Author Topic: Help me figure out what's happening to my pumpkin plants?  (Read 517 times)

yodella

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Help me figure out what's happening to my pumpkin plants?
« on: July 14, 2017, 08:57:44 AM »
Hello, I am a novice gardener in the Midwest and I planted a pumpkin patch this spring with 16 plants. The plants are mostly doing well, but I've started to notice two issues:

1. A black, bumpy, mold-type thing growing on some parts of a few plants, and on the surrounding mulch.

2. Strange light spots near the veins in some leaves on 3 or so plants.

I tried spraying the black stuff with a fungicide a couple days ago, but it doesn't seem to have made much of a difference. I've also been using liquid fence to keep away the deer and rabbits, and spraying the leaves with a water/milk solution once a week to guard against powdery mildew. Also, it's been extremely rainy here the last couple of weeks, not sure if that's a factor.

Does anyone have any idea what these two problems are, or how to treat them?

Thank you!


http://imgur.com/9kQTsNo

http://imgur.com/KLC7M7B

http://imgur.com/wbBUyG0

http://imgur.com/18cRTvY

http://imgur.com/lzyzj3e
« Last Edit: July 14, 2017, 09:01:09 AM by yodella »

gardeningandgreen

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Re: Help me figure out what's happening to my pumpkin plants?
« Reply #1 on: July 14, 2017, 09:02:06 AM »
Its kind of hard to see in the pictures but could it be some sort of insect eggs? I would try to keep the area a little dryer if it is some sort of mold or mildew. Possibly moving some of the much out and putting it in a sunny warm area to dry well. Good luck! Garden problems are always fun!

lthenderson

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Re: Help me figure out what's happening to my pumpkin plants?
« Reply #2 on: July 14, 2017, 11:53:27 AM »
I used to raise pumpkins for a living. I would say your last picture is definitely the start of powdery mildew which is quite common among pumpkins. I haven't seen anything like your other pictures before but when something like that happens, I cut a piece of the affected plant and take it to the local agriculture extension office. They generally can tell me what it is and how to treat it. They are a wonderful resource that many don't know about.

yodella

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Re: Help me figure out what's happening to my pumpkin plants?
« Reply #3 on: July 14, 2017, 02:12:38 PM »
Thank you both!

Lthenderson, appreciate the professional advice. I did contact my extension office earlier today and so far it seems to have stumped them - they say they are researching.

As for the powdery mildew, what did you use to control it? I'm leaning toward Neem oil, but am not opposed to chemicals. I will be devastated if it takes over the patch and I don't get any pumpkins. In your opinion, what is the best product to use?

llorona

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Re: Help me figure out what's happening to my pumpkin plants?
« Reply #4 on: July 15, 2017, 01:06:51 AM »
Could those be black aphids?

I've only grown squash, never pumpkins, and my plants have always been susceptible to powdery mildew. I would try using Neem, remembering that you have to keep spraying the plants.

Hotstreak

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Re: Help me figure out what's happening to my pumpkin plants?
« Reply #5 on: July 15, 2017, 09:05:53 PM »
Your first photos looks like a mold or fungus of some kind.  Where did you source your mulch, what is your watering method and schedule, and what is the condition of the mulch and soil when you?  I would water directly on the soil if you're not already, and lengthen the time between watering's so that the mulch & top few inches of soil dry completely.


No PM experience for me, knock on wood, but I believe the standard protocol is to carefully remove any badly infected areas and apply a fungicide to control further outbreaks.  Neem is an all natural fungicide among other things, but may not be as effective as a non-organic chemical option.  I would try it first and see how things go.

yodella

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Re: Help me figure out what's happening to my pumpkin plants?
« Reply #6 on: July 17, 2017, 07:25:03 AM »
Thanks all!

Hotstreak, our mulch was free, from a neighbor who owns a tree service. Pretty sure there was already some kind of mold in it because after spreading it over the patch (~100 wheelbarrows worth), I had a bad cough for two weeks. When we were shoveling it around, little puffs of something that looked like smoke were impossible to avoid.

As far as watering, we haven't had to do much because it's been exceptionally rainy (and humid) for the last 3 weeks or so. Prior to that, we watered with the hose on the soaker setting, at the base of the plants.

Last night I removed the infected leaves and sprayed two plants with Neem oil, as a test. I'll check them tonight and if they look fine, I'll spray the rest of the plants, and we'll see where that gets us.

lthenderson

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Re: Help me figure out what's happening to my pumpkin plants?
« Reply #7 on: July 17, 2017, 09:12:47 AM »
As for the powdery mildew, what did you use to control it? I'm leaning toward Neem oil, but am not opposed to chemicals. I will be devastated if it takes over the patch and I don't get any pumpkins. In your opinion, what is the best product to use?

I grew 10 acres of pumpkins and never saw powdery mildew ever due much harm to yields unless it started early in the spring. Even then the yield reduction wasn't worth the cost of treating 10 acres of pumpkins so I just let it go unchecked. But I have heard Neem oil works well especially if you catch it early.

Roxysmart360

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Re: Help me figure out what's happening to my pumpkin plants?
« Reply #8 on: July 20, 2017, 10:15:11 AM »
I am not sure what the black stuff is in the first few photos, but the last photo is definitely powdery mildew. I have spent a lot of time growing giant pumpkins so I have seen this happen a few times and learned a few lessons.

A couple of questions:

1. What time of day do you water your plants?  You'll want to water them in the AM or early afternoon at latest. This will allow the leaves to dry out and keep the mildew from spreading.
2. Did you get your soil tested? Pumpkin plants do not like low pH soil. It  can affect the mineral uptake of the plant.  You will want to get your soil tested, especially now that you have added all that mulch as it will likely raise the pH of your soil as it breaks down.
3. How are your plants spaced? Powdery mildew hates free circulating air. Space plants out or keep them pruned just to primary and secondary vines to prevent overcrowding in the patch.

Lastly, there are products that can treat mildew (anti-fungicides). The best way to prevent powdery mildew is to have a healthy plant. Water deeply in the AM and ensure that your plants are getting the right nutrients. I have read that plants can be more susceptible to mildew if they are low in calcium. So it might be worth looking into that soil test and either bring up the pH or/and adding calcium.

Hope this helps. Good luck with your patch.

bender

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Re: Help me figure out what's happening to my pumpkin plants?
« Reply #9 on: July 20, 2017, 10:28:22 PM »
The smoke/steam coming off your wood chips is likely a heat reaction from decomposition.  The wood chips would be warm.  I've seen white/grey decomposition steam coming off a pike of wood chips many times.

deborah

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Re: Help me figure out what's happening to my pumpkin plants?
« Reply #10 on: July 20, 2017, 11:31:47 PM »
The second picture is definitely insects - probably aphids (the aphids here are green rather than black, but apart from the colour, they look the same). The first picture looks like detritus - probably poo from something, and some middle bits of the leaves have been chewed - looks like caterpillars. I suspect that the third picture is more of the same. The mulch picture is decomposing mulch. As pumpkins grow in compost bins all the time, this isn't a problem. The last picture is definitely powdery mildew.