September 27, 2019

GDD update 9.27.19

Trying to get back on schedule – whatever that means!

 

We had some potentially exciting weather last night at the Beneficial Habitat Twilight meeting last night but most of it missed us!  It was nice to see some of you there!

 

We got a different viewpoint on some possible benefits of even those insects we consider pests from Jason Dombroskie, Cornell’s Insect Diagnostician – who has met few insects he didn’t like in some way.  That benefit might just be that they are food for insects that help control other insects.  We are learning a lot about what types of beneficial insects are in our habitat plots that might help control pests as we evaluate our samples.  Lots of ground beetles and hover flies.

 

And some good news on spotted lanternfly.  Some areas may not have sufficient GDD to allow completion of the life cycle.  Penn State is studying it now.  Hurray for GDD!

 

One of the things Maria van Dyke talked about last night is the Pesticide Decision-Making Guide to Protect Pollinators in Landscape, Ornamental and Turf Management.  It is available at the NYS IPM website at https://pollinator.cals.cornell.edu/sites/pollinator.cals.cornell.edu/files/shared/documents/Pesticide%20Decision%20Making%20Guide%20for%20Landscape,%20Ornamental%20and%20Turf%20Management_022619.pdf

 

And Amara Dunn did a great job of walking everyone through the plots.   You can live somewhat vicariously by checking out her blog Biocontrol Bytes. https://blogs.cornell.edu/biocontrolbytes/?s=habitat

(you can read all the posts if you take off the ?s=habitat at the end of the url)

And what should you be scouting?

Spruce spider mite – 2375- 2806 GDD

Doug fir needle midge – remove heavily infested trees (carefully so you don’t spread the pest) before larvae exit the needles (needles will turn brown). Mark infested trees for placing traps in the spring

Elongate hemlock scale – keep scouting for crawlers.

Cryptomeria scale crawlers – 1750-2130 GDD

Japanese beetle adults – 1029-2154 GDD

 

 

Wading River and Riverhead LIHREC have more GDD than anything on the list – but I think you might still do some scouting, just in case the insects don’t read the books.

Have a great week!

September 13, 2019

GDD update 9.12.19

Another cool day before more heat – and some of the growing degree day curves are starting to show a little slowing in increase.  And that means it is a good time to scout for spruce spider mite.  Tap some branches over a white paper plate and if something runs, smoosh it.  If it is small and leaves a dark green smear, it is probably a spruce spider mite (really scientific, right?).  While two spotted spider mites like it hot and dry, spruce spider mite likes it cool.  So even if you aren’t in the right GDD range, take a look.  The damage doesn’t disappear so sometimes interior bronzing is your clue, but it’s better to find them before you see that much damage.

 

You might see predatory mites, too.  Very small and fast and sometimes orangey.  They are good guys and help keep the bad ones under control. Unfortunately, the miticides you use to control the spruce spider mite also may kill the predatory mites so if you see both, scout over time and see if the numbers of bad guys are going down.  Then you don’t need to spray!

 

Ah, spiders – the bane of some growers existence.  Not that they are doing anything bad, it’s just the potential for their egg sacs to hatch out in people’s houses sending hundreds of babies up the walls. Not sure why that would bother anyone… Got my first picture of an egg mass this fall.  This one looked round and brown and papery but they do vary.  Usually some webbing holding it to the tree.  The grower is holding it in a jar to see if anything hatches out so we will see if I am right.

 

So what do you do?  There really isn’t anything to do but look carefully and shake the trees. I had a discussion with Dr. Raynor, the spider expert here, about creating alternative habitat so maybe I need to get back to that.

 

Hmm – it’s an all arachnid post.

 

Same old same old… not that we want more insect pests but a few could drop off the list….

 

Spruce spider mite – 2375- 2806 GDD

Doug fir needle midge – remove heavily infested trees (carefully so you don’t spread the pest) before larvae exit the needles (needles will turn brown). Mark infested trees for placing traps in the spring

Elongate hemlock scale – keep scouting for crawlers.

Cooley spruce gall adelgid – prune out galls on spruce before they turn brown (about 1850) – see other information on Cooley above

Cryptomeria scale crawlers – 1750-2130 GDD

Japanese beetle adults – 1029-2154 GDD

Two spotted spider mites– 1300-2000 GDD

Pine needle scale 2nd generation– 1290-1917 GDD

 

Have a great week!  Palindromic dates (same backwards and forwards) continue for a few more days!

 

September 5, 2019

GDD update 9.5.19

Sun on the lake!  I haven’t been in it yet as it is a little chilly…..but soon.  Sorry – that has nothing to do with Christmas trees.

 

Doing this email on GDD and pests has taught me a lot.  One thing is how confusing all the information can be.  My 2 main sources are the Cornell Tree and Shrub Guidelines (as we call it for short) and Pennsylvania IPM’s IPM for Christmas Tree Production.  And even with only 2 sources, there is confusion. Cooley Spruce gall adelgid fall treatment is a good example.  Admittedly, we are dealing with a pest with 2 hosts on which the insects behave somewhat differently and with a variety of pesticides.

 

Tree and Shrub says 1850-1950 GDD for fall control on spruce and 1500-1775 on Douglas fir, late fall for soil applications.

PA says 2800-3000 GDD for fall control of overwintering stages on their calendar.  In the specific chapters, it notes a single treatment in late September to early October for both Douglas fir and spruce to control exposed nymphs and immature females.  For spruce, it is recommended to treat after the first frost and that this is the most reliable time to treat.  Dormant oil for either species should be after the first frost when there is no active growth and the temperature is above freezing.   Depending on where you are, late Sept/early Oct and 2800-3000 might be the same time, but Long Island is predicted to break 3000 about Sept 10.

 

How do you figure out which is the right answer?  Trial and error sometimes.  And a little more research on my part.

 

The increase in GDD over the 5 day forecast is getting smaller it seems.  So there are not many changes in pest management.

 

Spruce spider mite – 2375- 2806 GDD

Doug fir needle midge – remove heavily infested trees (carefully so you don’t spread the pest) before larvae exit the needles (needles will turn brown). Mark infested trees for placing traps in the spring

Elongate hemlock scale – keep scouting for crawlers.

Cooley spruce gall adelgid – prune out galls on spruce before they turn brown (about 1850) – see other information on Cooley above

Cryptomeria scale crawlers – 1750-2130 GDD

Japanese beetle adults – 1029-2154 GDD

Two spotted spider mites– 1300-2000 GDD

Pine needle scale 2nd generation– 1290-1917 GDD

 

Have a great week!

September 1, 2019

GDD update 8.30.19

Another lovely day! I seem to be sitting here contemplating life and IPM conundrums.

How do you deal with control measures that you can’t do at the ‘right’ time?  Sometimes it makes a difference and sometimes you just need to know a bit more about the insect. For example, if we are talking about a scale insect that has a particular GDD range for crawlers, applying the appropriate pesticide must be done while the crawlers are out from under their mothers’ scale covers and before they form their own protective coatings or it is wasted.  What about removing trees with balsam woolly adelgid?  We recommend doing it in the winter so that the beasts are not active and maybe will stay put on the affected tree, or croak if they fall off.  Regardless, we worry about spreading them to surrounding trees so tarping any trees you are taking out or burning them in place, if allowed, makes sense.  So it can be done at any time – just be very careful.  Consider spraying any trees around them and along the route where you removed them.  This particular adelgid is too small to readily see.

 

What about things that look the same?  Cooley spruce gall adelgid and Doug fir needle midge – both on Doug fir. Yellowing and kinking of needles for both so you might need to do a little more sleuthing. The adelgid is forming a gall – albeit very small – so you might find a larva in the swelling on the needle.  Cooley’s has fluffy white egg masses in the spring on Doug fir.  Do you remember seeing that? (Insert plug for keeping good records here!).  They are different types of critters and treatment is not necessarily the same so good id is important!

 

And what’s brewing in bugland?

 

Nothing new – but they are all still out there for the scouting!

 

Spruce spider mite – 2375- 2806 GDD

Doug fir needle midge – remove heavily infested trees (carefully so you don’t spread the pest) before larvae exit the needles (needles will turn brown). Mark infested trees for placing traps in the spring

 

Elongate hemlock scale – keep scouting for crawlers.

Cooley spruce gall adelgid – prune out galls on spruce before they turn brown (about 1850)

Cryptomeria scale crawlers – 1750-2130 GDD

Japanese beetle adults – 1029-2154 GDD

Two spotted spider mites– 1300-2000 GDD

Pine needle scale 2nd generation– 1290-1917 GDD

 

August 23, 2019

GDD Update 8.23.19

I hope you are all enjoying this lovely day.  Might even make shearing pleasant.

 

I had a conversation with NEWA’s Dan Olmstead (the advantage of going to coffee break in the Geneva NYS IPM office!) and learned some useful news.

 

First – If you come to the Beneficial Habitat Twilight on Sept 26 (more info below) you can see the sensors we have in the Christmas trees that Dan is using to look at microclimates.  The idea is that with a base station, you could also have sensors in different parts of the field that might indicate that some pest management needs to start sooner in certain areas.  For what we are doing with GDD and Christmas tree pests, the GDD ranges are big enough that it might not make too much difference, but it could be an ‘early warning’ system.  Dan is going to get some information together for us to hand out at the meeting.

 

Second – It sounds like there will soon be less expensive base stations that still connect to NEWA.  You can always have your own independent weather station with just the measurements you need, but the advantage of being connected is seeing what is coming by looking at areas that warm sooner.

 

Third – NEWA is going to trial some kind of automated email system connected to pest models.  Maybe it will email you every day and give you information on the models you select.  The emails probably won’t be as rambling as mine, but they would come on a more standard schedule.  I’m working on him to use Christmas tree growers as a trial group, but that means I need to get all the models in.

 

And the advertisement – we are holding a Twilight meeting on September 26 from 5-7 in our Christmas tree plot at Cornell AgriTech in Geneva (what used to be called the Experiment Station).  We are primarily talking about the beneficial habitat plots – with Amara Dunn, Jason Dombroskie, and Maria van Dyke speaking about beneficials and the potential of habitat plots to provide pest management in the trees – but you can see how we are doing with the trees, too.  $15 gets you all the speakers, AND pizza. 1.5 Dec Pesticide Recertification Credits are available in categories 1a, 3a, 10, 24 and 25.  We are working on our registration page so you should see that pop up next week.

 

So what is happening right now?  Not much change.

 

Spruce spider mite – 2375- 2806 GDD

Doug fir needle midge – remove heavily infested trees (carefully so you don’t spread the pest) before larvae exit the needles (needles will turn brown). Mark     infested trees for placing traps in the spring

 

Elongate hemlock scale – keep scouting for crawlers.

Cooley spruce gall adelgid – prune out galls on spruce before they turn brown (about 1850)

Cryptomeria scale crawlers – 1750-2130 GDD

Japanese beetle adults – 1029-2154 GDD

Two spotted spider mites– 1300-2000 GDD

Pine needle scale 2nd generation– 1290-1917 GDD

 

Have a great week!

 

August 13, 2019

GDD update 8.13.19

I think this is the first time I have done the reading 5 days apart – which it how far out the prediction goes.  The predictions are remarkably good.  Most are no more than 10 points out (max was 20) and only one was lower than predicted by a few points.

 

Check out some other tools. The Climate Smart Farming GDD calculator lets you put in your address or click on the map for a location. I’m not sure where they get their data from and how it is calculated to a specific site.  My house in Ithaca is almost 100 GDD points lower than the campus location – but that is probably correct.  You can also put in several locations and compare them.

 

It is aimed more at crop development – for example, you can put in a planting date and the GDD Base that is the default is 50/86 as it is based on the fact that crops don’t develop much under 50 F and over 86 F.  You can choose other bases

 

By comparison, in the NEWA system we’ve been using I selected a March 1 start date, not because of planting but because we usually don’t have much insect development before that and the GDD accumulated in a spring thaw throws things off a bit.  Also, we use the GDD base of 50F with no upper limit – which isn’t perfect at very high temperatures, either.

 

The CSF system lets you put in a GDD target – for example, if you knew the second generation of spruce spider mites is expected to start at GDD 2375, you could put in a target of 2200 to give yourself some leeway and it will indicate for each site >2 weeks to target, <2 weeks to target or target has been reached.

 

Try it out!

 

There are several other tools under the Tools tab. An interesting one tells you climate change for your county since 1950 with a variety of different measures. http://climatesmartfarming.org/tools/csf-county-climate-change/

 

 

A few new things to add:

 

Spruce spider mite – 2375- 2806 GDD (notice how I worked that in above 😊 ) – for a few of you on Long Island

Doug fir needle midge – remove heavily infested trees (carefully so you don’t spread the pest) before larvae exit the needles (needles will turn

brown)

Mark infested trees for placing traps in the spring

 

And the others just keep rolling on:

 

Elongate hemlock scale – keep scouting for crawlers.

Cooley spruce gall adelgid – prune out galls on spruce before they turn brown (about 1850)

Cryptomeria scale crawlers – 1750-2130 GDD

Japanese beetle adults – 1029-2154 GDD

Two spotted spider mites– 1300-2000 GDD

Pine needle scale 2nd generation– 1290-1917 GDD

 

Have a great week!