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Management Updates: Apr 15, 2016

Wacky Weevil Weather
Apr 15, 2016

Many people have been asking what the situation is with the annual bluegrass weevil. As you know, we had some warm weather a couple weeks ago, which pushed some of the flowering plants along, and certainly there were a few weevils "out and about". But in general, the sense is that the weevil captures in linear pitfall traps has been relatively low so far. We are beginning to see weevils on the fairways, but remember that those adults are still reproductively immature.

The degree day accumulation for 2016 was similar to 2012 early in April, but has slowed considerably. At this time (15 April) the cumulative degree days appear to be right between the crazy hot years (2010 and 2012) and the cooler years (2009, 2011). My guess is that the phenological indicators (the usual Forsythia "half green - half gold) will be our best indicator for timing any adulticides. One thing that is noticeable this year is that Forsythia bloom appears to be much sparser than in previous years. Many of the blossoms that had opened before the severe cold of last week may have been damaged. Certainly we saw that most of the star magnolia blossoms died as a result of that hard freeze. So we may be tricked into thinking that Forsythia hasn't reach full bloom, and might not notice that the green leaves are starting to bud.

With the forecast for warmer temperatures over the week-end, start watching for signs of green on the Forsythia. But hold off on your applications until we reach "half green - half gold".

Submitted by: Dr. Pat Vittum