Volume
5 Issue 10
July 22, 2008
Time to Scout for Banded Sunflower Moth
 Banded
sunflower moths have begun to emerge in the region and will require
field scouting to determine the populations present within fields.
The banded moth has been one of the more persistent sunflower insect
pests in the past ten years and was again responsible for seed
damage and many of last year’s insecticide treatments applied during
flowering (Figure
1).
 The
banded sunflower moth overwinters in the region in last years
fields. They pupate the next summer and emerge as moths in July (Figure
2). The larvae of the banded moth hatch from eggs laid on the
bracts of the flower bud. The larvae will feed on florets and seeds.
Moths are active in the region. A
network of pheromone traps in North Dakota, Manitoba, and NW
Minnesota began catching moths last week. To monitor the trapping
results, go to the National Sunflower Association web page at:
http://www.sunflowernsa.com/
Sampling plans have been
developed using both adult moth and egg counts. Adult moth and egg
counts should be made when most of the plants are at the stage R-3
(see
sunflower growth stages).
If you decide to look for eggs, a low power magnifier is recommended
for egg counts. The sampling system for adult moths should be
conducted during the day (late morning or early afternoon). The
moths remain quiet, resting on upper or lower surfaces of the leaves
of sunflower plants during the day. When disturbed, they flutter
from plant to plant.
For complete details on adult moth
and egg scouting and economic thresholds obtain the NDSU
publication, Banded Sunflower Moth E-823
(Revised 2006).
It can be downloaded from the web at:
http://www.ag.ndsu.edu/pubs/plantsci/pests/e823w.htm
The egg sampling and threshold will
require some review of the technique, which is provided in good
detail in the publication. The moth sampling is much easier, but may
have more room for error. Essentially, the moth sampling routine
would result in a recommendation to treat if only a single moth is
observed while inspecting 100 plants
(a set of 20
plants from 5 locations).
These thresholds can be adjusted for prices expected for sunflower
seed.
Timing of Treatments. The
best sunflower plant stage to treat is the R5.1 growth stage
(see
sunflower growth stages),
or
when pollen shed is just beginning. At this stage most banded
sunflower moth eggs have hatched and larvae are beginning to feed on
florets. Larvae will be exposed on the head and are susceptible to
the insecticide treatment. On older plants where the seeds have
formed, larvae begin feeding in the seeds or underneath the florets,
and are protected from the insecticide. By then, much of the feeding
damage already has occurred.
Table 1.
Insecticides labeled for Sunflower
head feeding insects.
Phillip Glogoza,
Extension Educator - Crops
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