is this damage from heat?

have Centennial and Chinook that have tan - white spots all over basically all of the leaves, though the newer ones have less. It was > 100 for a few days, and these were watered well the whole time. The spots still seem to be getting worse 2 weeks after the extreme heat even though its cooled down to 95-95 highs every day. I tried scratching at the spots and i cant see any powdery stuff like mildew that comes off.

That looks similar to my leaves which a garden center looked at under a microscope and told me it was mites. I sprayed the undersides of the leaves with organicide and cut off the ones towards the bottom (which looked like they had the most damage), and things are looking much better now.

I have that too except the lower the leaves, the more yellow. Also noticed tiny webbing on the undersides of some of the leaves...spider mites. I sprayed them down with a hose and used some insecticidal soap. It's been super dry in Indiana which is the environment they love.

Haven't been home since but I'm hoping for some improvement...

Definitely mites. I had this happen to several of my plants. Someone posted a picture of mite damage over time that matched this and someone else suggested spraying with a 50-50 mix of isopropol alcohol and water. Worked like a charm with one application, though they recommended doing it a few days in a row. I put the mix in a spray bottle and sprayed all the lower leaves, especially those that were changing colors as your pictures show...

G'damned mites, I've been battling the wee beasties for the last week, and while the carnage has been epic, I'm not actually sure who is winning the war at this point. The heat waves and dry spell have definitely brought them out by the gazillions here - pretty creepy to flip a leaf over and watch what appears to be the entire surface in motion.

What they lack in size they more than make up in numbers, and short of a blazing inferno there isn't much of anything that actually kills their eggs, so no "one and done" treatment here.

So far I've hit them with Neem Oil last week, then insecticidal soap this week (5 days later), and I'll hit them with something else five days from the last salvo. Then we'll start over again...

Cheers!

Talked with a family friend yesterday and showed her some pics of my plants. She just happens to be an entomologist and her specialty IS guess what, SPIDER MITES. Anyways she confirmed them in mine and said insecticidal soap and spraying the plants down with water will help eradicate them. So far it seems to be working well...

SkyHighBrew88 said:

Talked with a family friend yesterday and showed her some pics of my plants. She just happens to be an entomologist and her specialty IS guess what, SPIDER MITES. Anyways she confirmed them in mine and said insecticidal soap and spraying the plants down with water will help eradicate them. So far it seems to be working well...

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We now know who to PM when we can't figure out what is wrong with our plants

thanks everyone, I'm spraying with IPA every morning afternoon. I had 4 new plants with mites in pots in a different location, and I moved to about a foot away from healthy plants before i noticed this. should I be spraying the healthy plants too? maybe I should just get a good insecticide now since I wont be harvesting any hops from these small plants this year anyway.

SnidelyWhiplash said:

thanks everyone, I'm spraying with IPA every morning afternoon..

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LOL shouldnt you be drinking the IPA, and spraying bug stuff on the plants?:rockin:

the discoloring is called stypling. spider mites are leeching important fluids from the leaves and killing small areas. if you are spraying them (neem oil, alcohol, dawn dishsoap, etc) will kill the adult but you will need to continue treatment every few days. they will lay eggs and the eggs are not killed by these treatments. usually a big breakout with dry conditions. they are killed by common fungus in humid weather and are even knocked back by just water. once they seem like they are gone, they will comback so you need to stay on top of them. usually if you are fighting aphids, the mites will be kicked too. the plant will shut down flower production if it has too much damage but you can cut back the damaged leaves.

Same problem here. Going to spray once i harvest some hops.

I had a massive spider mite invasion this year due to the drought and the month of 100F+ weather we had. Now that we have had some nice rainfall and cooler temps the plants have alot of side arms from bines i thought were dead and gone. I'm using a pyrethrin/neem combo once a week and using a slow release organic fertilizer with a newly set up drip irrigation and that has seemed to make all of the difference.

Just an update. I checked the plants yesterday and saw no webs/mite poo, so I guess the water spraying and insecticidal soap did the job. Boy I wish I'd of known what was going on earlier. Some of the lower buds that dried up brown with the leaves very well could've been more hops. Just glad I'll get some kind of harvest though...

Only good way to check is to use a magnifying glass