can
remove them with a single application of a curative product like
trichlorfon (Dylox). In the fall, if you have white grubs in an area that
did not receive proper preventive grub control, you can also use
trichlorfon to rescue the area from grubs before predators such as rac-
coons and skunks tear up the turf to feed on the grubs.
It's a good practice to keep your preventive and curative grub con-
trol options clearly differentiated.
* Preventive grub control (imidacloprid). Apply in late May through
early August. Provides up to 4 months residual grub control (plus other
pests).
* Curative grub control (trichlorfon). Apply in spring or fall when
grubs are present in turf. Provides almost immediate curative control
(after being watered in) of all grubs present, but no residual control.
Trichlorfon should not be used at the same time that imidacloprid
is applied for preventive grub control. There are at least nine different
species of white grubs that occur throughout the United States, with
many or all species occurring in the same location. The timing for the
emergence, flying, mating and egg laying for each species is different.
If you apply trichlorfon on July 10, for example, you will control the
grubs present with this single treatment; however, Japanese beetle fe-
males can live for 8 weeks, mate multiple times and have multiple
clutches of eggs. Eggs deposited after a trichlorfon application will not
be controlled. Therefore, use trichlorfon when all the adult beetles are
gone
(fall and spring) and the only life stage present is grubs. That single
application, at the correct timing, controls the grubs where the appli-
cation is made. Preventive grub control treatments using imidacloprid
provide residual control of grubs, so if some eggs are deposited July 10,
they are controlled, and if another species deposits their eggs 10 days
later, they too are controlled. These are two very different control strate-
gies for two very different products used to control grubs.
Yes, the polar vortex was very cold. Yes, Minnesota might thaw out
sometime in mid-June this year. But don't sell your sprayers on eBay
or at the local garage sale: the insects will be back this year!
Ken Kukorowski is senior research scientist specializing in insecticides at
Bayer. He previously led the Bayer Advanced division's Product Innovation
Group. Prior to joining Bayer, Ken accumulated more than 20 years of industry
experience specializing in R&D and technical development, with a focus on in-
secticides. He earned a Bachelor of Science degree and a Master of Science degree
in Entomology from Michigan State University; and he earned a Ph.D. in En-
tomology from the University of Wisconsin-Madison.
Bayer, the Bayer Cross, Topchoice, Merit and Dylox are registered trademarks
of Bayer. Always read and follow label instructions. For additional information,
visit www.BayerCropScience.us.
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