Over several years, trials show a 500-pound average advantage of controlling leaf spot. “In dry years, we see little gain, but in a wet year we get more than a 1,000-pound advantage. It is important to control leaf spot with a high yield goal.”

Damicone said other control techniques are under consideration or in use. A leaf spot advisory program using Mesonet data to indicate likelihood of conditions favoring leaf spot infection may help farmers decide on control options. “It’s also important to get into the field. Scout and know the field,” he said.

Managing the primary soil-borne diseases also requires knowing the field, Damicone said. “Base control strategy on field history. Infection may occur from mid-season (mid-July) until mid-September. “If a farm has problems, it pays to control.”

He said pod rot “is hard to deal with, but we do have good fungicides—Abound and Ridomil. Calcium fertility and variety resistance also help.”

He said Virginia types are vulnerable to pod rot.

Controlling Sclerotinia blight begins with evaluating field history, Damicone said. “Also look at variety selection and fungicide options. With Virginia peanuts or a history of Sclerotinia in the field, use a fungicide or risk severe yield reductions.  Treat based on symptoms; apply a fungicide when you first see symptoms. The disease may come in from July through September.”

Fungicide choices include Omega, Endura, Propulse and Fontelis. He said Omega and Endura “generally provided the best disease control. Most treatments numerically increased yields, compared to the untreated check.”

He said one plot with severe deer damage provided limited data.

Damicone is also looking at response to numerous breeding lines to fungicide programs.

He summarized disease management trials in a publication “Peanut Research at OSU 2013.”

Findings included:

  • New fungicides Fontelis and MCW 710 provided excellent leaf spot and southern blight control, resulting in yield response of more than 1,000 pounds per acre on Spanish peanuts.
  • Two fungicides recently registered for peanuts (Fontelis and Propulse) did not have consistent activity against Sclerotinia blight when applied alone or in alternation with each other, compared to Omega and Endura.
  • Under low pressure from Sclerotinia blight, the varieties Florida-07 and Red River Runner produced the highest yields and crop value ($ per acre).
  • Runner (ARSOK-R30) and Spanish (ARSOK-S140-10L) breeding lines from the USDA/ARS breeding program showed excellent resistance to Sclerotinia blight and had the highest yields and grade.
  • Calendar (six applications) and weather-based (three application) programs increased yields of Spanish peanuts by more than 1,000 pounds per acre where early leaf spot was severe.

Integrated approach critical for resistant weed control

Damicone said farmers should consider all the disease management tools available, beginning with rotation and field history in making disease control plans for any year. And protection remains the key for leaf spot.

 

Also of interest:

Ole Spanish peanut fills a niche

USDA amendment would add Arkansas as Primary Peanut-Producing State

Peanut butter controversy not over yet