July 9, 2019

GDD update 7.8.19

Gorgeous day today – although sweat was dripping down my nose while I was digging plants this morning.  And collecting lily leaf beetle larvae. I live a charmed existence (really I do as I like all those things).


We are in that season where most of the eggs are laid, or larvae burrowing, or adults hiding from the heat.  The last few 1st generation pests are just about done and the 2nd generation hasn’t started for many yet.  Most insects – in NYS – only have one generation per year – thank heavens.  If you control them in the right window, you are done for the year. That can change as climates change unfortunately.


We have started looking at the insects we are catching in the habitat plots near our Christmas tree planting to see if we find pest, beneficials, or some that just wandered by.  We have 3 methods for catching insects – pan traps for flying insects, pitfall traps for soil insects, and sweep netting for those on the foliage.  Getting them all id’ed will be a chore but we are trying to have enough information to make some sense for our field day in September.   Lots of hover flies – a predator of aphids – in some plots.  Will that result in reduced balsam twig aphid?  We hope so.


Jason Dombroskie, who runs Cornell’s insect diagnostic lab, was helping (wow, is he good!).  I learned that white pine weevil is one of the adult insects that survives the longest.  John Freckleton can support that as he has white pine weevil traps and always tells me how many he has caught.


Things to look out for:


Japanese beetle adults will feed on leaders of fir and maybe other species.  1029-2154 GDD

They also lay eggs that become grubs that can feed on roots.  Japanese beetle traps are good at catching adults but the worry is that they pull them in but don’t catch them all.  If you use them, be careful where you put them.


Two spotted spider mites will start up again – 1300-2000 GDD

They like the heat.  And dust makes them happy.  Pesticides that kill off beneficial mites will sometimes result in a flush of the species we don’t want.  Also excess nitrogen makes them happy.


Pine needle scale 2nd generation is about to start – 1290-1917 GDD


The last few of the ones you’ve been watching:


Cryptomeria scale crawlers – 600-800 GDD

Elongate hemlock scale crawlers – 360-700 GDD

Bagworm – 650-750 GDD


Have a great week – and see you at Franke’s if you are going to the summer CTFANY meeting.


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.



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!


May 29, 2019

NEWA Update 5.29.19

Buds are breaking all around Ithaca and Geneva.  We’ll be going through our planting to see how they did over the winter.

Sorry for the long break – amazing how long it takes to catch up from a couple of days off!  Did you check NEWA because you were missing my email?

Everyone’s in the triple digits now – but the range from Canton to Riverhead is 140 – 488 GDD!

Not too much has changed overall.

We’ll add:

Elongate hemlock scale crawlers  360-700 GDD – remember the only sensible time to treat EHS (except dormant oil) is when the crawlers are out.

Two spotted spider mite – 363-618 GDD – look for trees with stippled needles (lots of tiny yellow spots) and bronzed interior needles and do a tap test.  Two spotted spider mites like it hot – and dry and dusty makes them happy so maybe not so far this year.


Here are the ones continuing:

Gypsy moth larvae hatching – 90-448 GDD – remember the small ones are the easiest to control with Bt.  And larvae can sent up silks to be carried by the wind, so treat trees around any that are infested.

Douglas fir needle midge adults –  200-400 GDD – traps are helpful to know when they start emerging from the soil

Pine needle scale – crawlers emerge 298-448


There is always something to scout for.  I hope you are catching up in the fields!


Have a great week!


May 20, 2019

GDD Update May 20, 2019

Well, this is different – sun and heat!  Based on the weather alerts popping up on my radio, some people got lots of rain this weekend, which continues to make everything difficult.

Most reports are ‘missed that window for weed/insect management, planting, etc…’.  Peter Brooks wondered what the effect of all the rain on GDD based insect models is.  I suspect the effect is less on their development and more on our ability to deal with them.  Now, for something that pupates or overwinters in the soil, there might be an effect.  Harder to escape muddy soils?

On the disease side, there is definitely an effect of a wet spring.  We’ve seen too much Phytophthora in the past to not know it is exacerbated by waterlogged soils.  And George Hudler is noted in the Branching Out newsletter for May 17 as saying that leaf, needle and rust diseases are expected to be at high levels in 2019.  He thinks Rhabdocline and Swiss needle cast are as high as he has seen in many years.  (I have heard comments about Rhabdocline this year after not hearing any for quite a while.)

So this is a year to make sure you get good coverage for your needlecast sprays.  Remember Brian has seen good results treating for the first time at 1.5 – 2 inch elongation of shoots for Swiss needlecast, later than the traditional recommendation.

Growing degree days for the farms I am following range from 85-345.  Where do you fall?  Find out at NEWA: http://newa.cornell.edu/index.php?page=degree-day-calculator


Things to be scouting for now or soon:

Douglas fir needle midge – adults emerge 200-400

Gypsy moth  – eggs hatch 90-448

Pine needle scale – first generation crawlers emerge 298-448

I don’t get many requests for information on sawflies, but if you have them (and there are several species), they may be emerging now (78-220 for European pine sawfly).  Treatment is usually spot treatment only and often only in the last few years before sale.  Unfortunately, Bt doesn’t work on sawflies.

Have a great week!