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Blight, Mildew, Aphids & Other Garden Pests & Disease Demystified

September 12, 2012
Female Butternut Squash Flower Open & Ready for Pollination

This female butternut squash opened last week. I hand pollinated it, and it is now beginning to mature the fruit despite the late date of the growing season.

This has been one of our worst vegetable gardening years ever for garden pests and disease (and other annoying issues).

How’s that saying go? “If you’re not killing plants, you’re not growing as a gardener.” Something like that anyway, and my apologies for not knowing who to credit. I think I read this first on a magnet on a fellow gardener’s fridge years ago.

There are a number of reasons for our crap year:

I’ve been traveling a lot this growing season, so my timing’s been off and my ability to monitor crops daily hasn’t been possible.

For a number of personal reasons, last fall we didn’t give our soil the careful attendance we have in years past.

Despite our efforts at crop rotation, pests and disease still found their way to many of our crops. It happens.

So we’re rolling with the punches, savoring what we’re actually harvesting, disposing of disease as we see it, and planning to do better next year. We’ve sown some cover crops already and will be pulling soil soon for testing and amending properly over the dormant months.

Here’s a brief photo rundown of the pests, damage and disease we’ve had in over-abundance this edible gardening year.

It all began early this season with the damn cat eating our indoor seedlings. That meant we were behind schedule with our tomato (and other) seedling starts. With a short growing season, that can really make a difference. And, with the spring lasting cool and wet for so long, the earliest flowers our tomatoes formed withered and fell from the plants. It wasn’t until very late in the growing season that the pollinated flowers even started to turn to fruits.

Later, in some of our garden beds, pee weevils did damage to our sugar snap peas, snow peas and fava beans. That meant we didn’t plant any pole or bush beans in those beds in hopes of breaking the pest’s life cycle. It also means we won’t be planting legumes in those beds again next year.

Cabbage worm on Brussels Sprouts engulfed in a spider's web

Cabbage worm on Brussels Sprouts engulfed in a spider’s web

Our bed filled with onions and brassicas (read: broccoli, cabbage, kale & Brussels sprouts) struggled. Part of the reason is poor soil care. Too, my timing on switching from plastic hoop houses to horticultural fleece was late because of my travels; this meant much of the broccoli bolted to seed. And, even with the fleece, the darned cabbage butterflies got to the crops. so we hand picked them like mad. Too, the aphids made their way into the crops as well despite their hatred of onions. Oh well, we tried. The onions turned out fantastic. We got one cabbage. The kale survived & is still producing nicely. And, fortunately, a number of spiders set up shop in the tips of the Brussels Sprouts. Here they devoured aphids all season and have done some damage to the cabbage worms as well!

Looks like we’ll be enjoying kale and Brussels Sprouts well into autumn.

Tomato Blight & Mildew Appearing on Tomato Leaf

Tomato Blight & Mildew Appearing on Tomato Leaf

After enjoying several years with bumper crop tomato harvests, this year breaks our streak. Because I’ve been traveling a lot this spring and summer, I’ve had to make some compromises that lead to an infestation of blight. I haven’t had the diseased plants tested, but all signs point to this being late blight. Not all of our plants have been hit. The ones planted into the ground are doing just fine so far; the ones grown in containers are going down one by one. We’re getting tomatoes but no where near the harvest of years past.

The container grown tomatoes are our most stressed plants. In years past, they’ve done okay in pots. I’ve monitored them daily and been very careful with watering. This year, because I had to travel quite often, I made the decision to try placing trays under the tomato containers. I knew that leaving them in standing water could lead to disease issues, but I also knew that letting them dry out completely for a couple of hot days would most certainly lead to their demise. So the trays it was, and now I’m paying the price.

Tomato Blight Spots on Tomato Stem

Tomato Blight Spots on Tomato Stem. We tossed this plant last week; that big heirloom tomato in the background is now almost ripe on the kitchen counter!

The good news is that quite a bit of the fruit from the diseased plants is still ripening indoors. I simply place the green fruits near actual ripe tomatoes, and that seems to be pushing the green ones toward red. The plants and the soil they’ve been grown in are going into the waste bin — not our compost where the disease would happily rest overwinter and reappear next spring.

Blight is everywhere. If you’ve got it, do yourself and your neighboring gardeners a favor and dispose of it fast! Don’t compost it. Don’t let the plants sit outside where the spores can travel and infect other plants. Get rid of them, and do it fast!

Oh, and one more note: the blight likes all the tomatoes in our garden. It doesn’t discriminate. Cherries, fat slicers, paste tomatoes…they’re all at risk. And so are potatoes. Yep, the minute the tomatoes started looking bad, I dug all our remaining potatoes before the blight could travel to them. So far, our eggplants and peppers are still growing strong. But all these nightshades are at risk when a disease that favors them enters the garden.

Powdery Mildew Infecting a Patty Pan Squash

Powdery Mildew Infecting a Patty Pan Squash

And, of course, September has arrived and with it comes powdery mildew. This disease favors hot, dry weather, and it has gone gangbusters all over our zucchini, cucumbers, patty pan and butternut squash plants. All of the zucchini plants are long since removed from the garden and greenhouse. Most of the cucumbers are pulled as well, though a couple of plants are still doing fine. Too, most of our patty pan are battling the disease. And, our late-planted butternuts are still doing okay.

In years past, we’ve tried baking soda sprays to beat back powdery mildew, but mostly that really didn’t do much, and using that spray bottle day in and out on all those big leaves (upper side and under side) left me with very sore hands. Our next control method is to cut out infected leaves. This works fairly well if you can do it everyday at least once a day. With all my travels this year, that just wasn’t going to happen. So, the garden suffered.

Too, our timing on planting squash was a little late this year. So, our butternuts have just recently put on a few late fruits. Since these can withstand a freeze and since our summer weather is still warm, there’s hope we’ll get a few from our harvest. So, I’ve been out there with my eyeshadow brush each morning, hand pollinating every female flower I can find. A few are starting to mature the fruit, so maybe…just maybe…there’s hope.


  1. nichole says:

    ha ha. you went to my garden.

    I had:

    early blight
    late blight
    powdery mildew
    squash rot
    Japanese beetles
    flea beetles
    cabbage moths
    cabbage worms
    stunted collards
    stunted garlic
    spider mites
    and thousands of aphids

    ah the joys of organic gardening. SUX

    I did have success spraying milk on my powdery mildew it totally works. I used iron oxide for my slugs that works too.

    soap spray didn’t really for aphids work or maybe it did but I was too late
    everything else i’m at a loss.

  2. nichole says:

    p.s. you don’t have to dig up blighted tomatoes, if you catch it early you can spray with baking soda according to the gardening by the yard dude. look up his recipe good luck

  3. nichole says:

    try the 1% milk on your powdery mildew it works. spray every few days.

  4. Nichole, we’ve approved your comment and accept it as your own. However, we don’t agree with your proposal that baking soda sprays will beat back tomato blight. If you would like to share the scientific source that proves this, we’re eager to read it.

  5. Nicole, thanks for your comment. We have heard mixed reviews of the milk spray technique. Frankly, for the cost of the milk and the cost of labor AND the mixed results, we aren’t big on this. Glad it works for you though.

  6. Carole says:

    Can cabbages and brocolli leaves get blight? There are brown patches appearing on the leaves. They are only bby plants. I have a picture I can send

  7. Carole, Thanks for your inquiry. Brassicas are susceptible to any number of pests and diseases including bacterial blight and other leaf spot issues. It is near impossible to fully diagnose any issue with only a photograph. If possible, try taking a sample to a local nursery, horticultural extension agent or Master Gardener or bring in a local consultant in your area for help.

  8. Nichole says:

    if you want “scientific evidence” about the baking soda spray for blighted tomatoes, please ask the “GARDENING BY THE YARD” guy on his show. if you read my post, I attributed this remedy to him, I didn’t make it up myself so asking me for scientific evidence of it is kinda dumb.

  9. Nichole, we have approved your comment above despite your nasty tone. Our position is that no question is “dumb” and together we can all grow as gardeners by lifting each other up and providing support, encouragement and empowerment. In asking for any scientific evidence, we were offering you the opportunity to share the background on what you had learned that prompted you to share the methodology you were putting forth. We in no way encourage anyone to take any advice at face value — televised or otherwise. Best of luck.

  10. Chris says:

    I had tomato blight and I pulled up the plants, but am now wondering if my soil is affected?

  11. Chris, you may very well have a residual issue. If you were growing in containers, you may wish to dispose of the potting soil. If you were growing in the ground, crop rotation may be a good solution. Planting tomatoes or other nightshades in that spot is probably not your best bet. Good luck!

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