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Injecting Bt for squash borers

I am expecting my old enemy the squash vine borer any day now.... this time I am planning to use Bt injected into the stems to hopefully kill them before they kill my plants. Has anyone done this, and if so, what were your results? I am assuming that I should dilute the concentrate as per the instructions and shoot a whole syringe-ful into each stem. Any advice on this?
Thanks!
 
I am very anxious to hear the answer to this one also. I have already had to replant my squash and hope to save these.
 
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I have it on good authority that putting water in the hole that the borer makes, makes it back right out...into a bucket of soapy water! Muah hah hah haaa!

Good luck.
 
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I tried that on my last plants but I had trouble getting the needle in the right spot and it kept pluging up the needle- think I'll try it again. Maybe a bigger needle next time. Thanks for your reply.
 
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I did this for a couple of seasons about 5 years ago and found digging them out with dental tools to be more effective and less time consuming.

You have to inject the Bt every day or it will not work and you have to start about 24 hours before the eggs are laid. Bt only works on the small size larva not the big or medium sized worms. It is also helpful to spray or dust the plants when you inject the plants
 
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I tried Bt injections recently -- here's what happened. I had 2 zucchini plants and noticed that one was wilting. I'd had no experience with squash vine borers so it was a few days before I figured out what was wrong, and noticed the tell-tale yellowish frass on the stem of the [u]other[/u] plant too.

It must have been [u]at least[/u] a week, maybe two, after I first noticed the wilting that I got a hold of a needle to inject with. Fortunately for me, I didn't have anything else that needed Bt at the time, so I was only mixing up a few syringe-fulls. But I could't measure out such tiny amounts with any accuracy so I ended up using a stronger solution than the bottle directions called for.

I injected at many different points along the main stem of both plants. The needle was pretty small so I too had trouble with it clogging. And it was hard to push the plunger in. I used several syringes full of solution to treat both plants.

After maybe a couple of weeks, the plant that had already started wilting didn't improve, so I yanked it and burned it. The other one kept going fine. After a few weeks, I did notice a weak point in the main stem where the top third of the plant seemed to be breaking off. Weak point caused by a borer??? So I cut if off at that point (alas, all the flowers were there, so they got cut off too) and left the rest of the plant.

The part I left is doing just fine, no wilting yet. But no flowers either. I'm leaving it in the garden to see if it will start flowering again.

I would definitely try the Bt injections again (I'm looking for a larger needle to make it easier) but will try to inject at the first sign of borers. That should be easier now that I know what to look for.

I like the water in the hole idea too, so I'll try that too.

Hope that helps.

Abitabar, zone 8b
(miss my lettuce; being buried under a mountain of green beans)
 
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The syringes I found were specifically called "garden syringes" from the Planet Natural catalog. I hope they will be big enough to not get clogged up, as severl people have mentioned. Will keep you posted on my success or failure!
Thanks!
 
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Spray or dust the plants with what?
 
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I have never had any luck finding them when I try to dig them out. About how far up or down from the hole do you look for them?
 
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How about a preventative tactic that I learned from friend who has been gardening for around 50 years?

When the squash first starts to set flowers, mist the entire plant. Then sprinkle wood ash all over the main stem and thicker part of the leaf stems. Make sure ash covers the main stem completely and in a small mound at soil level. Don't get ash on the flowers.

Repeat this every few days, after a rain or heavy dew, or as more stem gets exposed by good growth. If the ash cakes and hardens a bit, that's ok.

I've tried it with fairly good success. If you start this early enough, it does seem to discourage major borer infestation. I think this works because the slight caustic nature of the wood ash may not be a good habitat for the borer eggs.

Make sure that you use only firewood ash-- not the ash residue from those jiffy logs, burned lumber, or commerical barbeque charcoal.
 
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