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Help - Spider mites?

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Help - Spider mites?

Posted: Tue Jul 08, 2008 9:29 pm
I think I have spider mites.
Leaves turning papery brown, spotted and slight web coating on several.
Small nat looking bugs in very fine web, that looks like thinned out cotton candy.

I sprayed with some very diluted Malythion but it also looks like the hops are just starting to form (first year vines Fresno, CA)! Maybe a few 1/16 to 1/8 inch buds on side shoots.

So, no more spraying from here on, but I am concerned on how to stop the infestation.

Any ideas, that won't hurt the hops for use? Dusting?


Re: Help - Spider mites?

Posted: Sat Jul 12, 2008 7:30 pm
by mfischer2
Once the insecticide wears off, you could buy some lady bugs, I got 1500 for about $7 from a local nursery here.

Re: Help - Spider mites?

Posted: Sun Jul 27, 2008 11:44 am
Well, still trying to kick these little guys! Sprayed a bit more with organic mite soap, but not much help.
Recently tried some Ortho, but trying not to spray top where cones are...

First year of hop growing in Fresno, CA is slowly turning into a dissappointment! But I won't give up!

Chinook - has lots of growth, and 30-40 flowers/cones 1/8" to 1/4", but many are shriveling up at this point. Starting at lower level and working there way up. I hope some of them survive.

Mt. Hood - Lots of growth, very little signs of cones, a few which are not open yet.

Sterling - Single tall bine, smaller leaves, some yellowand pale green leaves, no sign of cones.

EKG - died at 6"-8"

Any ideas are welcome...

Re: Help - Spider mites?

Posted: Sat Aug 02, 2008 3:01 pm
by Madtown Brew
First things first, be sure of your identification. Spider mites are pretty easy to identify. They like to hang out on the underside of leaves, and they make a fine webbing that can cover much of the plant in heavy infestations. First signs of spider mites are a light speckling of the leaves, almost like reverse color freckles. One of the more common mites is the two-spotted mite, which can easily be indentified by eye or with a magnifying glass. Here's a couple pics of the 2-spotted spider mite:



Mites love hot and dry conditions. Obviously, most of us can't move our hops into the shade, but for those who can, that is an option that may help a little. There are also many chemical controls available. One must take care not to spray with any pesticides that are not labeled for food crops. In addition, I would avoid any chemicals that are labeled as systemic, unless you know what your doing and are certain they are safe. Make sure you read the label carefully before purchasing or using any product.

For those who wish to be organic, things are more difficult. My suggestion would be to use a organic insecticidal soap. While less effective, it can provide a modicum of success as long as you spray every-other day. It is important to make sure that you achieve adequate coverage of all surfaces of the plant, especially the undersides of the leaves. The soap will only work if it actually contacts the bugs. I would refrain from spraying with ANYTHING within about 4 days of harvest.

I have also heard of people making a steeped tea out of cigarette butts. Nicotine is highly toxic to most insects yet it degrades rapidly in the sunlight. However, I'm not sure about any lasting smell or flavor impact of this method. I doubt that it would be organic either, unless the smokes you used were organic. I have no experience with this though and cannot recommend a process for making the spray.

Good luck

Re: Help - Spider mites?

Posted: Wed Aug 13, 2008 10:01 pm
by Rails
I live in Fresno/Clovis, CA too. I grow Cascades (2nd year). Spider mites are a big problem here for hops. I spray early before flowers appear. I use a Malathion solution based on the bottle's directions for vegtables or fruit. I soak the underside of the leaves once a week in the beginning of the season when I first see the mites. Once the bines are about four or five feet high I cut off the first foot or two of leaves from the bine. This will help from getting more mites.

I also have gotten some caterpillars. I used the Safer Caterpillar Killer product (BT) in a diluted form. It's organic so once I have flowers I still can spray. Once I get flowers I will only use insecticidal soap and BT, no poisons. Hope that helps. In about a month I will be brewing my first Wet Hop Pale Ale. Good Luck!

Re: Help - Spider mites?

Posted: Thu Aug 14, 2008 2:20 pm
by Madtown Brew
Just started to get my first mites here, and right when the Goldings are ready to pick :x . Spraying soap on all the plants 2+ days from harvest. Got to hit them every other day to reduce the infestation.

Re: Help - Spider mites?

Posted: Thu Aug 14, 2008 2:38 pm
by dmtaylor
I know it's too late now... but the BEST thing you can do is to prevent the spider mites from taking hold at all, or at least delay them. I insecticided the heck out of my plants all summer, and the plants were doing great... until I got lazy and didn't spray them for a while. Now the spider mites have invaded and my leaves are all shriveled up. But at least the hops are ready to pick now, so I held them off long enough so the bines didn't all die early like they did last year. Just remember in the future to insecticide them, anytime you see the tiniest invasion of mosquitoes or anything at all, kill them dead. You don't want your hops to be a safe haven for any bugs. Kill them bastards, kill kill KILL, I say! :twisted:

Re: Help - Spider mites?

Posted: Sat Aug 16, 2008 6:15 am
by mr x
I've been using SM-90 for the last few days. I'll let you know how it turns out. I've used it indoors with great success.

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