Managing Pecan Nut Casebearer in the Southeast

1. Managing Pecan Nut Casebearerin the Southeast Ted E. Cottrell USDA, Agricultural Research Service Southeastern Fruit and Tree Nut Research Laboratory 21 Dunbar Road, Byron, GA 31008 Ted.Cottrell@ars.usda.gov

2. Photo Acknowledgments • Bill Ree – Texas A&M • Jerry Payne – USDA, ARS (retired) • All the photographers with PNC photos on the internet that I have used.

3. Managing PNC in the Southeast • The pecan nut casebearer, AcrobasisnuxvorellaNeunzig, is the number one insect threat to pecan production in Texas. • PNC is not the #1 insect threat to pecan production in Georgia! • This nut feeder accounts for total crop losses in many years on unsprayed trees • in Texas, not in Georgia!! • But with proper timing of a labeled insecticide, economic losses can be minimized • and if you don’t need to treat, but do so anyway (just to be safe!), economic losses can be maximized.

4. PNC – Life Cycle

5. PNC – Life Cycle • Females lay eggs on pecan nutletssoon after pollination • Eggs hatch within 4-5 days

6. PNC – Life Cycle • Newly hatched larvae first feed on nearby leaf buds for a day or two before moving back to, and entering, the nutlet.

7. PNC – Life Cycle • Larvae feed for 4-5 weeks and pupate within the nutlet. • Infested nutlets exhibit larval frass and silk extruding from the entry hole.

8. PNC – Life Cycle • There are 2-4 PNC generations per year • 1st generation • 2nd generation: occurs in mid-summer • 3rd generation: feed on shucks if shells have hardened • 3rd/4th generation: larvae do not feed but build a hibernaculum at the base of a dormant bud and overwinter. Next spring, larvae emerge and feed by tunneling in shoots. They pupate in shoots or bark crevices. Moths emerge to lay eggs on nutlets.

9. Managing PNC….in a nutshell(1st generation) • Pheromone traps • 3 to 5 traps per orchard (< 50 acres); 5 traps if > 50 acres. Spread traps out. Place each trap near a nut cluster. • Put out traps by mid-April (earlier in south GA). • Sample traps every 3-4 days and at least 3x per week for adult PNC moths. Plenty of photos on the web to help you ID PNC adults! Pecan bud moth PNC

10. Managing PNC….in a nutshell(1st generation) • Scout orchard for PNC eggs on nutlets7-10 days after capturing the first PNC adult in a trap. Use a hand lens to aid in this process. • If an insecticide treatment is needed, it is typically applied to the orchard 2 weeks after the first male moths are captured in traps. • Do not apply insecticide due to high trap capture. • If an application is even warranted, application based on high trap capture usually results in the application being made too early to provide needed residual activity for PNC control. • Trap capture (low or high) DOES NOT indicate whether an insecticide needs to be applied.

11. Tips for scouting PNC • Start scouting for PNC eggs on nutlets7-10 days after capturing the first PNC in pheromone traps. • Examine 10 nut clusters/tree on 31 trees • If you find ≥ 2 infested clusters (eggs or nut entry) before sampling all trees, apply an insecticide within the next few days. • Mark some infested nut clusters with ribbon to determine egg hatch. Newly laid eggs are white but turn pink/red before hatching. Apply insecticide 1-2 days after egg hatch. • Scout for infested clusters again 5-7 days later. • If you find < 2 infested clusters, sample again 2-3 days later. • If you then find ≥ 2 infested clusters, immediately apply treatment. • If no treatment is needed, sample again 2 days later. This sample is very important if weather conditions have been cool or rainy.

12. 2012 PNC Trap Capture, Byron, GAAverage Daily Capture Data Average Moths / Trap Data collected from 3 PNC traps/orchard

13. 2012 PNC Trap Capture, Byron, GACumulative Data Is trap capture an indicator of the amount of future damage? Cumulative Capture of PNC Moths Over Time Data collected from 3 PNC traps/orchard

14. Percentage PNC Infestation of Nut Clusters inUnsprayed Pecan OrchardsMay 31, 2012 Trap capture is not an indicator of the amount of future damage!! Percentage of Clusters 1.5% 2.0% 1.3% Sampled 20 nut clusters per tree on 20 trees in each orchard

15. A place for a whole lot of pecan production information: pecan.ipmpipe.org/

18. For your consideration: • Some of the nuts you save from PNC will drop in June. • Heavy/Light crop. • The cost of traps/lures and scouting will pay you in pesticide and fuel savings. • Spraying for PNC ‘just to be safe’ is another way to redistribute your wealth. • SO…….. • You may need to treat your orchard for PNC. OR • You may not need to treat your orchard for PNC. • Trapping adult moths and scouting for eggs/nut entry will let you make that decision with confidence!