Pecan Stick Tights

WHY DO I HAVE STICK TIGHT WITH MY PECANS?

Each pecan season is different; a friend of mine told me he had been farming in Eddy County for more the 60 years and that it would be easier if there was two years the same so he would know what to do.  This year is not the same as any other year except I have received calls from all over Eddy, Lea and Chaves counties asking about pecans still in the shuck or stick tights and it is all the nuts on the whole tree. In the other articles I’ve written on this subject is was not all the nuts on a tree and when you cut open the nuts that were stick tight they were less mature and not as filled as the non-stick tight nuts on the same tree.   This year is different because the black shriveled shuck is around every nut on the tree and when you cut them open they are filled and fairly mature.  The varieties that mature earlier, like Pawnee are open and dropping nuts and later maturing varieties are having stick tights.  That is my observation in my orchard and I have a number of varieties that are all fertilized and watered the same.   The shuck split occurs with the production of ethylene, which is the same natural chemical that turns tomatoes and chilis red and bananas brown. I have taken a few pecans and put them in a paper sack with a few green bananas and in a few days the shucks open up.  Pecan produces ethylene when the nuts are completely filled in the kernels as the nuts mature. However, as I said every year is different.  Reading articles in Pecan South and Georgia Pecan there is a lot we just don’t understand yet in pecan physiology, but we are working on it.   Dr. Heerema and New Mexico State University Plant Pathology has recently confirmed bacterial leaf scorch in pecans and this has been associated with stick tights because of reduced water movement in pecans.  There are numerous articles on drought induced pecan stick tights.   

If the nuts are filled and shuck still stick tight you may have 2^nd or 3^rd pecan nut case bearer larva between the shuck and the nut.  As they feed they cut the pipes that deliver nutrients to the shuck and nut.  This prevents the water pressure from opening the shuck or interferes with the production of ethylene. 

If there are lots of black on the shuck and on the nut shell this can be from the case bearer or more than likely from stink bug damage.   Again this is a result of broken pipes and loss of pressure to open the shuck or some interference in the production of ethylene. 

Then there is stick tights that occur when under hot dry wind in late July early August during the water filling stage of the nut, trees do not receive enough water to fill the nut.  Often stick tights are associated with an “on” year when there are lots of nuts and therefore lots of demand for water.    Physiological drought in pecans can occur even when the producer applies sufficient water to the soil.   So if as a home owner you put your pecan in a bag with bananas and they still do not open, it was one of those other causes, and what was the cause this year; but may not be there next year.   This year my personal thought as a grower, because it is so wide spread in the valley and early maturing varieties that have a much lower occurrence in this weather.  This year we had an early hard freeze. We normally get a light freeze 30-32 F the first week of November but this year we had a hard killing freeze below 28F the first week of November, which breaks the pipes as the insects do and breaks cell walls so ethylene is released or not produced.  As we know a number of things can cause or work together to create similar symptoms.  This is my thought on the stick tights this year, which is different from what I had for last year.    Dr. Heerema told me, “At this point though, I’m still hopeful that as the shucks dry down they still might pop open.  One grower I talked with on Friday said that exactly that was happening.”     

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