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United States Department of Agriculture

Agricultural Research Service

Title: Disease Management and Variable Planting Patterns in Peanut

Authors
item Nuti, Russell
item Faircloth, Wilson
item LAMB, MARSHALL
item SORENSEN, RONALD
item Davidson, James - RETIRED ARS
item Brenneman, Tim - UGA

Submitted to: Peanut Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: October 1, 2007
Publication Date: January 3, 2008
Citation: Nuti, R.C., Faircloth, W.H., Lamb, M.C., Sorensen, R.B., Davidson, J.I., Brenneman, T. 2008. DISEASE MANAGEMENT AND VARIABLE PLANTING PATTERNS IN PEANUT. Peanut Science. (1):11-17.

Interpretive Summary: Peanuts are usually grown in single or twin rows centered on 91 cm beds. A planter capable of sowing 8 rows of peanuts on a 182 cm bed was developed at the USDA-ARS National Peanut Research Laboratory. This planter spaces seed evenly in a diamond pattern in order to get more optimal plant spacing. With the diamond-pattern, peanuts will overlap 10 to 14 days sooner than peanuts planted in single or twin rows. The earlier that peanut plants overlap, they can help decrease evaporation from the soil and shade out small weeds. The diamond pattern places peanuts away from each other, which will reduce early competition for resources between peanut plants. This may help them mature sooner compared to peanuts planted closely together in a row. Management of soil borne diseases in peanut may be affected by planting patterns. In this study, three disease strategies were factored over single row, twin row, and diamond planting patterns, for a total of 9 treatments. The first disease strategy was based on a 10 to 14 day calendar schedule starting with three chlorothalanil applications followed by four tebuconazole applications. The second disease management strategy followed a weather-based advisory program called AUPnut. AUPnut uses chlorothalanil when recommended during the first 49 days after planting (DAP), tebuconazole between 50 and 100 DAP, and chlorothalanil after 101 DAP. The third disease management strategy incorporated minimum soil temperature with AUPnut recommendations to determine which fungicide to use for disease control from July 1st until harvest. Tebuconazole was selected when minimum soil temperature was below 21.1 C and above 23.8 C to target Rhizoctonia solani (peg, pod, and limb rot) and Sclerotium rolfsii (stem rot), which are more prevalent with lower and higher minimum soil temperatures, respectively. Chlorothalanil, which costs less, was selected to control Cercospora arachidicola and Cercosporidium personatum (early and late leaf spot) when minimum soil temperature was between 21.1 and 23.8 C. Field experiments were done in 2002, 2003, and 2004 at two locations each year on Americus and Faceville soil types in Terrell county Georgia. Peanut variety ‘Georgia Green’ was planted at 124 kg/ha to establish single row, twin row, and diamond pattern plots. Each planting pattern had the same number of plants per square meter. Acephate was applied in-furrow at planting in all treatments because the diamond planter does not have a system for delivering granular insecticides. A two-row KMC digger/inverter was adapted to effectively dig peanuts for the diamond planted plots. Planting patterns did not affect how the fungicide programs worked. Twin and diamond planting patterns yielded more than single rows, but diamond planting did not yield better than twin rows. The calendar fungicide program was consistently better for yield and disease control than the two advisory programs. Peanut grade was improved by diamond planting in one of the six experiments. In these experiments, there was little disease caused by R. solani and S. rolfsii and it was not affected by planting pattern.

Technical Abstract: Peanut is typically sown in single or twin rows centered on 91 cm beds. A planter capable of sowing 8 rows of peanuts on a 182 cm bed was developed at the USDA-ARS National Peanut Research Laboratory. This planter spaces seed evenly in a diamond pattern in order to optimize plant spatial relationships. A diamond-pattern seed placement usually results in achieving ground cover 10 to 14 days sooner than peanuts planted in single or twin rows. This benefit will conserve soil moisture, decrease the survivability of competitive plant species, and improve yield. Reducing early competition for resources between peanut plants may contribute to earliness. Management of soil borne diseases in peanut may be affected by planting patterns. Three disease strategies were factored over single row, twin row, and diamond planting patterns, for a total of 9 treatments. The first disease strategy was on a 10 to 14 day schedule starting with three chlorothalanil applications followed by four tebuconazole applications. The second disease management strategy followed the weather advisory program, AUPnut, using chlorothalanil when recommended during the first 49 days after planting (DAP), tebuconazole between 50 and 100 DAP, and chlorothalanil after 101 DAP. The third disease management strategy incorporated AUPnut recommendations with minimum soil temperature to determine product selection for disease control from July until harvest. By soil temperature readings, tebuconazole was selected when minimum soil temperature was below 21.1 C and above 23.8 C to target Rhizoctonia solani and Sclerotium rolfsii, which are more prevalent with lower and higher minimum soil temperatures, respectively. Chlorothalanil, which is a more affordable product, was selected to maintain suppression of Cercospora arachidicola and Cercosporidium personatum when minimum soil temperature was between 21.1 and 23.8 C. Replicated field experiments were conducted in 2002, 2003, and 2004 at two locations each year on Americus and Faceville soil types in Terrell county Georgia. Peanut cultivar ‘Georgia Green’ was sown at 124 kg/ha to establish single row, twin row, and diamond pattern plots with a uniform number of plants per linear unit of row between treatments. Acephate was applied in furrow at planting in all treatments because the diamond planter does not have a system for delivering granular insecticides. A two-row KMC digger/inverter was modified in order to effectively dig peanuts evenly spread over a 182 cm bed for the diamond planted plots. There were no planting pattern by fungicide program interactions. Twin and diamond planting patterns were superior in yield than single rows; however, diamond planting did not yield better than twin rows. The calendar fungicide regime was consistently better for yield and disease control than the two advisory programs. The diamond planting pattern improved grade in one of six trials. Incidence of R. solani and S. rolfsii were not severe in any trial and were not affected by planting pattern.

Last Modified: 8/19/2014
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