We are in a drought in south Mississippi. Sure, some areas have had more rain, some less, but things are very dry overall. By my calculations (with data from Weather.com which may or may not be the most accurate) since June 1 we are 20.75 inches in deficit from the average in Poplarville.
Month AVG 2015 Deficit
June 5.3 in 0.88 in -4.42 in
July 6.4 in 1.35 in -5.05 in
August 5.4 in 0.93 in -4.47 in
Sept. 3.9 in 1.13 in -2.77 in
Oct. 4.1 in 0.06 in ????
So, as you can tell things are not good in terms of rainfall. Pecans, in particular, need a good bit of rain especially during the crucial time of nut filling. Which, as it turns out, is when the rain stopped falling this year. Un-irrigated orchards suffered tremendously, with many trees having no nuts at all and then eventually losing a massive amount of leaves, like the tree below.
Unfortunately this is a common sight around south Mississippi. I hear that things are a little better in central Mississippi and not bad in north Mississippi in terms of pecan production this year. Many trees have also tried to send out new growth to compensate for the lost leaves.
These new leaves and shoots have a high probability of being damaged by cold weather when it finally comes for good. This new growth will not have time to properly harden off for the winter. Defoliation can lead to poor return bloom next year as well as overall tree stress which can affect yields and fruit quality.
If your tree is in this shape what can you do? If you have the capacity to water the tree do so. If not, then there is nothing to do but hope for more rain.