squash had wilt & powdery mildew, how to prepare for next year?

homebody_2007

15 years ago

Hi all,

Thanks for all your help in an earlier post about cucumber beetles!

I'm thinking about next year's garden, and how I should handle the fact that I had a lot of cucumber beetles -- the cuke plants and a few squash plants wilted & died quickly (I'm thinking bacteria wilt), and later some weakened plants develop powdery whitish spots (powdery mildew?) Some squash plants (including winter) survived & produced pretty well.

I treated once with Sevin for the beetles, but after suspecting I killed a lot of honey bees, decided not to use it again.

My tomatoes & beans are fine. I have seen quite a few white aphid looking creatures, but they seem happy with dead or dying squash plants.

My questions are: How should I plan next year's garden, thinking I've got bacteria in the soil where the squash was? Will powdery mildew (if that's what it is) affect anything next year?

Thanks for any ideas on this!

J House

Lebanon, Ohio

Sort by:Oldest

Comments (4)

solanaceae
15 years ago
10-30% solution of milk to water seems to have good reviews as an anti fungal agent. I did finally get drier weather but some of my plants seemed to overcome the issue after I used this as a foliage spray.
I did use pyretherins for something that was bothering my squash. I stayed away from the flowers and used it in the evening when the pollinators were not active. It breaks down with sunlight.
zeedman Zone 5 Wisconsin
15 years ago
Homebody, your suspicion about bacterial wilt is probably correct, if you have cucumber beetle problems. You should also inspect the stem of any dying squash vines, to see if squash vine borers are responsible. If you find their larvae, or the holes left by them, then prevention next year is your best hope for success.

And if your "white aphid looking creatures" look like this, then you should try to kill them before they reach adulthood. The symptoms of squash bug infestation can appear very much like bacterial wilt.

Butternut squashes (Cucurbita moschata) are more resistant to beetles & borers than C. pepo (pumpkins & summer squashes) and C. maxima (buttercup, hubbard, banana squash). I quit growing zucchini for that reason, and now grow Tromboncino (a butternut relative) instead. It has few problems... but it does take up a bit of space, unless trellised.

You can protect young squash plants with floating row cover, until they either blossom, or outgrow it. This gives the plants time to build up strength, so they have a fighting chance. For me, this prevents SVB, and by delaying the start of attack, reduces the population of cucumber beetles & squash bugs. I could not grow most winter squash successfully without the use of row covers - I highly recommend their use.

The use of nylons or some other impenetrable wrap (around the base of the squash stem) can prevent the SVB moth from laying their eggs there. Also, try to grow squash varieties that root at the nodes; bury the stems early, to encourage early rooting... this will help the plants to survive, if SVB does kill the main stem.

The last thing that you should do (after killing the squash bug nymphs) is to eliminate any pests that might otherwise over-winter. SVB pupae lay dormant underground, so a Fall tilling will kill many of them. Cleaning up any debris in or near the garden will help to reduce the population of squash bugs the following year.
Related Discussions
Winter care of roses with powdery mildew problems
Q
Comments (5)
I've grown Jeanne La Joie for years and years and never had a powdery mildew problem with her. Blackspot definitely just not PM. Since PM is a definite problem on some of my roses I know that it's not just my climate. I suspect that the difference may be location. Jeanne La Joie is located along a fence in a windy site where air circulation is no problem. Also "dry feet" on a rose can help contribute to PM, so always make sure that your roses are well watered. As to picking off each and every leaf of roses prone to PM it sounds good, but most of us have a life. Your best offense is a good defense. For PM the Triflorene found in Ortho's Fungunex (sold now as Ortho's Rose Pride) gives very good protection against PM. But you must have it in place as soon as conditions are ripe and even before the leaves have fully leafed out. As soon as the day time temperature hits 68-70 degrees in spring start spraying per label instructions. Fungunex is also good for preventing blackspot if you have that. You might want to add a layer of bark mulch in early spring under the roses to cover up any leaves which may have fallen during winter and are harboring disease. Once PM strikes there really isn't any effective way to cure it. Preventative spraying will not return the affected leaves back to looking good, but will prevent new infection. Now you can spray with any material you like. But if it isn't doing the job then what's the point. I used the Cornell forumla years before and it not only wasn't effective on some of my roses, it actually harmed others. But then we have a long growing season with lots of time for disease to take hold....As for Thrips, I've found nothing effective against them that I didn't consider too toxic. They are cyclical, so some years are worse then others. Personally I've gotten rid of those roses that suffered severe Thrips damage every year and just live with the occasional damage on my other roses.
...See More
Powdery Mildew -- an answer for after-the-fact!
Q
Comments (20)
I'm one of those commercial growers who got baptised on the powderly mildew issue with a lot of dollars at stake. My first outbreak was on poinsettias. I recognised it immediately before the powdery stage began and called my extension agent to come confirm my suspicions. He didn't think it was. Well, the whole crop bloomed with white leaves, and the aggravation and lost sales were very real. So, even the "experts" can learn a few things. A lot of liner stock had been shipped out that year already innoculated and infected but just not in readily visible stages yet..... and in the next few years where good control was not given to the stock plants WHEN it was needed. You do not cure powdery mildew. You have to work at preventing it. Jean was entirely accurate in her follow-up. Those spores are everywhere, all the time. The biggest thing you can do to prevent large outbreaks of it are to be proactive. Copper used to be used for this condition but it's not friendly to the environment, and not a thing home gardeners would really want to tackle. Even that won't clean up a crop. Some greenhouse film manufacturers are trying to design films to transmit light in just certain controlled wavelengths of the spectrum, because that is how much PM is affected by the environment. The light conditions have to be just right, as does the temperatures and the humidity. So far, this new new tool has not been successful, because plastics degrade and the spectrum of light they transmit changes with age. The baking soda reports have been around a long time, mostly since that big poinsettia outbreak hit the industry. It was concern from the commercial growers who prompted most of the research on ways to control this economic demon. Most of the time, for outdoor plants like lilac........control is just not even important, save trying to give them adequate ventilation. The next year, if the weather is different, then you may not even have an outbreak. We haven't had PM common on poinsettias for many years, but just the word strikes fear in my heart. LOL. I can relate. Just don't put too much stock in baking soda curing it after the fact.
...See More
whitefly??? Powdery mildew??? Why is nothing working??
Q
Comments (8)
Before I offer a bit of info, let me mention that when posting you would better help folks to assist you if you add your zone & geographic area (city or town would be good, along with the state, of course). Your "My Page" listing of "United States" is of no help whatsoever. Don't worry, we will not stalk you. :-) It's powdery mildew on the cucurbits in the first two photos. This has been of epidemic proportions in a large part of the Midwest, in my garden and from what I hear from friends and correspondents in MI, PA and here in OH. Looks like some sort of leaf miners in the last couple pictures, and blight on the tomatoes. Check the links in this earier GW post regarding tomato troubles, linked below. As for the powdery mildew, here is some info from Ohio State: POWDERY MILDEW DISEASES. Many plants are affected by powdery mildew diseases, with different powdery mildew fungi causing the disease on different plants. The most familiar way to recognize powdery mildew diseases is the actual "sign" of the powdery mildew fungus growing on the upper leaf surface. This powdery growth is a combination of asexual spores of powdery mildew fungi in combination with threadlike strands of the fungus called hyphae. The mass of this powdery mildew fungal tissue is visible to the naked eye, but individual spores and fungal hyphae are not; these forms of the fungus, capable of causing infection, are microscopic in size. One of the overwintering forms of the fungus are dark-colored fruiting bodies know as cleistothecia, that are visible as small round objects on leaves, resembling grains of pepper. "Symptoms" (effects on plants from infections) of powdery mildew diseases are sometimes not recognized as being caused by powdery mildew fungi. On a plant like lilac, often symptoms are not apparent - all you see is the powdery white sign of the pathogen. Control involves improving air movement and reducing high relative humidity, to the extent possible, with judicious pruning and plant siting and use of powdery-mildew resistant varieties when available. Also recognize that in many cases the disease causes little harm to plant health, though fungicides may be used when necessary. Common powdery mildew fungicides include: triforine (e.g. Funginex), thiophanate-methyl (e.g. Cleary's 3336), and propiconazole (e.g. Banner). Read and follow the fungicide label carefully when applying to a particular plant. Powdery mildew fungicides can be very effective because the fungal infection by powdery mildew fungi is very superficial compared to most fungal infections, with the fungus only penetrating into the epidermal layer of cells. There are organic preventives (biofungicides) for powdery mildew, too, but as you will read, most, if not all, need to be used before the symptoms develop. See http://www.gardensalive.com/category.asp?c=15 Hope this has been helpful. Here is a link that might be useful: Identifying tomato problems
...See More
Powdery Mildew - my organic experience
Q
Comments (4)
rhizo: Housekeeping, as in, removing diseased dying leaves? I have been for pumpkins, not so much for my cucurbits because they are very dense. I remove what I can, but there are some dead leaves pretty buried within the vines. I am not sure the cause of the dead leaves (is there a natural amount of leaves that die on a vine from "natural" (i.e., non disease/pest) causes? I'm going to post another problem today with photos. Some of my butternut squash leaves are VERY chlorotic, and some dying, and I can't tell the cause, as others are healthy and green. (I don't think it's PM, but who knows?) I look forward to your expertise(s). rhizo ... if there's something else I'm missing as far as "housekeeping" is concerned, please let me know! :) Thanks for taking the time to be concerned and answer. -Veronica
...See More
lorna-organic
15 years ago
If squash leaves stay wet for any period of time, they are likely to develop powdery mildew. Ground watering helps to prevent powdery mildew.

Lorna
homebody_2007
Original Author
15 years ago
thanks all!

Well, zeedman, after checking out your link, I do in fact have a whopping population of squash bugs. Possibly I had both bacteria wilt & certainly the infestation! I must've had some tough squash plants, because I still got too many summer squash, & the butternut & cantaloupe hung right in there.

I'll check my stems for SVB -- the way my pests have been,probably got those too ;-)

Thanks for the suggestion to cultivate -- I might consider skipping a year of squash also -- give those suckers a chance to die!

thanks again.

squash had wilt & powdery mildew, how to prepare for next year?

Comments (4)

solanaceae

zeedman Zone 5 Wisconsin

Related Discussions

lorna-organic

homebody_2007
Original Author

COMPANY

BUSINESS SERVICES

GET HELP

CONNECT WITH US

squash had wilt & powdery mildew, how to prepare for next year?

Comments (4)

solanaceae

zeedman Zone 5 Wisconsin

Related Discussions

lorna-organic

homebody_2007Original Author

COMPANY

BUSINESS SERVICES

GET HELP

CONNECT WITH US

homebody_2007
Original Author