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Put out 1-2 stakes per field, one on each side, just barely within the
field edges. Have them face the prevailing wing direction. A
good place to place the stakes is next to last years beet field as the
flies will likely be moving in from there to the current fields.
Sticky trap count for Sugar Beet Root Maggot Fly-- 15-20
flies per day, or when you get to 50-60 flies total.
Flies normally appear when the temperatures get to over
80 degrees consistently, or when 300 - 600 GDDs
have been reached (using a base of 40).
Normally the flies do not appear until the 2nd week of
May, and may become serious from the 3rd week of May through the first
week of June.
A one pint/acre broadcast rate will have activity on the adult
flies. A one to three day residual is all that can be expected and
will vary with the weather.
Banding one pint/acre in a 7 inch band or 2 pints/acre
broadcast has given the best results. At these rates, Lorsban can
have activity on both the flies and the maggots as they hatch.
A 1/4 inch rainfall within 24 hours is the ideal after
application to put Lorsban where the eggs will hatch. A rotary hoe
or harrow can also be used to "create a granular effect at the soil
surface" and again places the Lorsban where the eggs will hatch.
best time to spray is late inthe day if possible. Second best is
early morning when there is dew on the plants. 10:00AM - 4:00PM is
the worst time. The direct sunlight on the beets warms up the
emulsifier in the Lorsban and there may be some spotting on the
leaves. If spraying must be done during the day, then use more
water, 10GPAby ground and 5GPAby air will help dilute the effect on the
beets.
With Betanix and Betamix herbicides, a 3 day delay
between Lorsban applications is required for best crop safety. At
this time Dow AgriSciences does not recommend Lorsban applied with Upbeet
for crop safety reasons.
Lorsban applied with grass herbicides is okay- use 1/2
the normal rate of crop oil or MSO with these. Avoid spraying during
the heat of the day if possible, or use more water. Re-entry
interval for Lorsban 4E is 12 hours.
If you have additional questions, please contact your local
agricultural staff.
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