Squash...will mulch harbor borers?

[Brown Thumbs]

We never mulched our squash and typically did ok, until it got real hot and dry come July. I tried mulching it with grass clippings one year and we had vine borer problems. This year I'm using aged pine straw around tomatoes, peppers, and okra, but I'm hesitant to put anything around my squash. Would it attract and provide a place for bugs to live (in or underneath) and then make my plants more susceptible to damage?

[rainbowgardener]

The mulch will not harbor borers. The adult squash vine borer is a moth which flies around. The female comes and lays her eggs at the base of the stem of the squash plant. As soon as the larvae hatch from the eggs, they immediately tunnel in to the stem and chew their way around inside the stem, often killing the plant in the process. Once they are ready to pupate, they emerge and burrow into the soil and spin a cocoon. They over-winter in the soil. So at no stage of their life cycle would they be hanging around above ground but not inside the plant.

However, squash bugs do like to hang out in mulch. They are not quite as destructive a pest, but still quite a nuisance and very damaging.

[Brown Thumbs]

Maybe that's the one I was thinking about then. One plant is already showing signs of damage, but I'm not sure from what. Which bug would do this? It was ok two days ago.

[Lindsaylew82]

I. Hate. Squash bugs..... And I get them every year. Lots of them. Here is my regimen.

I spray with neem oil. This helps with 2 things. It's anti fungal (think powdery mildew) and it disrupts squash bug reproductive cycle.

I spray my squash during peak season twice weekly in the late afternoon when the sun starts going down. For several reasons. The main reasons, Squash bugs like to come out at night, and they REALLY don't like to get wet. They will climb up to the upper canopy of leaves, where you can very easily pick them off and toss them in a cup of soapy water, or you can stomp them. The Resident Man crushes them with his fingers...(grossest thing ever...)

If you turn over the leaves, you will find bronze colored egg clusters. I roll them off into my soap water cup. The nymphs go through stages and look very different from stage to stage. Crush them if you see them.

You don't want to spray neem oil during the day when the sun is up. It will burn your plants.

Mulch does help them hide. But I feel like the mulch does a lot more beneficial things that outweigh the harboring of squash bugs. If you stay on top of them, they tend to be pretty manageable. If you don't, they will very quickly overrun the plants.

Ps... In the fall, the become indiscriminate, and will go for melon, pumpkins, squash, cucumbers.... Have I mentioned how much I hate them???

[rainbowgardener]

What you have in the picture, brown thumbs, is not an insect problem. It is powdery mildew, a fungal disease that squash family plants are very prone to. Take the affected leaves off and trash them (not in compost) and start spraying everything else with fungicide (including undersides of leaves). Organic fungicides include hydrogen peroxide straight from the bottle (which is 3% concentration), diluted milk, baking soda solution. Use them one at a time, not together, but you can rotate them. The plants need to be treated every week or two. All fungicides (even the bad chemical ones) work better as prevention than cure.

Re the SVB's - the eggs are laid singly around the base of the stem, but there would be more than one.



Wiping the stems down regularly to remove the eggs is one way to prevent borer damage, but it requires diligence.

We recently had some one write in to say that they spread tanglefoot (a sticky substance that bugs get caught in) on the first few inches of squash stems and it worked to prevent the borers and reduce the number of squash bugs. I don't know if others have tried it yet, but I hope someone does. I'd love to see confirmation of this! But of course it has to be done BEFORE there are already larvae inside the stems. If you have already seen an egg, you need to inspect very closely for any tiny holes, where one might have bored in. Here's the thread where jiminct describes what s/he does: https://www.helpfulgardener.com/forum/vi ... er#p372223

[rainbowgardener]

One reason the SVB's are so difficult is they protect themselves inside the plant stem. The Sevin will not kill the eggs and probably you cannot catch the larvae to spray them, as they tunnel directly from the egg into the plant. Likewise for squash bugs:

Squash bugs are among the more difficult insects to control. This is in part due to the difficulties of spraying large plants such as squash. But squash bugs are also inherently resistant to most insecticides.

https://www.colostate.edu/Dept/CoopExt/4 ... qshbug.htm And the more indiscriminately people use the poisons the more resistant the bugs get.

The Sevin will however kill honeybees, ladybugs and all kinds of beneficial insects. It is acutely toxic to fish and birds. Earthworms are sensitive to small amounts of carbaryl [Sevin] in soil. In field studies, carbaryl treatment reduced earthworm populations by between 50 and 90 percent. Follow-up studies showed that populations took five to twelve months to recover. It is persistent in the environment and readily leaches through soil to end up in ground water and streams. In a pesticide residue monitoring program it was the tenth most commonly detected pesticide. It was also one of eight pesticides detected in baby food samples.

There are more effective and less harmful things you can do to protect your squash crop, like wiping the stems down and applying tanglefoot. Diatomaceous earth spread around the plant base and base of stem helps against the squash bugs, but probably not the SVB's. DE is really good stuff, effective against a wide range of garden pests, but not a poison and harmless in the environment. Only drawback is that it has to be re-applied after rain.

[Lindsaylew82]

I disagree about the powdery mildew...

But I agree about the rest!

I may try the tanglefoot. I saw the other post about it and I'm intrigued as well.

[Brown Thumbs]

Disagree about the powdery mildew? Gosh, I ran out, removed infected leaves, and sprayed everything with a milk and water mix! Found instructions online calling for 1/4 c milk to 1gal water.

Even noticed some beans with bad looking leaves and thought it had some too. Yep, they got milk and water too!

[rainbowgardener]

Nope, that is definitely not powdery mildew on the bean leaves. The powdery mildew is called that because it has a greyish white, powdery appearance to it. Beans aren't nearly as susceptible to it anyway, although it can happen. The bean leaves possibly just got a bit of sunscald on them, or possibly some kind of sucking insect.

[applestar]

...but... Nice thing about the milk spray is it's generally beneficial but harmless.

I need to start doing all this. I'm falling WAY behind and the weather is going to catch up on me. Sometimes my kids stop drinking milk when they feel like it's getting old -- those are MINE I have a container of iffy plain yogurt too. Time to get spraying.

[n8young]

be careful when mulching around cucumbers. I did straw mulch around mine last year, and it was a perfect hiding place/habitat for cucumber beatles. They ravished my plants, and I got less then half a dozen cukes out of probably a dozen plants.