July 22, 2008
Remember the Golden Valley/ Wibaux Counties joint crop tour is on MONDAY JULY
28th. The Tour will start at 3pm at the SCD District Quarter east of Beach. Tour
stops include a Double Cropping Forage Trial, Alfalfa Variety Trials, Canola,
Soybeans and others. A steak supper will be provided for tour attendees, and is
sponsored by the Golden Valley SCD and Beach Co-op Grain. There will be a bus
provided to transport people from site to site. The bus and refreshments
provided during the tour are sponsored by the Wibaux Conservation District.
GET READY TO SCOUT FOR BANDED SUNFLOWER MOTH
Janet J. Knodel
Extension Entomologist
janet.knodel@ndsu.edu
Banded sunflower moth is just starting to emerge in our area. NDSU Extension
Entomology has had reports of high numbers of banded sunflower moth adults
caught in pheromone sentinel traps in extreme southern Manitoba just north of
Walhalla, ND. Fields should be monitored for adult moths and eggs when
sunflowers are in the R3 (immature bud elongated 0.5 to 2.0 cm above the nearest
leaf) stage.
Description: The adult has a dark band across the buff or yellowish-tan
forewings (see photograph). The wingspan is about 0.5 inch. Early instar larvae
are offwhite; late instar larvae are pinkish to red with a brown head capsule
(see photograph). Larvae will be about 0.4 to 0.5 inch at maturity.
Banded sunflower moth - adult and eggs (right side) Banded sunflower moth -
larva
Life Cycle: The adults emerge from local overwintering sites rather than
migrating long distances. In the northern states the banded moths begin to
emerge about mid-July and are present until mid-August. Adults tend to
congregate in field margins or adjacent crops during the day and then move into
the sunflower crop in the evening. Within a week after emergence they begin to
lay eggs on the outside of the flower bracts. Eggs hatch in 5 to 8 days and may
be found through early August. Larvae develop through five instars and are
present in sunflower heads from mid-July to mid-September. After feeding to
maturity, larvae drop to the ground to overwinter.
Damage: Newly hatched larvae move from the bracts (where they feed initially) to
the florets of the sunflower head and enter open florets to feed. During later
stages, the larvae tunnel through the bases of the florets into the seeds and
consume the contents. Each larva may destroy 5 to 7 seeds. Silken webbing on the
face of the head (see photograph) at maturity indicates the presence of larvae
within the head.
Scouting: Sampling plans have been developed using both adult and egg
counts. Adult moth and egg counts should be made when most of the plants are at
the R3 stage (see photograph). A low power magnifier is recommended for egg
counts. The new 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 details on adult moth and egg
scouting and economic thresholds go to Banded Sunflower Moth E-823 (Revised) -.
http://www.ag.ndsu.edu/pubs/plantsci/pests/e823w.htm
Sunflower at stage
R-3
Control: The economic threshold level has changed with the current high
market value. When monitoring for adults during daylight hours, one banded moth
per 100 plants is a reasonable threshold given the high 2008 sunflower market
prices. For egg counts, the threshold level in 2008 is about 2-3 eggs per six
bracts. Chemicals should be applied from the late bud stage (R4) to early bloom
(R5.1). Border spraying can be an option. Spraying in early morning or late
evening is preferred to minimize the impact of pollinators. Some common control
mistakes include: not scouting; waiting too long to spray; and perimeter
spraying only and not scouting the interior of the field.
REGIONAL MONITORING NETWORK FOR SUNFLOWER MOTH AND BANDED SUNFLOWER MOTH
Janet J. Knodel
Extension Entomologist
janet.knodel@ndsu.edu
Sunflower moth and banded sunflower moth traps are being monitored on a weekly
basis in the sunflower producing areas of the Great Plains from Texas to North
Dakota. Insect maps are being produced weekly to provide a general indication of
population levels in 2008. Please see the following websites for maps.
Sunflower moth: The pheromone trap catches for the male sunflower moth does
provide a reliable indicator of the economic populations (treatment levels) for
sunflowers in the R3-R5 crop stage. The current threshold is >28 moth per trap
per week. www.sunflowernsa.com/growers/default.asp?contentID=357
Banded sunflower moth: The pheromone trap catches for the male banded sunflower
moths is not a reliable way to determine treatment thresholds. Therefore,
pheromone trapping of banded sunflower moths should be used only to determine
whether moths are emerging and present in the area.
www.sunflowernsa.com/growers/default.asp?contentID=364
