Squash-Borer Nightmares

[uggabugga]

I really hope someone may be able to help me out with this problem. for some reason, the last two years I've planted squash and pumpkins, they've been anhilated by vicious squash-borers. the first season I wasn't really aware of the cause, only that my healthy, vigorous plants started wilting and would eventually die by august. last season I observed what I took to be a brightly colored wasp; not wanting to hurt something that might be beneficial, I left it alone, and then looked it up on the internet- then regretted not killing it when I had the chance!
not that killing them is an easy task, they are incredibly fast and agile, much like a housefly. they lay eggs at the crown of the plant, and the resulting grubs eat the stem from the inside out. out of desperation I've even tried slitting open the crown, rooting around inside with a piece of wire, and taping it back together, but this rarely works since you really can't see what you're doing, and if you leave even one intact, that's enough to kill the plant.
a general insecticide is worthless b/c the larvae are protected inside the plant, and a systemic may be a problem since I want to eat what I grow.
the only thing I've come up with, but not tried yet, is to inject some Bt toxin into the crown of the plant with a hypodermic needle. other than that, I'm completely out of ideas. any help would be greatly appreciated...

[decam0]

how about horticultural fleece around the plant or around the whole bed to stop the little blighters getting in?

[opabinia51]

This is very interesting, thanks for the post.

I would do a little research and find out what eats this wasp and plant plants that will attract the predator. Take a look at the beneficial insects thread in the organics section to get a general understanding of what plants to plant to attract beneficials.

[uggabugga]

how about horticultural fleece around the plant or around the whole bed to stop the little blighters getting in?

horticultural fleece? never heard of it. anything that would surround the base of the plants might have some chance of working...


obapinia - the only thing I've found concerning natural predators is trichogramma wasps. those might be something to keep in mind for next season, but I think it's too late for them to do much good now.

anyway, I have a little update- I was previously under the impression that these wicked moths oviposit below the surface of the stem, but yesterday found out that they lay small, brown eggs on the surface. immediately I went outside and started checking, and sure enough, every single one of my 50+ squash and pumpkin plants were just peppered with the things around the crown, especially around the very lowest part right at the soil line. so I spent the next two hours cussing and scraping them off with my pocketknife

I took a picture but will have to post it later. no doubt when I go out and look after work today, there will be more to be scraped off. maybe there's some sort of horticultural oil spray I could dowse with that would keep the eggs from adhering and/or keep the moths away in the first place?

(picture from u. of kentucky website) [img]https://www.uky.edu/Ag/Entomology/entfacts/images/svbadult.jpg[/img]

it's strange that these borers are so bad in my immediate area; they grow great gobs of pumpkins not far from here, and when I asked them last fall how they dealt with squash borers, they claimed to never have had a problem with them.

<edit - here's a picture of a pumpkin plant with borer eggs at the base; tiny brown things a little smaller than squash bug eggs >

[img]https://img163.imageshack.us/img163/9305/eggs4wt.gif[/img]

[uggabugga]

*bump*

I've never tried neem oil - anyone think this might work?

[decam0]

Horticultural fleece is sold in garden centres here in the UK. I would be surprised if it's unavailable where you are. Maybe it's called something else? Anyway, it's an unwoven lightweight fabric, and is used as insulation to keep frosts off early plantings, and to keep bugs at bay. It's sold in pieces about a metre wide and various lengths and weights, and is usually white or grey.
Delia

[LoreD]

Horticultural fleece is called row cover or frost blanket here in the U.S. It looks like cheesecloth. It is available at all gardening centers and hardware stores.

I saw a picture in a book where aluminium foil was wrapped around the base of pumpkin or squash like a collar to prevent the squash borer from laying the eggs. Also, radishes planted near the base of the pumpkin deter the squash borer from laying the eggs. I have seen the squash borers move away from the pumpkin mounds planted with radishes. Also some sites recommend covering the vines with dirt or mulch and leaving only the leaves and flowers showing.

LoreD

[uggabugga]

decam0-
ah, now I get what you're talking about. thank you for the suggestion, but I don't think what I know as row cover material would work for me, there's just too much square footage that would have to be covered. plus, how can insects get to the flowers to pollenate?

I saw a picture in a book where aluminium foil was wrapped around the base of pumpkin or squash like a collar to prevent the squash borer from laying the eggs. Also, radishes planted near the base of the pumpkin deter the squash borer from laying the eggs. I have seen the squash borers move away from the pumpkin mounds planted with radishes. Also some sites recommend covering the vines with dirt or mulch and leaving only the leaves and flowers showing.

LoreD

foil - that's an interesting possibility. I've tried saran wrap but it keeps falling off after watering. so these little buggers don't like radishes? that I will definitely have to try, altho the canopy beneath those giant leaves is almost enough to keep even weeds from getting much of a hold.

I already lost one of my larger pumpkin plants over the weekend. right now I'm getting down on my hands and knees and scraping off the eggs with a pocket knife, then heaping soil up around the base. but after every watering or rain the soil gets dislodged, plus they've started laying eggs on the lateral stems as well as the crown
I've given a couple of sprayings of [url=https://www.bugspray.com/catalog/products/page1897.html]Thuricide[/url], a systemic Bt toxin specific to lepidopterans, applied with a hand sprayer.

I managed to stun and kill a couple of them yesterday as they were resting on a leaf:
[img]https://i6.tinypic.com/1z52drs.png[/img]

[underthemagnolia]

After losing my zucchini plant to SVB grubs I did some research.

Apparently the window for egg laying is relatively narrow and once it's over you shouldn't have any problems. So, floating row cover for the early part of the season is supposed to be very helpful (for a number of pests).

Also, beneficial nematodes apparently LOVE to eat SVB grubs or eggs. They also like to eat Squash Bugs which I gather are NOT limited to early spring.

Here in Georgia I have the luxury of starting again from seed. Hope springs eternal with a long summer.

Good Luck.
Pixie

[uggabugga]

After losing my zucchini plant to SVB grubs I did some research.

Apparently the window for egg laying is relatively narrow and once it's over you shouldn't have any problems. So, floating row cover for the early part of the season is supposed to be very helpful (for a number of pests).

Also, beneficial nematodes apparently LOVE to eat SVB grubs or eggs. They also like to eat Squash Bugs which I gather are NOT limited to early spring.

Here in Georgia I have the luxury of starting again from seed. Hope springs eternal with a long summer.

Good Luck.
Pixie

thanks, pixie.

I may have to disagree with your analysis, tho

they're not as thick as they once were, but I'm still seeing some adult borers resting on leaves, so that's close to two months that they've been out wreaking havoc. and the worst thing about it is that even tho the adults may be clearing off, the larvae are inside my plants like a ticking time bomb.

I dislike doing it, but I put a pinch or two of a synthetic systemic in the ground at the base of a couple of my most promising pumpkin plants to see if it will help. I've already lost 2 pumpkin and half a dozen zucchinis.

aren't nematodes confined to living in the ground? because the borer eggs are above ground and the larvae are inside the stems...