Thursday, September 28, 2017

Pecan cultivars that split shucks in late September

Osage, 28 Sept. 2017
   I spent a sunny afternoon looking over our pecan crop and photographing pecan cultivars that have split open their shucks since last week. I found 12 cultivars fully ripe (photo as right and below).
    As you look over the photos you can spot the cultivars that are susceptible to pecan scab. The 12 pecan cultivars that ripened this week can be broken down into three categories when it comes to pecan scab; resistant, susceptible but clean, and susceptible with scab lesions. The "susceptible but clean" cultivars are mildly susceptible to scab allowing our fungicide spray program to completely control the disease. The "susceptible with scab lesions" have a greater degree of susceptibility to scab infection and our spray program did not provide perfect control. Below is a list of the cultivars that ripened this week divided into the three scab susceptibility categories.

Resistant:   Norton, Osage, Shepherd

Susceptible but clean:  City Park, James, Posey, Surecrop, USDA 75-8-5

Susceptible with scab lesions: Canton, Colby, Witte, USDA 64-11-17

Norton, 28 Sept. 2017

James, 28 Sept. 2017

Colby, 28 Sept. 2017
City Park, 28 Sept. 2017

Canton, 28 Sept. 2017

Posey, 28 Sept. 2017

Shepherd, 28 Oct. 2017
Surecrop, 28 Sept. 2017

Witte, 28 Sept. 2017

USDA 64-11-17, 28 Sept. 2017

USDA 75-8-5, 28 Sept. 2017