Should I prune off bug damage?

[JCBurg]

greetings again forum! The war against Japanese beetles is on and I find myself on the front lines. Last year almost every plant was stripped bare I. The yard but this year we are having some success in fighting them and keeping the foliage full and healthy. My question for you grape growers is, should I prune off the damaged and eaten leaves to make room for more? Some are damaged past doing any good for the plant, and are still taking nutrients I suppose. I’m asking because I just thought of it while outside and wondered if anyone could give me a definite answer? Thank again!

 

[balatonwine]

Defer to give specific advice without seeing the damage (i.e. photos), but in general grape nodes on stems will usually regrow new leaves to replace damaged significantly leaves.

 

[JCBurg]

Defer to give specific advice without seeing the damage (i.e. photos), but in general grape nodes on stems will usually regrow new leaves to replace damaged significantly leaves.

That’s fair, I will get some photos posted this afternoon of what I am seeing.

 

[JCBurg]

That’s fair, I will get some photos posted this afternoon of what I am seeing.

Here are some of the damaged leaves

 

[Stressbaby]

That's not really bad. This is bad.
I was always taught as long as there was green, there was photosynthetic capability in that leaf, so leave it.
And I'm no expert, but I'd say the JB are the lesser of issues here. It looks to me like a serious case of downy? powdery? mildew.

 

[KevinL]

If I had to guess I'd say the white stuff is for killing the beetles. Unless that's not what you were referring to in the pictures.

 

[Stressbaby]

Could be something like powdered Sevin. Await OP reply...

 

[Dennis Griffith]

I'd leave the leaves on. If the vine can't use them then it will discard them. I recommend Garden Tech Liquid Sevin, which is no longer based on Carbaryl, and does a great job at eliminating the pesky little beetles. I use it in conjunction with setting traps out away from what you're protecting, and treating areas near the vines with milky spore. I add a little more of the milky spore each and it can be bought on Amazon in 20 pound bags. If you don't have the space to set up the traps away from the vines, then don't use them as they will attract the beetles (hopefully away from the vines).

 

[JCBurg]

That's not really bad. This is bad.
I was always taught as long as there was green, there was photosynthetic capability in that leaf, so leave it.
And I'm no expert, but I'd say the JB are the lesser of issues here. It looks to me like a serious case of downy? powdery? mildew.

No it’s not mildew it’s sevin powder! Lol

 

[JCBurg]

I'd leave the leaves on. If the vine can't use them then it will discard them. I recommend Garden Tech Liquid Sevin, which is no longer based on Carbaryl, and does a great job at eliminating the pesky little beetles. I use it in conjunction with setting traps out away from what you're protecting, and treating areas near the vines with milky spore. I add a little more of the milky spore each and it can be bought on Amazon in 20 pound bags. If you don't have the space to set up the traps away from the vines, then don't use them as they will attract the beetles (hopefully away from the vines).

I see several responses, thanks for looking in everyone. It sounds like, no don’t cut off the eaten foliage, leave the vine to shed it off and try to move the beetles somewhere else. The liquid sevin I think will be a great idea because the powder really makes the plants struggle for photosynthesis it seems.

 

[BigH]

My vote is to just leave it. At this point, you are using photosynthesis to build roots. Some of those leaves are ugly, but they are still harnessing the sun's energy. The vine will probably push some new growth to compensate for the damage, but you are likely to freak the vine out, as the kids say, if you start hacking off green tissue now.

H

 

[BigH]

I recommend Garden Tech Liquid Sevin, which is no longer based on Carbaryl, and does a great job at eliminating the pesky little beetles.

This is an important detail I overlooked

• New liquid forms of Sevin in red bottles == zeta-cypermethrin : pre-harvest interval of only 1 day for grapes
• Powder and granule forms of Sevin == carbaryl phi of 7 days for grapes
• Sevin SL liquid concentrate == carbaryl
• Old jug of liquid Sevin sitting in your cabinet == probably carbaryl, but better check

Best to read the label of course.

H

 

[Dennis Griffith]

This is an important detail I overlooked

• New liquid forms of Sevin in red bottles == zeta-cypermethrin : pre-harvest interval of only 1 day for grapes
• Powder and granule forms of Sevin == carbaryl phi of 7 days for grapes
• Sevin SL liquid concentrate == carbaryl
• Old jug of liquid Sevin sitting in your cabinet == probably carbaryl, but better check

Best to read the label of course.

H

Exactly. Which is why I changed to the new version of Sevin (and why I pointed out the brand name). And you are on the money with always read the label, again and again. And you haven't read it for a while, read it again. I download all the labels of stuff I use in pdf format onto my PC so that I can read it a little larger than what it says on the bottle (old eyes). Plus I can copy parts out and add to my spreadsheets.