Stink Bugs Offending Arkansas Blackberries
by Aaron Cato - July 8, 2022
Stink bugs are out of control in most blackberry plantings around the state. See below
for information about how they cause losses and what growers should do about them.
Stink bugs are often brought up in relation to blackberry, but I would argue that
I’ve rarely stepped into a commercial planting that warranted an insecticide application.
So far this year every single field I’ve been to needed to be sprayed for stink bugs.
I’ve also yet to get a blackberry call this year where a grower or an agent didn’t
bring up all the stink bugs they’ve been seeing. Stink bugs don’t actually physically
cause damage to the berries, but they definitely can run afoul of your customers and
their willingness to come back for more berries.
See below for information regarding how stink bugs can effect a grower’s bottom line,
when control is necessary, and how to get rid of them. Also check out the 2022 Caneberry Spray guide for more information about blackberry pests.
Stink Bugs and Blackberry Stink bugs are commonly found in blackberry and don’t usually cause too much of a
stink. They do feed on blackberries as seen in the picture below (Picture 1) , but they aren’t after the tasty drupelets like you and me. Dr. Doug Pfeiffer at
Virginia Tech University demonstrated that stink bugs are actually feeding on the
receptacle of the berry, which is the white portion of the berry structure behind
the drupelets. Stink bugs will pierce a drupelet every now and again trying to get
to the receptacle, but that usually isn’t enough to make the berries unmarketable
in local markets. Its not uncommon to find several different species of stink bug
feeding on blackberry such as the adult green stink bug (Chinavia hilaris ) in picture 1 , or the immature green stink bugs shown in picture 2 and 3 . We also commonly see brown stink bugs (Euchistus servus ), brown marmorated stink bug (Halymorpha halys ), and many leaf footed bug species.
Picture 1 – Adult green stink bug (Chinavia hilaris ) feeding on a ripe blackberry.
Picture 2 – Immature green stink bug (Chinavia hilaris ) feeding on an unripe blackberry.
The problem with Stink Bugs It’s not hard to find drupelets that have been pierced by stinkbugs but that usually
isn’t too big of a worry. The real issue is that stinkbugs will readily release a
foul-smelling defensive chemical when startled, which will in turn foul the fruit.
Fouled fruit taste just exactly as stink bugs smell, which is not a pleasant experience.
I think everyone reading this who has been unlucky enough to eat one probably remembers
it. Sadly, I have eaten enough stink bug-fouled berries this year to almost keep me
from trying anymore.
The main issue that growers face from large populations of stink bugs is an increased
chance that consumers may have a bad experience. The risk of eating fouled berries
increases at high populations as stink bugs are startled by pickers or others working
in plantings, and also because stink bugs potentially become more easily agitated
when they run afoul of each other often. We’ve seen this in many places this year
where you can hear bugs buzzing each other and often can already smell them in that
area. One thing to note is that leaf-footed bugs do not foul berries and are therefore
not a worry for growers.
Picture 3 – Immature green stink bugs (Chinavia hilaris ) feeding on unripe blackberry.
How to Manage Stink Bugs in Blackberry In a normal year we tell growers to keep on the lookout for stinkbug egg masses, hatched
out immatures as seen in picture 3 , and a large amount of adults. Currently a threshold doesn’t exist for stink bugs
and it can be hard to gauge what number translates to consumers eating foul berries.
In normal years we see stink bugs very infrequently, maybe 1-2 adults every 50 plants
or so and don’t seem to encounter fouled berries. We normally begin to find issues
when we are seeing stink bugs every few plants or seeing a lot of hatched out immatures
like in Picture 3 .
Controlling stink bugs should be fairly simple for blackberry growers. Although we
wouldn’t normally recommend automatic insecticide applications (especially for stink
bug), in blackberry they are necessary for spotted-wing drosophila. The advantageous
part of this schedule is that many insecticides that work for spotted-wing also do
a pretty good job with stink bugs. Currently growers are utilizing chemistries including
pyrethroids, organophosphates (Malathion), diamides (Exirel), spinetorams (Delegate),
and spinosads (Entrust) for spotted-wing management. Of those insecticide chemistries
listed, growers should only expect reasonable control from pyrethroids which includes
Brigade (bifenthrin), Danitol (Fenpropathrin), and Mustang Maxx (zeta-cypermethrin).
Mustang Maxx is most commonly used when blackberries are ripe due to the PHI only
being 1-day, while Brigade and Danitol both have a 3-day PHI.
We currently recommend growers use Brigade (bifenthrin) to clean up stink bugs if
they are observed at high levels pre-harvest, like was observed in picture 3 . If harvest has already started, growers will need to rotate back to a pyrethroid
in their spotted-wing spray schedule when stink bug controls becomes necessary. Growers
that have rotated back to Mustang Maxx in their schedule will see a marked reduction
in stink bug numbers, but keep an eye out for populations that are bouncing back.
