Kuri Squash problems

[tam91]

This year I tried to grow Kuri squash. They started off great, but gradually got worse, and finally died.

Trying to figure out why... there is a walnut tree in the vicinity, but I believe that I read squash are immune to juglone. Right?

I wondered about the squash vine borer. Read that injecting BT into the stem was the thing to do - we tried that. Made them die faster. Actually, I'm not sure the stem of the Kuri is even hollow - if it isn't, then the borer wasn't the problem, is that right?

Sorry if these are dumb questions, I've never successfully grown any viney thing - cucumbers, melons, and now squash have all died here. Multiple years. In different locations. Aargh.

Any suggestions?

[fortyonenorth]

Red Kuri is a maxima which are, as a group, holllow-stemmed and susceptible to vine borers. When you say "got worse," what do you mean exactly? If the vines wilted, beginning at the main stem, you probably had borers. Here in NW Indiana, the borers reliably hit at the beginning of July.

I've heard of the BT trick, but never tried it. Some say to wrap your stems with aluminum foil "glued" on with a molasses paste - I haven't tried that either. If borers are a problem, I'd suggest growing moschatas.

[tam91]

Hmm, ok, it is hollow. I made my hubby inject the BT, and he said it didn't feel hollow.

What they did, is the leaves would wilt, then recover. Eventually, everything turned brown and didn't recover. The vines themself didn't visibly wilt - but they were climbing up a fence, and attached, so I doubt I'd easily be able to tell if they did.

There were a bunch of tiny light-colored moths that flew up from the ground at the base of the plants when disturbed - not sure what those were. I put sevin there, and got rid of them - but there were quite a lot of them.

I have seen the aluminum foil method - I'll have to try that next year.

Here's pics of what happened (moth in the last pic) - they were beautiful July 1, these pics are July 31.

[Wi-sunflower]

I grow winter squash commercially for my farm market. Usually 5-8 acres of about 15 varieties.

Red Kuri is a popular variety with chefs here so I do try to grow it every year. But it's a variety that is problem prone. It often is a poor germinator. But the big issue I have is the fact that it's often a poor yielder. I was sold out well over a month ago this year.

Red Kuri is a baby hubbard type but it has a soft thin skin that cooks up edible. Some chefs make a puried soup and put the whole cooked squash, minus the seeds, into the blender.

Another variety that is much easier to grow and is a good yielder is Orange Magic. Size and shape is similar. It's earlier too. The flesh is very nice and it's sweet. The big dif tho is that the skin is hard and cooks up sharp so you can't put the skin in the soup.

The other problem is that it seems that the variety is being dropped as I only found it at a company called Osbourn seed. It's bred or grown (not sure which or both) by "Seeds by Design". It used to be more widely offered a few years ago. Oh don't believe the description that it's a "bush" or compact vine. It will grow 20 feet for me some years.

~~~~~~~~~~

From your pics I'm not sure what the problem is as we grow letting the plants sprawl over the fields. Often hubbard varieties will send out adventitious roots from leaf nodes when on the ground and that will make them somewhat imune to the borers.

The one pic it looks like you might have a bit of a lack of nitrogen. Don't quote me on that tho as other things can look like that too. Late in the season Mildew will usually kill the plants but the early fruit will still mature OK. But I don't see any of the white on the leaves of your plants.

Sorry I'm not more help.

Carol

[tam91]

Thanks Carol, that's a lot of help. A friend actually saves the seed, and gave me some. I still have plenty, so I want to try again next year.

Lack of nitrogen - well anything's possible. I didn't fertilize them a lot. However, the soil is very rich here - never been farmed. The only thing I ever grew in that location was runnner beans for a couple years. Tilled mushroom compost in last year. Plus, I put some mushroom compost in this year when I planted them. Are they really heavy feeders? Should I have been fertilizing them a lot, with....?

My friend who gave them to me said they grew very long - theirs climb too, and the husband is often harvesting squash out of trees!

It can't be the walnut tree right? They are ok with juglone?

[fortyonenorth]

I don't think the walnut trees are your issue. I think you have vine borers. The moth in your photo is not the culprit - SVB are black and orange - Google them and you'll see they are very distinct. They were probably very advanced when you injected Bt - hence the appearance the Bt made things worse. It wasn't the Bt, just the damage had been done.

Carol - I think Johnny's listed Red Kuri last year. If not, look around for potimarron - I've never had a problem finding it and it's very similar in taste and appearance.

[Wi-sunflower]

I just mentioned the nitrogen because of the pic with all the yellowing in the leaf. But other things can cause that too.

Hubby does the fertilizer and spraying here so while I will tell him about anything that looks like a problem, he usually takes care of it. He does often tend to fertilize on the heavy side tho. Often too heavy early for our tomatoes.

I don't know about the juglone as we don't have any walnuts anywhere near our farm that I know of.

If you got all the rain that went south of us this year tho, fertilizer and or lack of oxygen (waterlogging) in the soil could have been a contributor to the problem.

We lucked out in that we had our squash on our sand hill this year in part because that was the area dry enough to plant. Enough rain for the early growth but then dry when the squash needed to mature.

We had some of the Orange Magic climb up an old pear tree a few years ago and yes we had mature squash in the tree.

Carol

[Wi-sunflower]

Finding Red Kuri isn't my problem, it's finding the Orange Magic.

I did grow Potimarron a couple of years ago and it's OK but not quite the same as the Red Kuri as far as the chefs are concerned. The skin is not quite as soft.

Carol

[tam91]

I'll just have to try again I guess, and try to prevent the vine borer.

Can you do the BT prophylactially, i.e. early on before the borers come?

I don't think we were waterlogged, I'm on a slight slope, and usually that doesn't happen. Could be possible of course.

[fortyonenorth]

Bt only works on the larvae, so it won't prevent the adult moth from laying eggs. I know some who use row covers to prevent the moths from laying eggs. The timing is tricky, though, because the covers have to be removed when the female flowers begin to emerge.

If you're intent on growing maximas, I would suggest rotating your squash crop every year and make sure you clean up all the plant debris at the end of the season - don't incorporate it into the soil. That'll cut down on the number of SVB that over winter.

[tam91]

I've thought of row covers, but as they're climbing a fence, that would be hard. Does sevin work? If I put it at the bottom of the plant - the flowers/bees are higher up...

I did pull the vines out. I tried cucumbers and melons a few years ago, in a different spot. Then nothing. Then these squash this year, none ever before. So if it's the SVB, I haven't been the one breeding them (at least not yet).

I'll bear those suggestions in mind in the future.

[tjg911]

i agree that is not a squash vine borer and i think your problem is the svb. as stated, kuri have hollow stems and i doubt you could inject bt into a solid stem variety like butternut as those stems are hard. but there'd be no reason to as svb can't get into solid stemmed varieties.

anyway here's what i do and it should work for you. you have to get thru the svb egg laying cycle. i'm in nw ct and i'd suspect you are probably at a similar latitude and therefore your svb are doing the same thing as mine based upon the calendar. i used to have problems with yellow and green summer squash until i learned about starting my seeds later (june 21 vs may 10) and putting the plants out on july 4th NOT before the 4th. by that date the svb has laid it's eggs and has died. so by doing this i have healthy summer squash plants until they die in the fall.

now for winter squash you can't wait that long to set out plants. this year i tried delicata but i knew the svb would kill them. i covered the plants with a floating row cover and kept it on until july 4th. you need a lot of space cuz by 7/4 the plant is really cramped but it worked. the plants grew fine despite being confined in the frc as i planted them out on memorial day weekend, that's 5 weeks under cover. so now i can grow any hollow stemmed winter squashes i want to try as long as i cover them and keep them covered until july 4th! up to this year any variety of winter squash i grew died unless it was a solid stemmed variety (cucurbita moschata). don't worry about them climbing the fences once uncovered they'll do it.

try the frc and your squashes will be safe from the svb.

tom

[tam91]

Thanks. If I'm growing them along the fence, I'd have to be pretty creative with a cover I think. How determined are the SVB? Do the covers have to be basically sealed to the ground?

[Tormato]

tam91,

In my first year of gardening, I had problems with cukes, melons, and squash.

Delicate roots are what cukes, melons, and squash have in common. Not disturbing the roots, if transplanting, helps. Also, amending a heavy soil with lots of compost does wonders.

Tormato

[tjg911]

Originally Posted by tam91

Thanks. If I'm growing them along the fence, I'd have to be pretty creative with a cover I think. How determined are the SVB? Do the covers have to be basically sealed to the ground?

yes you must seal the frc to the ground. i use ground staples. this is why i suggested a large piece of frc. i used a smallish piece and it was very tight by 7/4. however, next year i'll cut an 8' piece off my roll (i'm pretty sure it is 8' wide if not it's 6') and that'll be plenty. you can bury the edges with soil vs ground staples or maybe lay 2X4's on the frc but you need to seal it off. it's a hassle but it works. i refuse to use pesticides so i'm willing to do the work.

tom