producers in Effingham County and must be addressed

with additional on-farm research to establish “best management” practices. The producers’ current best line of

defense to combat these problems involves selection of more-resistant varieties, judicious use of fungicides,

and soil fumigation with metam sodium to reduce severity of Cylindrocladium black rot (CBR). Unfortunately,

foliar fungicides and more-resistant varieties are insufficient to manage CBR in Effingham County and our

growers are unlikely to use fumigation to manage the disease. In this study, the effectiveness of

prothioconazole (Proline) applied in-furrow at planting was evaluated for the management of peanut diseases.

Provost (prothioconazole + tebuconazole) and Artisan (flutolanil + propiconazole)/chlorothalonil were

evaluated with Proline (prothioconazole) to assess the best program for overall disease protection. Unlike

white mold demonstrations, this project is unique in that no research has been done on the management of

CBR in the Southeast. Data collected included severity of leaf spot diseases, white mold, Diplodia collar rot,

and Cylindrocladium black rot. As an in-furrow fungicide with known activity against CBR may also improve

seedling health, it was hoped that use of Proline might reduce seedling disease and TSWV as well. In-furrow

use of prothioconazole is a new practice for our peanut growers, and there is an important need data on this

product in the southeast from large-plot, on-farm trials. From the research in Effingham County, the

effectiveness of prothioconazole as a part of a disease management program to improve plant stand and

reduce other disease such as TSWV, CBR, and white mold has been addressed. These results will play an

important role in recommendations for future use of prothioconazole in the Southeast.

Introduction

Peanut producers in Effingham County battle the same diseases as do growers across Georgia and the

southeastern United States. Leaf spot diseases and white mold require growers to use effective foliar-

applied fungicide programs to reduce severity and increase yield potential in commercial fields.

Cylindrocladium black rot (CBR) is especially important for peanut farmers in Effingham County and can be

devastating in some fields. Management of CBR is a major priority for growers here and the University of

Georgia Cooperative Extension has conducted on-farm large-plot trials in 2008, 2009, 2010 and 2011 to

assess management strategies for peanut growers in Effingham County. The 2010 field study included an

assessment of the integrated use of foliar applications of prothioconazole + tebuconazole (Provost); in-furrow

and at-cracking applications of prothioconazole (Proline) and day-versus-night applications for the

management of important peanut diseases.

Symptoms of CBR include 1) patches of dead and dying peanut plants scattered in a field, 2) brick-red

fruiting structures (perithecia) and blackened stems and roots, and 3) “cinnamon” speckles on infected seed

(left seed in above picture).

Materials and Methods

The 2009, 2010 and 2011 studies were conducted in a commercial field known to be severely infested with

Cylindrocladium black rot (CBR). In 2009 and 2010, peanut seeds, ‘Florida-07, were planted in a twin row pattern. In

2011, ‘Georgia-07W’ peanut variety was planted in a twin row pattern. All production practices, to include fertility,

weed control, insect management, and disease management were according to recommendations from the University

of Georgia Cooperative Extension.

Two Proline treatments were assessed in the plot for efficacy. Proline was applied in-furrow at 5.7 fl oz/A at planting;

an additional 5.7 fl oz/A was applied to ½ of the in-furrow treated peanuts soon after emergence. Two foliar-applied

fungicide programs were assessed and were coupled with each Proline treatment. These were 4-block applications

of Provost, 10.7 fl oz/A, and Artisan (flutolanil + propiconazole) at 16 fl oz/A + Initiate, 16 fl oz/A. Day-versus-night

applications of the foliar-applied fungicides were also assessed in this study and the treatments were replicated

throughout the field. The “night” applications were typically made at 5:00 AM in the morning prior to sunrise. Prior to

harvest all plots were rated for soilborne and leaf spot diseases. Immediately after the peanuts in the field were

inverted, the plots were assessed for incidence of soilborne diseases – CBR and white mold. Multiple strips (200 ft.

each) were rated in each plot for disease.

Results

In the 2009 study an interaction was observed between in-furrow fungicide treatments and foliar fungicide applications

across the in-furrow fungicide treatments for leaf spot control. There was no significant interaction between in-furrow

fungicides and foliar applied fungicides. However, in 2009 there was a significant difference throughout the field on

soilborne disease (primarily CBR) control where Proline had been applied in-furrow. Differences were also noticeable

between Provost and Artisan/Initiate when applied over in-furrow treatments. At the time of this meeting, peanuts in the

2011 study remain to be harvested.

Conclusion

1. For management of CBR, Provost is preferred over Artisan.

2. Use of Proline in-furrow can benefit fungicide programs for improved control of CBR and improved yields.

3. The above is true EVEN IF rate (5.7 fl oz/A) is SPLIT under each twin-row (2.85 fl oz/A under each twin-row).

4. The additional use of Proline (5.7 fl oz/A) adds additional benefit for management of CBR and improved yield.

5. Use of Proline in-furrow and post-emergence applications provided significantly better control of CBR than when in-

furrow fungicide was not used. Two applications were numerically, but not statistically better than use of in-furrow

application alone.

6. Both the Provost program and the Artisan + Initiate program provided excellent control of early leaf spot; however,

the Provost program was statistically better.

7. This field trial documents the real potential for peanut growers in Georgia to better manage CBR with the use of

Proline fungicide.