GDD update for May 8, 2019

One thing I was reminded of this week – things can change quickly!  Especially when you get busy!

Monday I was out in our beneficial habitat plots setting up pitfall traps and helping with sweep netting.  We are certainly catching bugs – especially where there are flowers, and even weeds count (oh, yes, we have weeds).  We can’t identify them all yet but there are definitely beneficials out there already.  We caught several pink spotted ladybeetles – an excellent aphid parasite that you want if you have balsam twig aphid.

Why am I telling you this? Not just so you can be happy I spent a day away from my desk (Yes!) but because it suggests 2 things:

  • Flowering plants – beneficial habitat plots or weeds (if they aren’t interfering with production practices) – will draw the good guys in to your plots where they will feed on the pests you don’t want.
  • If you are applying pesticides, knowing the effects on beneficials will help you avoid killing them off.  This information isn’t that easy to find but if you want to know what I can find on a particular pesticide, send me a note and I will do my best (and include the information in these notes).

A quick review of where most people are:

Balsam twig aphid eggs will be hatching for many of you (30-100 GDD) and the best control is between egg hatch and bud break.

Balsam woolly adelgid treatment is before bud break (no GDD available).

Cooley spruce gall adelgid nymphs on Douglas fir or spruce are still in a treatable stage for some locations (22-91 GDD)

Douglas fir needle midge adults will be emerging from the soil (200-400) soon and heading out to lay eggs on your trees.  Yellow sticky cards will tell you exactly when.

Elongate hemlock scale adults can still be controlled if your trees are still dormant (7-120) but no-one is yet at the stage of treating crawlers (360-700)

Gypsy moth larvae will be hatching (90-448 GDD) and the Bt applications work best on small larvae.

Pales weevil and Eastern pine weevil treatment still possible for some (7-121 GDD and 7-100 GDD respectively)

Pine needle scale eggs should be scouted  (98-248 GDD) but I wouldn’t expect crawlers to be out for anyone quite yet (248-448)

Spruce spider mite eggs should be hatching – or already done (50-121 GDD)

White pine weevil – getting close to the end for everyone if you aren’t already there (7-58 GDD).  The next step is to cut out the shepherd’s crooks caused by the larval feeding.

Zimmerman pine moth – does anyone see this? – larvae are hatching now for some of you (121-246 GDD)

Does anyone get sawflies or pine bark adelgid?  As there are fewer pines grown as Christmas, we see fewer pine pests.  But they are still in the landscape trade.

A long one today since you got off easy last week!


Have a great week!