Tuesday, April 25, 2017
Pecan Nut Case bearer Spray Time Is Earlier than the past years
Pecan Nut Case bearer Spray Time Is Earlier than the past years Carlsbad, NM,— It is that time of the year again to be thinking about spraying for Pecan Nut Case bearer (PNC). Population projections are not very reliable this year because of the strange weather. We have not had a drop in minimum daily temperature since bud break in Pecans like those that we did last year. I estimated bud break to be March 30 this year but it varies up and down the valley. Some reported as early as March 26 and other as late as 10 April. Using a Heat unit model developed by Texas A & M Cooperative Extension Service, the Eddy County Cooperative Extension Service predicts the Pecan Nut Case bearer would be earlier this year. Based on the adapted PNC heat unity model, crop protection chemicals may be necessary around May 22-May 29. However, this may need to be revised aw weather may change as we progress. Also reported moth counts in pheromone traps will bring this to a more accurate prediction. Computer predictions are best used to plan when to set out pheromone traps, look for eggs and to plan insecticide application but are not reliable enough to be the only source of information to make application decisions. This year may prove this. Orchard scouting for eggs should begin two weeks before the predicted spray date as unusual weather conditions near the spray date, can either accelerate or delay egg-laying activity. I am getting reports of third generation larva in the shoots of new growth; these are from crop years 2014 and have managed to over winter to this spring. This is usual for this valley. Most Case bearer eggs are found at the tip of the nutlet, either on the top or hidden just under the tiny leaves at the tip of the nut let. A good hand lens is necessary to determine their development, (hatched, white, or pink). Also, look for bud feeding just below the nut cluster to detect the presence of newly hatched larvae. You should examine 10 nut clusters per tree. A cluster infested if it has a Case bearer egg or nut entry. If two or more clusters that are infested, insecticide applications may be necessary. Application should be two days after the eggs hatch. If no infested clusters are found, you should check again two days later. Keep checking until June 15. If by this date an infestation is not found insecticide application should not be required, for the first generation. Scouting for the seconded generation should start June 30 as currently predicted by the heat unit model. Caution is required when selection of a pesticide for backyard trees because of the great potential for spray drift onto nearby garden, pets, and living areas. Homeowner can only use products containing Carbaryl, and Malathion. Refer to label instructions for mixing and application rates and precautions. It is in violation of federal law to apply any chemical in any manner except what is on the label. Commercial orchards may use the above products or Interpid, Chlorpyrifos (Lordsban) (Cobalt), Confirm 2F, Pyrethroid or Spintor insecticide. Interpid is the product has a very good residual and is very effective and much safer than Oregano Phosphates and is the current product of choice. It does not harm predatory insects. This product is very safe for use around people. The fact it is not labeled for homeowner is a disappointment, because it is safer than some products, which is labeled for non-restricted use. Pecan nut Case bearer is one of the most important nut infesting insect pests of pecans. It is found in most the pecan growing areas from the east coast to Eddy County New Mexico. The Case bearer larva tunnels into nut lets shortly after pollination, often destroying all of the nut lets in the cluster. The most effective and reliable method of control is a well-timed insecticide application(s) made in the spring to kill hatching larvae before they tunnel into the nut lets. However, insecticides should only be applied if an infestations and nut load justify treatment. Subscribe to Eddy County Ag news at: http://nmsueddyag.blogspot.com/ Eddy County Extension Service, New Mexico State University is an equal opportunity/affirmative action employer and educator. All programs are available to everyone regardless of race, color, religion, sex, age, handicap, or national origin. New Mexico State University, U.S. Department of Agriculture, and the Eddy County Government Cooperating.