1. At the risk of stinkbug overload after previous coverage of this
topic, there is one more feature of these insects that I think is worth
mentioning. Unlike any other insect I have seen, the stinkbug is
capable of penetrating the plastic sandwich bags that many of us use for
protecting apples.
2. Apparently, the brown marmorated stinkbug has a feeding tube that is
long and sharp enough to puncture plastic and continue on into the flesh
of apples. The result is to alter and discolor the cells of the apple
down to a depth of one-half inch or more below the skin. Damage is
usually so extensive, that ripe apples are rendered practically useless
for anything but cider. Certainly they would not be marketable,
although the home grower can cut off much of the apple and still wind up
with something to eat. The condition under the skin resembles what I
have always (perhaps mistakenly) called corky spot. I have always
believed this was caused by calcium deficiency, but it may have been
stinkbugs all along.
3. Because the 2010 season was the first that I have noticed such an
infestation of these insects (though they may have been present in
smaller numbers before), and even though I knew they were present on the
trees, I never saw one in an apple bag and was confident the bags would
protect the apples just as they do from other insects. The stinkbug
seems to be a warm-weather insect, and didn't really get going until
August into September here. Earlier apple varieties like Yellow
Transparent escaped damage completely, but the midseason and later
apples were devastated. No problems were observed on peaches, plums or
apricots, most of which are down before mid-August. The best and most
beautiful of the apples, such as Goldrush, Fuji, Pink Lady, Ashmead's,
Albemarle Pippin, Blushing Golden, etc. were practically ruined.
Meanwhile, the stinkbugs were also attacking crops like tomatoes and
peppers, leaving telltale areas of white cells beneath the skin. It
seems that as soon as sugar begins to show up in a fruit or vegetable,
and the weather is warm, the stinkbug is waiting.
4. I am preparing apple bags for this season now, but I am clearly
going to have to take additional measures to keep this from happening
again. Permethrin seems to knock down the stinkbug pretty well,
although it seems hard to kill with other insecticides. I am prepared
to spray the trees with bagged apples, but this strategy will work only
if an insecticide has a residual effect on the stinkbug. I seem to
recall that Alan had observed little residual effect in his efforts to
control this insect. If he is right, as he frequently is, I really
don't what I would do next. Until USDA or someone comes up with a
solution to this infestation, I will be experimenting and looking for an
insecticide that would give me some extended protection without having
to spray 2-3 times a week.
5. We have watched stinkbugs emerge around the house, greenhouse, and
even garage all winter long on sunny days, so they are certainly not
gone. I don't understand their life cycle or reproductive habits well
enough to know the signs of trouble for next season. Certainly, this
stinkbug is different, and far more numerous and aggressive than others
of this species that I have seen before.
6. As a hobby grower, this is not an issue that affects my livelihood,
but I surely sympathize with the commercial growers that still survive
in the MD/VA area and along the east coast. Not to mention Alan Haigh,
whose business is fruit tree care.
Don Yellman, Great Falls, VA
[NAFEX] Stinkbugs Defeat Apple Bags,
Don Yellman, 03/31/2011