# Is anyone watching GDD?



## Stressbaby (Jun 13, 2019)

It feels like it's cooler than usual so far in June, and my Norton really seems to be sort of sluggish. So I started watching my GDD numbers. Through 6/12 using bud break 4/16, I have 869. I don't see a way to compare that to average starting on 4/16, but starting 1/1/2019 the site confirms we are behind by around 200. 

Anyone seeing the same thing? Any early thoughts on impact?

Using this link: https://pnwpest.org/NC/ddmaps.html


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## GreginND (Jun 13, 2019)

Yes, we are behind by about 350 right now here in the Fargo area - 975 this year vs 1323 by this time last year.


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## BigH (Jun 13, 2019)

Behind normal by about 90 in central Iowa. Behind last year by 190. We normally accumulate around 3400 GDD between March 1 and Oct 1, so I have always felt like I had heat energy to spare. This year might test it a bit.

PS I use the same GDD as corn, which has a base of 50 degrees. 

H


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## sour_grapes (Jun 13, 2019)

I don't know about the GDD here, but it is mid-June, and I would like to finally ditch the wool blanket I've been sleeping under!


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## Masbustelo (Jun 14, 2019)

Yesterday I started off the day with shorts and tee shirt, then went for my stocking hat, then went back for a sweatshirt and zipped it up. 50 degrees at 7:30 am.


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## Johnd (Jun 14, 2019)

Wish I could share the wealth, we’ve been in the 80’s since March and April, some 90’s in May that are probably here to stay through September. GDD to spare....


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## wxtrendsguy (Jun 14, 2019)

GDD might play a role but last year and again this year we are ahead of normal mainly due to overnight low temperatures being elevated due to excessive rainfall. The key missing ingredient is sunshine....our growing season GDD were way above normal last year but continuous cloud cover and rain never allowed the grapes to achieve more than 18 brix.


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## wood1954 (Jun 27, 2019)

I'm about 300 gdd behind last year, might explain whythe vines seem to be growing slowly, flowers have been open for over a week I hope there is enough time to ripen.


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## Dennis Griffith (Jun 28, 2019)

I'm not sure where we stand in Ohio, but we are behind. For instance, haven't seen a single Japanese beetle yet this year. I usually start the fight around mid June. Or maybe they've all drowned this year, but such is not my luck. They have, however, been replaced with fungus humongous.


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## Stressbaby (Jun 29, 2019)

Same here, no beetles so far. Have been keeping up with sprays, however, so the vines that didn't drown look OK.

I made this post last year on 6/24 when I came back from vacation to terrible Japanese beetle damage (the vines appear to have fully recovered btw). 

My GDD calculator today says we are at 1168, 14 days behind 2018, 3 days behind 2017, and 2 days AHEAD of the 30y average.


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## Dennis Griffith (Jun 29, 2019)

Me and my big mouth. I started picking off a few JBs today. This makes them 2 weeks late here.


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## wood1954 (Jun 30, 2019)

while spraying the vineyard this afternoon, I spied my first JB. along with the Imunox fungal spray I added permethrin which works ok. its my last application of permethrin because it sticks around too long. Also scared up 2 grape berry moths hopefully the permethrin works on their eggs as I wont spray again for a week.


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## Dennis Griffith (Jun 30, 2019)

I must say, their arrival this year is weak. Usually, I get up one morning and they have moved in by the bus load. Last year it was bad.


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## Dennis Griffith (Jul 1, 2019)

wood1954 said:


> while spraying the vineyard this afternoon, I spied my first JB. along with the Imunox fungal spray I added permethrin which works ok. its my last application of permethrin because it sticks around too long. Also scared up 2 grape berry moths hopefully the permethrin works on their eggs as I wont spray again for a week.



I have found that the new Sevin based on Zeta-Cypermethrin is VERY effective for JBs. I have had other products not work as well as expected in the past. If the season is bad (like last year), I throw in 
Ortho Flower, Fruit and Vegetable Insect Killer (Acetamiprid) for one of the spray cycles.


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## Obbnw (Jun 3, 2020)

Those of you using GDD do you use temperatures you measure or some other way. Do you limit the upper temperature? If so to what?

I regularly have very hot summer temperatures but I haven't noticed a slow down in growth in the hot weather. Maybe with the dry air (when it is hot the humidity is usually less than 20%) the grapes interal cooling is more effective and can handle hotter temps?

Just curious - I started looking at GDD's more closely and may start to follow it. Seems like the best predicting tool.


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## Dennis Griffith (Jun 3, 2020)

I suppose I pay attention to the GDD somewhat in that it is one of the variables I check. I live in Ohio and the weather can be crazy here. They say (here) that if you don't like the weather today, wait til tomorrow. Mostly, I watch the vines as they seem to be more in tune with nature, not counting late frost or early warm spells, but those are outlyers on the averages.


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