Winter Grain Mite

Winter Grain Mite

Winter Grain Mite

Winter grain mites are showing up in wheat in the very northern sections of Grant County.  Under “normal” conditions it takes so many mites to even begin to threaten wheat that they are not something we worry about. “Usually” it is so many that when trying to observe them you are unwilling to kneel down, let alone lay down, for fear of being consumed or at the very least shedding all your clothes as you left the field.  The ground is moving.

They are extremely small, about the size of this period (.) with orange legs and a black or dark bluish body.  (See picture)

Economic thresholds are not really established but estimated at 200 or so per plant, some data shows 200 per foot of row.  Usually they are not of any concern until the wheat field starts to have a silverish gray cast to it.  Under most weather patterns wheat can outgrow most mite stress and can recover without yield loss with adequate moisture especially as the days elongate and the plant starts growing.

The fields I have observed this winter with mite presence were not at those population levels at the time of day I was looking, and the fields did not have that cast to them.  However with the drought we are experiencing the plant is already stressed and probably cannot take as many other troubles.

Controlling mites with an insecticide can often be frustrating due to their lack of size and the dry conditions that they proliferate in. However, if one has a considerable mite presence, and is going to go over the wheat acres anyway to top-dress a herbicide, then it might be good management to include an insecticide such as Lorsban (or a generic), or Dimethoate with that tank mix.   



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