Squash Bugs and Squash Vine Borers - What I Learned This Year

[brownrexx]

I have fought the SVB for years and tried all of the remedies like foil around the stem to no avail. Here is what works for me.

I purchase Thuricide which is a bt solution made by Bonide.

I dilute it as recommended on the bottle and use a syringe with an 18 gauge needle to inject it into the squash stems about 6 inches above the soil level.

Since the stems are hollow, the solution runs down the inside and coats them and any SVB caterpillars that are present. You can wait until you see signs of caterpillar poop (frass) but I usually inject after the plant starts to flower because I KNOW that those sneaky SVB moths will have laid eggs when I wasn't looking.

I also plant a second crop at about this time so that when/if the first crop dies, then I will have more producing.

This has worked well for me over the last 2-3 years and I have had plenty of zucchini which I really like.

[Nattybo!]

Eldemila, your experience with vine borers and squash bugs this is exactly the same as mine. Too many and too fast. You definitely know what you are looking at and you definitely know what to do.

Zeroma, squash vine borers most definitely lay eggs! And anywhere along the vine, in singles, sometimes pairs, usually at the stem base but I have seen them laid near the end of a leaf stem. And the squash vine borers fly during the daylight hours even though they are moths. And yes, they are fast. They do not fly in a straight line but more of a zigzag.

[zeroma]

Originally Posted by Nattybo!

Eldemila, your experience with vine borers and squash bugs this is exactly the same as mine. Too many and too fast. You definitely know what you are looking at and you definitely know what to do.

Zeroma, squash vine borers most definitely lay eggs! And anywhere along the vine, in singles, sometimes pairs, usually at the stem base but I have seen them laid near the end of a leaf stem. And the squash vine borers fly during the daylight hours even though they are moths. And yes, they are fast. They do not fly in a straight line but more of a zigzag.

Yes Nattybo, I guess what I think of as the squash vine borer is the 'worm'/larva part of the life cycle and the adult that does the egg laying is the moth.

The adult moth does lay eggs along the stem of the plants. If I said it wrong, sorry, I was trying to explain but guess I didn't say what I thought I wanted to. Distracted with the dog poking his nose on the keyboard at the time wanting to go outside...didn't mean anything offensive.

[zeroma]

Originally Posted by brownrexx

I have fought the SVB for years and tried all of the remedies like foil around the stem to no avail. Here is what works for me.

I purchase Thuricide which is a bt solution made by Bonide.

I dilute it as recommended on the bottle and use a syringe with an 18 gauge needle to inject it into the squash stems about 6 inches above the soil level.

Since the stems are hollow, the solution runs down the inside and coats them and any SVB caterpillars that are present. You can wait until you see signs of caterpillar poop (frass) but I usually inject after the plant starts to flower because I KNOW that those sneaky SVB moths will have laid eggs when I wasn't looking.

I also plant a second crop at about this time so that when/if the first crop dies, then I will have more producing.

This has worked well for me over the last 2-3 years and I have had plenty of zucchini which I really like.

I'm just curious if you use good crop rotation with your method also? I like this method you describe.

[gorbelly]

Originally Posted by zeroma

What you think is the squash vine borer isn't. You are picking off Squash bug eggs, they will lay eggs on and under leaves in little clusters of brownish red color. The adult of the svb looks like a wasp/moth. The svb has a different lifecycle from the squash bug.

It's possible to pick off SVB eggs. They're quite visible down by the base of the plant, but they don't get laid in clusters. However, they can lay the stray egg further up or on a leaf or down just under the soil line, and you only need to miss one to lose a plant.

Originally Posted by zeroma

What you wrote:
"The SVB, there's not much I can do, they are too fast and too many. They are still out there laying their eggs. This is late for them compared to last year. I have pulled out a good 50 worms from my plants. About 6 a succumbed to their death from the borer, unfortunately."

My question, what is it that you are saying are too fast? a bug or a worm? When do you "see" the SVB? It isn't the SVB that lays the eggs. I think you are still seeing something other than SVB which is the larva (worm) which doesn't lay eggs, but grows inside the stem of the plant.

My understanding was that "too fast" meant the speed at which the borer takes the plant down. They really do seem to kill plants overnight. One day, the plant looks fine. The next day, everything is wilting, and even doing SVB "surgery" only has a small chance of saving the plant. It seems like the borer just reaches a critical size one day and kills the plant overnight as opposed to in a way that gives you warning symptoms in time to do something.

[brownrexx]

Originally Posted by zeroma

I'm just curious if you use good crop rotation with your method also? I like this method you describe.

I do rotate my crops but it really doesn't help for preventing the SVB. They can fly for up to 2 miles and my garden is not THAT big!


As for taking down a plant quickly -it's not really as quick as you think. The SVB takes several weeks from egg to large, plant killing larva. It just seems like the plant dies quickly because we don't notice that it is infected until the damage is already done and it is ready to die. The plant survives with the larva inside for several weeks. From the SVB's point of view, the plant has to survive long enough for the larvae to grow to a mature size so that they can pupate.

[gorbelly]

Originally Posted by brownrexx

I do rotate my crops but it really doesn't help for preventing the SVB. They can fly for up to 2 miles and my garden is not THAT big!

I think crop rotation is really just the issue when you want to use a row cover strategy, right? Because if you don't rotate, you risk having moths hatching from pupae in the soil and mating and laying eggs anyway despite the trouble you've gone through to cover and hand-pollinate your squash.

Originally Posted by brownrexx

As for taking down a plant quickly -it's not really as quick as you think. The SVB takes several weeks from egg to large, plant killing larva. It just seems like the plant dies quickly because we don't notice that it is infected until the damage is already done and it is ready to die. The plant survives with the larva inside for several weeks. From the SVB's point of view, the plant has to survive long enough for the larvae to grow to a mature size so that they can pupate.

Right. But from our point of view, it's easy to miss tiny bore holes, and it seems like the plant is a goner overnight. Even diligent and experienced gardeners experience the heartbreak of walking out one morning and realizing that the borers killed one of the plants that looked 100% fine the day before. It's not like a pest that takes down plants by defoliation.

[brownrexx]

Originally Posted by gorbelly

I think crop rotation is really just the issue when you want to use a row cover strategy, right? Because if you don't rotate, you risk having moths hatching from pupae in the soil and mating and laying eggs anyway despite the trouble you've gone through to cover and hand-pollinate your squash.



Right. But from our point of view, it's easy to miss tiny bore holes, and it seems like the plant is a goner overnight. Even diligent and experienced gardeners experience the heartbreak of walking out one morning and realizing that the borers killed one of the plants that looked 100% fine the day before. It's not like a pest that takes down plants by defoliation.

This is true but I roto till once a year in the Fall which hopefully exposes the pupae to bird predation and death from the cold in the winter months. I tried row covers one year and still got SVB so now I use the bt as a preventative and it seems to work better for me. I also had trouble with row covers because the zucchini plants got so big that they created gaps in the covers and that is probably how the moths got inside and infected them. I had grown a parthenogenic variety that does not require insect pollination so I did not open the row covers to hand pollinate.




Yes, it definitely seems like an overnight event to us but according to PA State entomologists the larvae feed for 4 weeks before killing the plant. This is probably why I have good luck with injecting the bt into the stems before I even see any damage. if you wait until you see the damage, then it will probably be too late. I know that they will infect my plants so I inject the bt as a preventative. It is the only way I feel confident that I will have zucchini.

http://ento.psu.edu/extension/factsh...ash-vine-borer

[gorbelly]

Originally Posted by brownrexx

Yes, it definitely seems like an overnight event to us but according to PA State entomologists the larvae feed for 4 weeks before killing the plant. This is probably why I have good luck with injecting the bt into the stems before I even see any damage. if you wait until you see the damage, then it will probably be too late. I know that they will infect my plants so I inject the bt as a preventative. It is the only way I feel confident that I will have zucchini.

http://ento.psu.edu/extension/factsh...ash-vine-borer

Some people refuse to use Bt or don't know about it. All I meant was that, for many people, their experience of squash vine borers is that they seem to kill plants overnight. I'm not disputing that the SVB actually takes a long time to kill the plant. If one is not aware of preventative methods that actually work (a lot of the "home remedy" methods don't), then the plant dies very quickly from the moment one notices symptoms, and that's just how I personally interpreted eldemila's original statement about how SVBs are "too fast".

I think your advice to inject Bt preventively is great. I'm not disputing that, either. A lot of advice sources say it doesn't work, but they generally are talking about injecting it after symptoms are noticed already, at which point, the damage is usually too extensive, and the plant is a goner no matter what 9 times out of 10. I've had luck with injecting Bt and spinosad at the first sign of a bore hole, but I don't grow more than 3 or 4 squash plants. I think checking over vines that carefully could be hard for people who grow a lot of squash. So your advice to inject it before borer activity is seen is a really good idea, especially for people who live in places where there are multiple generations of the SVB.

[brownrexx]

I interpreted the "too fast" as the SVB moths are too fast to catch. I have often seen one on a plant and I try to grab it to no avail. It's like trying to swat a fly with your hand.

Using bt is the only way I would ever get any squash. I have never tried spinosad but it's good to know that it works too. I only grow 4-5 summer squash plants.

[zeroma]

browrexx...since you have this method under good understanding, how about you ask a facebook blog about it. It is "the garden professors" on facebook.

https://www.facebook.com/groups/Gard...c_ref=NEWSFEED

They will dig up only science based - peer reviewed papers and give their reply. I don't want to take your idea and post there because I'm sure I'd get something wrong in my way of saying what you already understand. I love asking them for their help because you get science not myths.

z

[brownrexx]

Please feel free to ask them if injections of bt into the squash stem are effective. I am not a big Facebook user.

There are lots of reliable postings online that say it does work. Here is one of them, but there are many more and I have seen firsthand that it does work in my garden. bt kills caterpillars and larvae so it is natural to assume that coating the interior stem tissue with bt will kill the SVB larvae that are eating it. I have also heard that spinosad injections will work but I have not tried them.

http://articles.extension.org/pages/...arming-systems

Here is an excerpt if you do not want to read the entire thing.

Stem injections of Bacillus thuringiensis (Bt) are frequently recommended for squash vine borer management, especially for organic gardeners. Trials in South Carolina compared spray application and stem injection of commercial formulations of Bt with a conventional insecticide and an untreated control (Canhilal and Carner, 2007). The injection and spray application methods produced similar results, and the Bt treatments provided control similar to that of the conventional insecticide.

I am an organic gardener so I prefer this to application of conventional pesticides. Since the results are similar, why add pesticides to your plants?

[b54red]

I have been keeping them off my plants for years with a rather simple technique. I use a small bulb duster and dust the lower stem with a good coating of Sevin up to where the blossoms are. I do not dust blossoms or anything above open blossom area and have had no problem with SVB starting higher up the plant but I don't doubt they can. Every time there is a heavy rain and the Seving is washed off I just walk down the row and dust the stems of course as the season goes along the dusting has to go further up each time. I eventually get sick of squash and just let them go or pull them up but I haven't last any plants to SVBs in years using this technique. The only problem would be a long rainy spell but that hasn't happened so bad that I couldn't keep the Sevin on them but I could see it happening and if it does I might try the BT injections.

Bill

[Father'sDaughter]

I get hit with SVB every year, but have yet to loose a zucchini plant to them. I only grow two that are both bush varieties (vs vining), so only one very short main stem.

The minute I see SVB frass, I go digging into the stem with a pair of sharp pointed garden scissors until I find them and then chop them up. It's amazing how healthy and productive the plants are even after I've hacked the heck out of the stem to the point where it's barely half attached!

This year I have eight plants and only two have been attacked and both are still producing.

[brownrexx]

I do not use chemical insecticides but I thought that once a week dusting sounded like a lot of Sevin to apply so I looked up the Sevin label and for squash it says that the maximum number of applications is 6.