Q. I
have several pecan tree and some of the nuts I cracked this year have black
spots on the nut and others have a soft brown film on part of the back of the
nuts. What caused these problems and what can I do to prevent it.? The pecans
have been producing for 30 years and I
have never had the problem until last year.
have several pecan tree and some of the nuts I cracked this year have black
spots on the nut and others have a soft brown film on part of the back of the
nuts. What caused these problems and what can I do to prevent it.? The pecans
have been producing for 30 years and I
have never had the problem until last year.
A. I am
guessing that these black spots are on the meat or seed that you normally eat.
I am also guessing that when you eat this pecan meat that it is bitter. If you
are moving your head up and down in agreement then this is insect feeding
damage by one of the stink bugs.
guessing that these black spots are on the meat or seed that you normally eat.
I am also guessing that when you eat this pecan meat that it is bitter. If you
are moving your head up and down in agreement then this is insect feeding
damage by one of the stink bugs.
We
do have stink bugs in Las Vegas but one particular type of stink bug or a close
relative is the leaf footed plant bug which also damages pomegranates,
pistachios and almonds.
do have stink bugs in Las Vegas but one particular type of stink bug or a close
relative is the leaf footed plant bug which also damages pomegranates,
pistachios and almonds.
 |
| Closeup of leaffooted plant bug. Photo contributed by Bill Stillman. |
This
feeding damage can cause the entire nut to drop off the tree or can cause these
black spots to appear on the meat. To eliminate this kind of damage you would
have to spray the entire tree with an appropriate insecticide.
feeding damage can cause the entire nut to drop off the tree or can cause these
black spots to appear on the meat. To eliminate this kind of damage you would
have to spray the entire tree with an appropriate insecticide.
You
would have to start early because they will begin building their population on
the tree as early as April. These insects also feed on tree leaves, vegetables
and all of our major fruit trees. They overwinter on ornamental plants that
remain evergreen in our landscapes.
The
adults have wings so they can fly from neighbor to neighbor. Soap and water
sprays will kill these insects if they are sprayed directly with this
concoction. Soap and water sprays have no residual so no poison remains when it
dries. This can be an advantage and disadvantage.
Other
sprays are fruit and nut sprays that contain synthetic pyrethrins or
pyrethroids. These will also work but the main problem you will have is getting
the spray to cover the large tree from head to toe. These black spots can be
broken off of the nuts and the nuts can be eaten with no problem.
sprays are fruit and nut sprays that contain synthetic pyrethrins or
pyrethroids. These will also work but the main problem you will have is getting
the spray to cover the large tree from head to toe. These black spots can be
broken off of the nuts and the nuts can be eaten with no problem.