June 25, 2019

GDD update 6.25.19

Getting close to breaking the 1000 mark in some areas (sorry Canton and Williamson) and this week may be the first week of all 80’s in Ithaca so far.

 

What’s in a name? We all get used to using common names but sometimes they are confusing.  Bagworms and tent caterpillars aren’t the same thing although they do both make habitats for themselves.  And sometime the management is different. Even within a group telling them apart is hard.  Here’s a comparison of tent caterpillars and Gypsy moth larvae: https://www.dec.ny.gov/animals/7436.html

 

I don’t think of tent caterpillars as Christmas tree pests.  Ever seen them on your trees?  Bagworm could be but I hear more about that in landscapes.  Gypsy moth?  Yes! I think that’s what ‘those little black worms’ the caller was asking about probably are.

 

In case you have them – bagworm larvae emerge from their bags at 650-750 GDD. And Gypsy moths are getting ready to pupate in some areas (around 450 GDD) – so no more management methods will work.

 

I learned many things from Rich Cowles at the Dutchess County Twilight (nice to see some of you there, too).  Scale crawlers that stay under the female covering are hard to smother with dormant oil because there is an air space for them.  Makes sense (and I am an insect geek!).

 

Keeping weeds down makes it easier to scout for elongate hemlock scale as they start on the lower inner branches and move up.

 

Continue scouting for these:

 

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

 

 

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!

 

June 6, 2019

NEWA Update 6.6.19

What’s new?

Weir’s cushion rust was sporulating in Orange County in the end of May, I learned from Branching Out.  It’s a disease of spruce – we don’t have exact GDD for diseases since environment is so important.  More information at: http://plantclinic.cornell.edu/factsheets/chrysomyxaweirii.pdf

 

For those areas moving into the 600’s in GDD, Cryptomeria scale crawlers will becoming out (600-800).  They are sometimes hard to tell from elongate hemlock scale  – whose crawlers come out earlier 360-700.  It is important to know which one you have so you apply pesticides when they will work.  https://extension.psu.edu/elongate-hemlock-scales https://extension.psu.edu/cryptomeria-scale

 

I’ve been reading pesticide labels – definitely not for fun!  I’m sure you have been frustrated with them.  The pest and the crop must both be on the label and looking at several Chlorothanlonil labels – they were all different!  Argggh!  If you have questions, I know who to ask at the Pesticide Management and Education Program.

 

Continuing –

Two spotted spider mite – 363-618 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

European pine sawfly larvae – 78-200

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

Zimmerman pine moth larvae– 121-246

 

The sun is out!  Hurray!

 

Have a great week!