diseases and pests
Bed Gardening, Container Gardening, Gardening

Common Garden Diseases and Pests

I know it’s happened to you. You go out to the garden to collect tonight’s dinner and you see something off. Maybe your spinach is full of lacy holes that weren’t there yesterday, or your tomatoes suddenly have suspicious looking brown patches. Whatever the symptoms, something’s eating your garden! Summer growing season may be winding down, but that doesn’t mean that our gardens’ are out of the woods yet. Keep reading to find out about common garden diseases and pests and how you can stop them.



Blight is caused by bacteria or fungus that attack the tissues of plants. The microorganism associated with blight prefer cool, damp conditions, so plants that receive lots of light and air flow should be safe. This condition is most likely to affect apples and plants in the nightshade family including potatoes, tomatoes, and peppers.

You’ll know your plant has Early Blight if you start finding dark brown patches on leaves and indented dark patches on stems. Remove as much of the affected area as you can and dispose of the infected material far from the garden. Spray the remaining plants with a solution of baking soda dissolved in water. To make the solution, dissolve 3 tablespoons of soda in one gallon of water with 1 tablespoon of canola, vegetable, or olive oil to help it stick. Late Blight will also show up as dark patches, but the area will appear damp and have molding looking patches. Removed and destroy any plants with Late Blight. The best solution for blight is to plant resistant varieties (or cultivars) and rotate where you put your vegetables from year to year.

diseases and pests

Photo by Scot Nelson/Flickr


Rots tend to predominantly affect trees and woody shrubs, but can affect roots crops as well. Moisture loving bacteria and fungus eat away at the plants roots, until it turns yellow and won’t perk up when watered or fertilized. Prevent rot by planting resistant varieties, making sure that your plants have adequate drainage, and are spaced far enough apart for air to circulate. You can also try applying a sulfur based spray once the rot has set in as a last resort.



Rust only affects a handful of edible species, so you shouldn’t need to worry too much unless you grow apples, asparagus, beans, or sugar cane. This disease is a fungus and will cause infected plants to develop powdery rust colored patches on their leaves. As with the other diseases, plant resistant cultivars and destroy affected plants as soon as possible.



Wilt isn’t just the drooping that occurs when you forget to water your plants for a few days. Lack of watering does cause this condition though. When plants don’t get enough water, microorganisms can attack the part of the plant’s system that moves water throughout its structure. This causes the wilt to become permanent. Plants with wilt will droop, turn yellow, and develop dark spots. To keep wilt at bay, plant resistant cultivars, immediately destroy affected plants, and practice crop rotation.

diseases and pests

Photo by Scot Nelson/Flickr


Nematodes are tiny roundworms that live in garden soil. They pose no danger to humans, but can wreak havoc on your vegetables. They use their sharp teeth to devour plant tissues both inside and out. Nematodes cause weak plants that refuse to grow and look a wilted despite being watered. Use lots of fluffy, organic matter in your garden to help prevent nematodes. Plant resistant cultivars, practice crop rotation, and don’t spread any affected soil. You can also try planting marigolds between susceptible plants, as they repel nematodes.


Powdery mildew

Powdery mildew is one of the conditions you’re most likely to encounter. Fungi causes a dry whitish looking mildew on the surface of the plant’s leaves. Sometimes you can see the tiny black spores as well. The plant’s leaves will eventually shrivel and die. Control powdery mildew by planting vegetables far enough apart to promote air circulation, and destroy affected areas before the spores spread. You can also try spraying bicarbonate soda solution onto the diseased area.

diseases and pests

Photo by Scott Nelson/Flickr

Slugs and Bugs

If you start to see holes appearing on the leaves or stems of your plants, an insect is probably the culprit. Slugs are easy to spot because they leave sticky trails of slime all over the garden. Combat these sticky creature by sprinkling ground egg shells or coffee grounds around your plants. They don’t like crawling over course material. You can also leave small dishes of beer in the garden. Slugs will be attracted and then drown in the liquid.

Other insects can be more difficult to diagnose without seeing them. However, you should look for beetles, caterpillars, worms that look like caterpillars, or small crawling insects. Pick them off your plants where you see them and dispose of them. You may also want to look into created habitats for beneficial insects like ladybugs and preying mantises that prey on pests. Depending on the type and size of the insect, you may also need to set traps or scrape them off of leaves before applying, neem oil, garlic spray, or insecticide soap.

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