By Derek Scasta
May 11, 2008 01:38 am
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Upcoming Events
May 16 Grazing Management Workshop — 8 a.m. to noon at 77 Ranch
May 31 Tire Disposal Day — 8 a.m. to 2 p.m. at the Precinct 1 Barn
June 7 County Wide CleanUp Day — 7 a.m. to 2 p.m. at the Corsicana Regional Landfill
Pecan Nut Casebearer Update for County Pecan Producers
Insect traps were established in two locations in Navarro County to collect data on the destructive pecan nut casebearer. The pecan nut casebearer, or PNC, is the most damaging pest attacking pecans in Texas, according to Dr. Allen Knutson, Extension entomologist. A single, well-timed insecticide application in the spring is usually sufficient to prevent crop loss. However, knowing when to make this application is the challenge. Data collected in Navarro County was utilized in the PNCforecast system to help growers anticipate the appearance of this annual pest and plan management activities, Knutson said.
According to trap results, April 28th was used as the date of first significant moth capture. It states that growers should begin scouting for eggs May 11-14, when we expect 25-50 percent of the eggs will be present. First nut entry is predicted for May 19, so insecticides should be applied before that date if an economic level of eggs are present. The spray date will depend on weather conditions and how long it takes to treat the orchard (as an example if three days, then should begin May 16 to be done by May 19). For backyard growers who are limited to insecticides with short residual, treating just before and at nut entry (May 17-19) may be beneficial.
As we state below, these are only forecasts. The information provided by this application is for educational purposes only. Treatment decisions should not be based solely on PNCforecast output. The PNCforecast can not account for differences in environmental conditions at weather stations and actual orchard conditions. Growers should base management decisions regarding PNC on their assessment of eggs and larvae in their orchards.
Forecasted Event Dates Percent Oviposition: 10 percent, May 8; 25 percent, May 11; 50 percent, May 14; 75 percent, May 17; and 90 percent, May 19; first nut entry, May 19.
The above information gives the dates when 10, 25, 50, 75 and 90 percent of the first generation eggs are expected to be present in the orchard. You can use this information to decide when to scout the orchard for eggs. Begin scouting on the dates of 25-50 percent oviposition. If egg numbers do not reach a treatment threshold, return and scout for eggs and larvae again on the dates of 50-75percent oviposition. If eggs and larvae numbers are still below threshold, scout a third time on the dates of 75-90 percent oviposition to determine if casebearer infestations have increased to a threshold level justifying an insecticide treatment. The date of first nut entry is the date when the first pecan nut casebearer larvae are expected to begin tunneling into nutlets. If egg numbers exceed the treatment threshold, an insecticide spray is best timed just before the date of first nut entry. Plan orchard spraying so that all trees have been treated on or before this date.
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