June 14, 2019

GDD update 6.14.19

Inching up there – although today probably isn’t adding much!

Things to be looking for:

‘Shepherd’s crook’ wilted leaders on spruce, pine, Doug fir – occasionally fir – are caused by white pine weevil.  Cut them out and destroy the leaders before July (even this year!) to prevent adults emerging.  Prune down to healthy green wood.

Another note on white pine weevil – 2-5% of trees damaged this season is the threshold (in forestry) for treating next season.

Hey, they don’t read the books! Spruce spider mite should be a cool season mite but according to Branching Out they are being found in high numbers even in warmer seasons, so keep scouting if you’ve had them before – especially spruce.  Tap tests – and when you smear them on paper, they leave a green streak (from all the chlorophyll they have been sucking out of your plants)

 

And keep scouting for cryptomeria scale even after 700 GDD.  Spray recommendations from PA suggest continuing management beyond that point if you find crawlers.

 

Continuing:

Two spotted spider mite – 363-618 GDD

Cryptomeria scale crawlers – 600-800 GDD

Elongate hemlock scale crawlers – 360-700 GDD

Gypsy moth larvae – 90-448 GDD

Douglas fir needle midge adults –  200-400 GDD

Pine needle scale crawlers – 298-448

Striped pine needle scale crawlers – 400-500

Introduced and red-headed pine sawfly larvae – 400-600

 

Have a great week!