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AgriLife Entomologists Help Pecan Growers Battle Damaging Pest with Updated Web Application
Timing is of an essence when protecting pecan orchards from the damaging pecan nut casebearer moth.
The pecan nut casebearer larvae (caterpillars) eat the pecan nutlets and can reduce the yield from pecan trees. The pecan nut casebearer is the most damaging pest that attacks pecan crops in Texas. The moths are usually controlled by a single, well-timed insecticide application during the spring months.
Pecan nut casebearer moths, which are around 1/3 of an inch long in the adult stage, lay up to 150 eggs on tips of developing nutlets. The eggs then hatch and the larvae tunnel into the nutlets after pollination, destroying all nuts in the cluster.
This year, with help from Texas AgriLife entomologists, pecan producers have been using a new prediction system and an interactive web site to help determine when to survey their orchards for casebearer eggs and the optimum time to apply an insecticide, if needed, to control this pest.
Named the PNCforecast system, the site is a collaborative effort between Allen Knutson, Professor and Extension Entomologist, Mark Muegge, Associate Professor and Extension Entomologist, John Jackman, Professor and Extension Entomologist, Bill Ree, Extension Program Specialist-IPM, Professor Marvin Harris, and website designer Rob Williams.
The PNCforecast system, located at pncforecast.tamu.edu, uses a model based on temperature data and pheromone traps to predict when the pecan nut casebearer moths will be ovipositing (laying eggs) in the orchard and when subsequent larvae first begin tunneling into pecan nuts in the spring. Knutson, Muegge and Ree validated the PNCforecast system during 2007 in orchards in central and west Texas and are continuing to validate the model this year in Texas and Oklahoma.
The system helps growers anticipate the appearance of this annual pest and plan management strategies. The PNCforecast was developed by Knutson, Muegge and Jackman, and is a result of ten years of field studies conducted by Knutson and Muegge. .
Pecan growers can use historical temperature data from nearby orchard locations or the grower can update PNCforecasts by entering actual temperature from his orchard starting with the first moth catch. Knutson said the actual temperature data should improve model accuracy in years with unusual temperatures, like 2008 when average temperatures have been above normal.
In addition to generating PNCforecasts unique to their orchards, pecan growers can view a map showing PNCforecasts generated at more than 25 locations in Texas. Extension faculty and grower-cooperators monitor traps at these sites and provide trap data needed to generate local PNCforecasts, Knutson said. This network of cooperators has expanded from an initial network created by Ree and Harris.
Results have shown the PNCforecast system is another valuable tool in the pecan IPM tool box. As with any model, treatment decisions should not be made using only the PNCforecast system but predictions should be confirmed with actual orchard scouting to assess pest infestations and the need for and timing of insecticide treatments.