Row covers are pointless for SVB control because the flowers require insect pollination. Insects can't pollinate with a row cover on. The SVB moths are flying at the same time the plant need pollination. Unless you want to go out early each morning and hand pollinate you need the insect pollination so forget row covers.

The moth prefers to lay eggs near the base of the plant, but it can lay them anywhere so the pantyhose thing isn't real likely to work out.

Wiping off eggs is OK if you can actually do it, but getting access to the whole vine is often easier said than done.

I have a very simply, elegant solution, but many won't like it. Use a broad spectrum pesticide like pyrethins or rotenone.

*NORMALLY* I would be very reluctant to make such a recomendation, but this is an exception. If the borers make it inside the vine the likelihood is the plant is dead and even if you can save it the yield is certainly affected.

There is no need to apply the pesticide to the leaves or flowers, it only needs to be applied to the main stem. Really, who cares if a SVB bores into a leaf stalk? So the leaf dies and you pull it off and toss it. If the main stem is injured though, the plant is toast. Also, check with your state's extension service to find out how long the threat lasts in your area, in most cases it isn't very long and begins only after plants are well established so no need to use a pesticide before or after the threat is present. There is also no need to ever apply the pesticide to developing fruit.

1. The floating row covers are put in place long before Ma Moth appears to lay the eggs and it stays in place until after she is gone, so as justaguy has already pointed out that makes pollination somewhat difficult, but not immposible.
2. Wrapping the stems with panty hose was suggested as being an alternative to the floating row covers but they do not work because Ma Moth lays the eggs, they hatch, and the larva move to the stem bypassing the panty hose altogether. The panty hose might deter some moths that try to lay eggs on the stem close to the soil line.
3. Wiping the leaves would eliminate any eggs on the leaves by squishing them, but since the larva are not going to eat until they start to bore into the stem putting BTK on the leaves will not help. People that advocate that approach probably think of BTK as a contact poison.
If it is absolutely necessary to use pyrethrin based poisons, since nothing else has worked, that could be okay, but since organic gardeners should be concerned about their, and others, environments it should only be a last resort resource not the first thing you reach for.
Rotenone is no longer an acceptable poison for organic gardeners.
The cocoon looks like a brown or reddish wad of fiber in the soil. There are several species that wrap themselves in cocoons and overwinter in the soil however.

I have one foot out the door but will try to reply later, but here are some egg pics. I quit bothering with trying to combat SVB's organically, only the "biggest guns" in the shed work against them, and those "guns" are expensive ($90-$100 per quart.)

Second best thing is sitting near the plants all day with a flyswatter.

Mark

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Actual size is a little bigger than 1/32".

Thank you all for your information. I like yellow squash and my daughter absolutely loves it, but this is starting to sound like a battle I might want to leave to the expert organic farmers and pay them for their effort...

justaguy2 and kimmsr -- I see the added work that hand-pollinating would add, but I still don't understand why the covers might not prove more of a problem than a solution. The larvae I see would appear to be hatching at different times since they widely range in size from very large to almost too tiny to see. Which would make me think that their mothers hatched at different times and therefore reproduced and laid eggs at different times. If that is true, it would seem possible that the newly-formed adults emerged from the soil at different times. Which would make me very afraid that some might emerge after I placed the covers on the plants -- trapping some adults in with the plants. Not likely?

Thank you Mark for the photos -- discouraging -- I can certainly see why the pantyhose thing wouldn't work. It looks like they lay eggs just about anywhere on the plant. (I'm puzzled by the second photo [the one with the most eggs circled] -- it looks like the eggs were laid on a split stem -- did that happen after the stem was split? (females don't deposit the eggs inside the stems, do they?)

Hmmm. Lots to ponder. I have noticed what appear to be holes slightly bored into the adjacent cucumber plants, but I've sliced into these areas and haven't see evidence of larvae or tunneling; I wonder if they began to bore and decided they didn't like that variety...

I'm trying to gather info on any squash varieties that I could use in a fall planting -- if I planted towards the later side of August (Va. Beach -- near NC border) -- would I avoid these moths altogether? Thanks again. mcaren

Which would make me think that their mothers hatched at different times and therefore reproduced and laid eggs at different times. If that is true, it would seem possible that the newly-formed adults emerged from the soil at different times. Which would make me very afraid that some might emerge after I placed the covers on the plants -- trapping some adults in with the plants. Not likely?

Don't really know. In my neck of the woods I wouldn't worry about it at all. You are a few zones warmer than I though so you may have more SVB generations per year (I have just one).

I have never even thought about SVB moths emerging from the ground under row covers.

The sub-pic with the most circled are of feeder roots an Atlantic Giant pumpkin puts out at each node if buried or touching the soil... the vine was repositioned and the roots got exposed/uncovered... the pic's a little blurry but it goes to show they even laid eggs on the roots!

The top sectional pic, three circled, is a vein/rib on the underside of a leaf. Your question about just sacrificing the leaf: The leaf stem is hollow, they get inside and head downward to the base of the stalk and will try boring into the vine.

Don't believe what you hear about they aim for the first 3 feet of the vine! On an AG pumpkin, I've even found eggs on the yet-to-unfurl ends of vines at 20+ feet from the stump. The new growth with all the "to-be" vines at the end is "tender vittles" to them--softer & easier to bore into. And the leaf underside vein/rib [on that AG pumpkin] was about 24-30" above the ground. The right sectional pic with 1 egg on the stalk was up about 5-6 inches from the ground.

There are maybe 2 possible ways to use the floating row cover successfully.

1. Use a plastic or heavy fabric weed barrier over the ground with the hole for the plant relatively small and in a different area than previous years PLUS use a floating row cover or screen over the plant, completely sealed along the edges, and hand pollinate when flowers are seen and immediately recover/reseal. The weed barrier would prevent them from emerging from the soil under the row cover, and if the stump hole or slit in the weed barrier is small and in a different location they may never find the opening--kinda like a person falling thru the ice in a lake and getting disoriented where the hole is if a current moves you further away.

2. Maybe silly or too much work would be to use row cover cut into long strips (like a roll of it 3-5" wide) and wrap it around the vine as it grows, kinda like you'd wrap electrical tape around a wire or wiring harness, always overlapping. You can do this on leaf stalks too, but it all seems like too much work, plus may constrict the plant's growth as the vine thickens. In theory, doesn't sound bad, but in reality, nearly impossible to do.

Others say use tin foil and just form it around the vine. I don't think any kind of direct contact cloth or foil is really practical--they may just move to a different part of the plant not covered completely.

AG growers often cover the vines with soil about an inch or more deep... it provides extra rooting areas too..but you still have to worry about exposed stalks & leaves, plus you must insure you're not burying a part of the vine that already has eggs deposited.

Mark

Any new techniques on this? These guys are killing me.

Just wondering if anyone has found good ideas for battling the squash vine borers. I just planted my squash and zucchini for this year, and last year the SVB decimated it all. (link below) Iâm still feeling the sting (last year was my first try at gardening) and would really like to avoid the same thing. I am an organic gardener, but I would consider a pesticide used only on the stem at the time the SVB moths are out. Ya gotta do what ya gotta do.

So, anyone?