What Happened To My Pecans?

Press Release Eddy County Cooperative Extension Service 1304 West Stevens Carlsbad, NM 88220 For More Information, Contact: Woods Houghton, Eddy County Agriculture Agent Eddy County Cooperative Extension Service Phone: 575-887-6595 Fax: 575-887-3795 whoughto@nmsu.edu FOR IMMEDIATE RELEASE What Happened To My Pecans? Although fall can be a rare season weatherwise in Eddy County New Mexico, it is a season of great anticipation for pecan growers whether they have one tree or several thousand. Those of us who cherish such nuts know that the taste of that first fresh nut of the season (properly dried of course) is something to behold. However, many times the crop is lost long before we can ever harvest a single nut. The pecan is a most unique horticultural crop in that it stays on the tree from May until October and sometimes December?? 6 months ?? half a year ?? that's a long time! Another interesting characteristic is how the nut develops, that is, the nut is full sized by the end of July with absolutely no kernel inside. Hence, if growing conditions are favorable early in the season, one will have large pecans ?? then, if it turns dry later ?? the nuts will be poorly filled. So, although there are years when trees have super good nuts regardless of what we do, there are a lot more factors involved in production than meets the eye. Premature nut drop in summer may have been caused by a lack of pollination, insect damage and/or stress. Pecans require cross pollination, but with all the pecan trees around, it is rare for there to be a lack of pollen. However, unfavorable environmental conditions such as heavy rain or hot dry winds during bloom could cause pollination problems and result in nut drop when the nuts are small. Another common cause of early drop is insect damage. The first generation pecan nut casebearer can cause a lot of drop. Nuts with such damage will be characterized by an exit hole covered by frazz. There can be as many as three generations a year. Usually the first generation causes the most damage, but this can vary from year to year. Other insect feeding on the nuts before shell hardening will also cause the nuts to drop. Insect puncture by stink bugs will cause interior nut discoloration and later drop. Nuts which drop with no interior discoloration is caused by physiological drop or stress, that is, not enough water or too much. However, once the nut shell becomes hard ?? the nut will no longer drop from stress, rather the leaves drop resulting in little to no filling of the nuts. Poor shuck opening can be caused by either, third generation casebearer damage and/or stress. A common late season problem in many locations is casebearer. Such nuts will have black lesions which can be spongy. When one cuts into the lesion, one will find a small white larva or worm tunneling in the shuck. Early damage will cause shucks not to open and later damage causes poorly filled nuts. If the first generation is controlled this is usually not an issue. Excessive feeding by stink bugs will also cause nuts not to open. A similar shuck problem where the shucks will not open can be caused by stress. There are no apparent insect problems in the shuck and the kernel is usually shriveled. Such "stick?tights" are caused by drought and heat stress in September and October. Pecans require water right up until the time of shuck split to reduce this problem. Nuts sprouting in the shuck before harvest (vivipary) are also reduced by late season water and/or stress reduction. I have gotten some brought in this year mostly of different varieties than Western or Wichita. The problem seem to be in a few Burkerts, Pawnee, and Mohawk. A similar shuck problem where the shucks will not open can be caused by stress. There are no apparent insect problems in the shuck and the kernel is usually shriveled. Such "stick?tights" are caused by drought and heat stress in September and October. Pecans require water right up until the time of shuck split to reduce this problem. Nuts sprouting in the shuck before harvest (vivipary) are also reduced by late season water and/or stress reduction. Black spots on the kernels are caused by stink bugs feeding on the nuts after the shell hardened. The black spots on the kernels are bitter and inedible and can be severe in some years. However, the damage is undetected until the nuts are shelled. Such nuts can be salvaged by breaking off the spot if minor. Another common problem found at shelling is fuzz on the surface of the kernels. This fuzz is typically caused by stress such as drought. It is a very common problem on trees with too many pecans. Also nuts maturing on broken limbs generally have a lot of fuzz. So, when one asks the question: What happened to my pecans, the answer is usually not simple. Rather it is a combination of factors which caused the problem or problems. Poorly filled kernels can be caused by all of the following: crowded trees, overloaded tress, shallow soil, late summer drought stress, casebearer damage, stink bug damage, oversized nuts and poor nutrition. Thus, one can understand what a tremendous challenge pecan production can be for the commercial producers to produce quality nuts year in and out. Also, the price you have to pay for quality kernels should not seem unreasonable. 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.