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INSECT UPDATE: Pecan Nut Casebearer

It’s that time again to be mindful about pecan nut casebearer (PNC) activity especially after the infestations reported by some growers last year.

We normally do not recommend spraying for nut casebearers particularly during high crop load years as they help in thinning out the crop, and only spraying for them after scouting for presence of eggs and larvae on nutlets. However, for those with previous infestations and for those who choose to spray for prophylactic reasons, the best time to do it using caterpillar materials such as Intrepid, Intrepid Edge and Dimilin is 10-14 days after onset of sustained moth activity.

In connection with this, together with USDA collaborators and several county agents across 15 pecan-growing counties in Georgia, we started monitoring for pecan nut casebearer activity starting around April 1, 2020 by using pheromone-baited traps (Figure 1). The traps are checked daily until PNC moths are captured consistently for two consecutive days, the first date of consistent captures is what we refer to as the biofix date.

Figure 1. Pheromone-baited trap used for monitoring pecan nut casebearer moths. Only male moths are captured using this technique.

The initial (biofix) dates of sustained moth flight activity across all monitored sites are reported via an online map along with the spray decision window.

https://maps.eddmaps.org/pncrisk/index.cfm?lat=31.75&lng=-83&zoom=9

Check the legend on the upper right corner of the map, and once biofix is established at a site, click or tap on the site to check for the spray decision window for that site. Based on my conversations with Dr. Lenny Wells, the nut/crop development is early this year, so I would suggest spraying for PNC earlier in the decision window, if possible.

Continue to check the map for updates in the monitored sites. We are expecting PNC moths to be active across south GA in the coming days.

For those who have put out PNC traps on their own, use this map to type in your biofix date (first date of sustained captures), drag the map point to your trap location and get the decision window for your location.

Thanks to our grower and county agent collaborators. Traps are checked by county agents each day of the week safely* during these difficult times: Michasia Dowdy (Brooks County), James Morgan (Daugherty County), Andrew Sawyer (Dodge County), Scout Carter (Ware County), Tucker Price (Cook County), Jeremy Kichler (Colquitt County), Joshua Grant (Crisp County), Shane Curry (Appling County), Aubrey Shirley (Tatnall County), Derrick Bowen (Tatnall County), Ben Reeves (Berrien County), Pamela Halliday (Tift County), Buck Paulk and Dr. Ted Cottrell. I am also grateful for Bugwood in helping us with the online mapping and for Trece Inc. for providing some trapping supplies.

*How safe? Trap checking at each site only takes <5 minutes by one person without interacting with anyone.