The state of Maine
has secured a Section 18 “Crisis Exemption” registration for a higher rate of
Malathion 8Fl that is more effective for the SWD than the lower rate on the
existing label. This higher rate is in EFFECT on August 13 and only lasts for
15 days (August 13-28). If you decide to use this material at the higher rate
very strict reporting is required by the US EPA. The forms for reporting can be acquired from
the Maine Board of Pesticide Control.
Last week (Aug 10) spotted wing drosophila (SWD) showed up
in a few more blueberry fields. We have found adult male flies in traps in TWO
fields in Franklin (Hancock Co.), one field in Surrey, two fields in Ellsworth,
one field in Harrington, and one field in Jonesboro. I (Frank Drummond) have also
confirmed trapping of adult flies from several fields in Deblois (Washington
Co.). Thirty wild blueberry fields are being monitored by the Maine Dept. of
Agriculture and the University of Maine and many additional fields are being
monitored by growers and so far the picture is that SWD appears very spotty
across our blueberry growing areas. But, please be vigilant and continue to
trap for SWD in fields that you have not harvested yet.
What to do if you do
find flies? Well, there are several approaches, NONE of which are based
upon experimental evidence from wild blueberry research in Maine.
Conservative and
most safe approach: as soon as 1 fly is trapped and confirmed apply a
suitable insecticide at an interval that reflects the average persistance of
kill (residual in table) of the material (see list of insecticides below).
Liberal approach:
Coninue to trap after you catch your first fly and when fly numbers START to
increase from 1 fly in a trap to 3, 5, 10, etc., then consider applying an
insecticide.
Whatever strategy you pick, consider the following before
applying an insecticide:
1. If
you sell to a processor, check with them
to see what material can be used.
2. Make
sure that the PHI for the material that you choose is in accordance with your
harvest schedule.
3. A
PLANNED harvest 1-2 days after a confirmed trap capture may allow you to
harvest the crop withpout making an application if you feel that you can get
the berries out of the field immediately.
Currently
Available Products for SWD Control:
(Click here to enlarge table)
(Click here to enlarge table)
Chemical Class
|
Active Ingredient
|
Trade Name
|
PHI
|
Days of Residual
|
Comments
|
MRL for Canada (Yes/No)
|
Organophosphate
|
malathion
|
Malathion
|
1
|
5-7
|
Yes
|
|
phosmet
|
Imidan
|
3
|
7
|
Long
PHI
|
Yes
|
|
Pyrethroid
|
zeta-cypermethrin
|
Mustang-Max
|
1
|
7
|
No
|
|
bifenthrin
|
Brigade
|
1
|
7
|
No
|
||
zeta-cypermethrin+
bifenthrin
|
Hero
|
1
|
7
|
No
|
||
esfenvalerate
|
Asana
|
14
|
7
|
Very
long PHI
|
No
|
|
fenpropathrin
|
Danitol
|
3
|
7
|
Long
PHI
|
Yes
|
|
Carbamate
|
methomyl
|
Lannate
|
3
|
3-5
|
Short
lives, long PHI
|
Yes
|
carbaryl
|
Sevin
|
7
|
5-7
|
Long
PHI, Not as effective as others
|
Yes
|
|
Spinosyn
|
spinetoram
|
Delegate
|
3
|
7
|
Long
PHI
|
Yes
|
spinosad
|
Entrust
|
3
|
3-5
|
Short
lived, Long PHI
|
Yes
|
|
Pyrethrum
|
pyrethrum
|
Pyganic
|
0.5
|
2-3
|
Very
short lived
|
Yes
|
Posted by Frank Drummond
