[Arid_gardener] Pecan problems

[Tyler Storey]

Gerald, good morning,
Your pecan tree is just fine; it's the exceptionally late warm weather we
had this fall that caused the problems you're seeing.  My pecan did the same
this year.  
First, the germinating seeds.  The long story involves a hormone called
abscisic acid that prevents seed germination, among other things.  The short
version is that the warm weather prevented the seeds from falling from their
husks, and the combination of warm weather and rain caused them to skip
their normal dormancy and start to sprout.  There is nothing you can do to
prevent this from happening.
Next, the sticky stuff.  What that stick, shiny, and sweet-tasting stuff is,
is aphid excreta, also known as honeydew or insect poop.  In the fall,
aphids reproduce rapidly on the underside of pecan tree leaves, sucking sap
from the leaves and excreting honeydew out their other end.  Because the
weather stayed warm longer, the aphids were on the tree longer and had more
time to eat and excrete.  Because we had no early rain to wash it away, the
honeydew built up in a layer much thicker than we normally see.  You might
have noticed honeybees buzzing around the tree and stopping now and again to
scoop up some of the stuff; it's very sweet.
On my pecan this year, I noticed an explosion of lady bug larvae.  They look
like little tiny yellow and black striped, or yellow and orange striped,
Gila Monsters.  The abundant supply of their favorite food -- aphids --
caused a great increase in lady bugs as well.  
You might also have noticed an abundance of ants in your tree.  This is
because the ants eat the honeydew, and are known to "farm" the aphids,
moving them about to fresh leaves.
Your options for controlling the honeydew buildup are limited; you don't
want to use any kind of insect spray for several reasons: 1) it's a food
crop and you could poison yourself; 2) pecan trees are large and hard to
spray carefully and you could poison your entire neighborhood; 3) you don't
want to poison the ladybugs; and 4) sprays aren't very effective on aphids
anyway.
Because the aphids are moved about by ants, you can try a tanglefoot band on
the trunk to prevent the ants from climbing; I have done this and it seemed
to help greatly.  You can use the spray attachment on your hose to rinse off
the aphids and cut through the honeydew with water; this will help a bit.
Or, you can just go out and watch the little tiny Gila Monsters catch and
eat the aphids while the bees buzz around.  It's like a National Geographic
Special on a very tiny scale.  
Hope this helps,
Tyler

tyler at tylerstorey.com
http://tylerstorey.com
602-738-2978

-----Original Message-----
From: arid_gardener-bounces at CALS.arizona.edu
[mailto:arid_gardener-bounces at CALS.arizona.edu] On Behalf Of
jerry.mead at cox.net
Sent: Saturday, December 29, 2007 10:19 AM
To: arid_gardener at Ag.arizona.edu
Subject: [Arid_gardener] Question from Home-Hort WWW page

Gerald Mead
85028
jerry.mead at cox.net

I have a Pecan tree that is maybe 18 yrs. old.  I believe it is sufficently
watered, have applied zinc & fertilizer each year.  It has provided
sufficient nuts in past years, butthis year the nuts have stayed on the tree
longer than ever, and the nuts are germinating in the husk, resulting in a
nasty tasting pecan.  This fall it developed a sticky substance on the
leaves, which it does every year, but it lasted much longer than normal.
Would like to hear what may be the problem.


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