Pecan growers can now use a new Web site to predict insect pest activity in their orchards and track activity across the state, say entomologists with the Texas AgriLife Extension Service.

They have developed the PNCforecast System, an on-line model that uses pheromone traps and temperature to predict when pecan nut casebearers will be active in pecan orchards in the spring, says Allen Knutson, an entomologist with the Texas AgriLife Research and Extension Center at Dallas.

The new system is available from AgriLife Extension at http://PNCforecast.tamu.edu.

The pecan nut casebearer, or PNC, is the most damaging pest attacking pecans in Texas, Knutson says. A single, well-timed insecticide application in the spring is usually sufficient to prevent crop loss. But knowing when to make this application is the challenge.

The PNCforecast system helps growers anticipate the appearance of this annual pest and plan management activities, he says. The system uses the pheromone traps to determine when the first pecan nut casebearers begin to fly.

The PNCforecast system then uses that "first moth" date and historic weather data for the local site to predict when casebearer moths will be depositing eggs in the orchard and when larvae will begin to tunnel into nutlets.

"Knowing these time periods is critical to managing this pest," Knutson says. "Based upon the PNCforecast output, we know when to begin scouting the orchard to determine if casebearer infestations exceed the threshold."

An insecticide treatment, if needed, should be most effective if applied just prior to the date when the first larvae begin tunneling into the nutlets, he said. The PNCforecast System predicts this date, helping pecan growers plan.

But Mark Muegge, an Extension entomologist at Ft. Stockton, warns that the PNCforecasts are only that. Growers should base management decisions on actual assessment of casebearer infestations as determined by orchard scouting.

Knutson and Muegge developed the PNCforecast System based on field data collected over 10 years from orchards in north central and west Texas.

To use the PNCforecast system, growers need to know when casebearer moths are first captured in their orchards. Growers also need access to historic temperature data for their locations to make predictions.

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