Squash vine borer sightings

gamebirdJuly 8, 2009

I dug five or so squash vine borers out of my plants today. Ew. They were in my squash and pumpkins. Nasty things. I think (hope) most of the affected plants will survive. For the plants that had vined out, I firmed soil over part of the vine to encourage it to root, but that was only six of them. The vegetable marrow and yellow squash are bushed and there isn't a good place to encourage them to root.

This is just FYI for anyone else growing squash in Oklahoma.

I think I heard from someone that SVB comes in two waves here. One's bad enough, but when should I expect another assault? Or does it just continue erratically?

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Okiedawn OK Zone 7

Game Bird,

The second assault varies but generally 4 to 8 weeks after the first one.

Some years my plants survive the SVBs and some years they don't. Generally, the butternut squash is the one most likely to survive. I usually plant a fall crop of winter squash and pumpkins about the time the SVBs show up and attack my spring-planted crop.

With the fall crop, I start the seedlings in cups and then, when it is time to transplant, I cut the foot section off a knee-high stocking and discard that foot section, leaving me with a stocking "tube" and pull it over the stem, covering the area between the first leaf and the root. THEN I plant the seedling in the ground, making sure the lower end of the stocking is buried in the soil. You can use a rubber band to somewhat loosely hold the stocking 'closed' just under the leaf. The stocking keeps the SVBs from infiltrating the main stem, and both the stocking and the rubber band expand as the stem grows so that growth is not constricted. Piling up dirt on vines as they run does help too as it encourages the plants to root into the soil in numerouse places.

Gardens Alive has a great SVB page with advice from Mike McGrath, former editor of Organic Gardening magazine, which hasn't been nearly as good of a magazine since he left it a few years back. I've linked it below in case it might suggest something you haven't tried yet.

I haven't see any SVBs yet, but because I just said that, I am sure they will show up today or tomorrow because all gardeners know you bring insects upon yourself and to your garden just by saying "I don't have those here".

Good luck,


Here is a link that might be useful: Gardens Alive SVB Page

    Bookmark   July 8, 2009 at 6:38AM
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how do you know if you have them?

    Bookmark   July 9, 2009 at 12:36PM
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Okiedawn OK Zone 7

Often, the first sign is yellowing leaves on your squash plants or wilt. It isn't the general 'heat stress' wilt you often see on hot days.

With heat stress wilt, your leaves usually stay green despite mid-day wilting, and they perk up in the evening as the sun sinks low in the western sky and the temperatures begin to drop.

With squash vine borer wilt, the leaves often go from good healthy green color to yellowish-green uneven color at the same time the wilting occurs. Sometimes the leaves perk up a little in the evening, but their color doesn't recover, they don't fully recover and they just keeping looking worse every day. Often, they are dead within days.

Sometimes if you look at the stems down near the base of the plant like Game bird did, you can find the spot in the stem where the squash vine borer larvae tunneled into the stem. Then, using a sharp knife, you slit the stem, remove and destroy the larvae, press the stem back together and pile dirt on top of the slit area. Water it to pack down the soil and help the plant begin recovering. Sometimes you see the spot the larvae tunneled in, sometimes you see the sawdust type stem residue and sometimes you see frass (caterpillar poop). You can have multiple larvae in one stem, or larvae in several of the main stems near the base of the plant.

Some people who spend a lot of time out in the garden will notice the moths when they appear and before they lay eggs, and may be successful in killing them and preventing those moths from laying eggs, but more moths keep coming.

Squash vine borers are a major pest of members of the cucurbit family, although they bother some types more than others.


    Bookmark   July 9, 2009 at 1:06PM
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I wonder if this is what could be going on with my cucumber. It has been my most productive plant in the garden so far but recently, though not suddenly, many of the HUGE mature leaves started turning yellow, the ones at the bottom and even more recently, I a m having leaves just will for no apparent reason. They seem to be perfectly green with no pest but the leaf just turns into a floppy rag. I think I will look for signs of the borer.

DUHRRRR! I've only been watching my "squash" for signs of the borer, because it is a squash vine borer ;)

    Bookmark   July 9, 2009 at 2:06PM
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Here is a flyer from the Department of Entomology, University of Nebraska-Lincoln


Here is a link that might be useful:

    Bookmark   July 9, 2009 at 3:49PM
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SVBs also target pumpkins, but not melons. I'm not sure whether they like cucumbers or not, as I've never grown cukes before this year. (that is, never successfully grown them - powder mildew killed them off in Minnesota when I tried)

It's my feeling that by the time the plant is yellowing, it's likely too late. I look at the base of the stem every couple of days and look for frass, which is their poop or what they've dug out and pushed behind themselves and out the hole they came in through. It looks something like wet sawdust. If I can't see the grub just inside the hole, I feel up and down the stem an inch or so feeling for the stem to be softer. The soft direction is the direction it bored, which is usually "up" (away from the soil). I feel for where the softness ends and go about a half inch above that and stab into the stem and cut about a half inch slit. I twist the knife to see inside a bit if I can. If I stabbed the worm, it's usually a bit juicy (ick!) If the stem is really solid there, then maybe I stabbed too high and I'll go back an inch to the soft area and try again. Then work my way down back to the hole. I've found the grub will often try to back out away from my cutting and sometimes I'll see it in the hole and get it there.

If the borer (or multiple borers) have girdled the stem all around, then it's a goner and just pull it up. Don't forget to do an autopsy to kill any borers inside of it.

A sharp pocketknife or an exacto knife do a good job. I've seen pictures of people using scissors, but I can't see using them and not doing a whole lot of damage to the stem.

SVBs are usually in the stem, but sometimes you'll find them in a leaf stalk and once I found them in a fruit (acorn squash, incidentally).

    Bookmark   July 9, 2009 at 3:59PM
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Okiedawn OK Zone 7

Actually, sometimes--though rarely--SVBs do target both cucumbers and melons. I've had them target my cukes and melons either after all the squash and pumpkin plants are dead, or if I am growing melons and cukes, but not squash, gourds or pumpkins. I think they prefer squash family members, and in particular zucchini and most pumpkins.

Some varieties either are not attractive to SVBs so are shunned by them, or are more resistant to damage from them. In my garden, "Seminole" pumpkin has never shown SVB damage and only rarely have I seen SVBs on Yellow Summer Crookneck, Acorn, Green-Stiped Cushaw, Butternut or Turk's Turban. I also see it only very rarely on gourds.

In our garden, most pumpkins are very susceptible to SVBs, although sometimes you can get around the SVBs with a fall planting of pumpkins. Hubbard squash is very susceptible as well, as is Small Sugar Pie pumpkin.

Although SVBs often get our zucchini plants, they never bother the Cocozelle and Costa Romanesco varieties.

    Bookmark   July 9, 2009 at 4:51PM
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