by Jennifer Poindexter
Do you raise many vegetables in your garden?
Have you noticed there’s an overlap in diseases between some of your vegetable plants? I’m going to bring you a list of some of the most common diseases which frequent veggie gardens.
I’ll also share what you can do to stay ahead of those problems. By being alert to possible issues, you stand a greater chance at saving your harvest if or when disaster strikes.
Here are the common diseases you should be aware of when raising vegetables in the garden.
1. Bacterial Leaf Spot
As the name might have suggested, bacterial leaf spot is formed by small bacteria which infiltrate the foliage of your plant.
It causes spots on the leaves which, in milder scenarios, causes discoloration. In more extreme cases it can cause death to the leaves.
This disease spreads in cold or wet conditions. If you water overhead and soil splashes on the leaves, it can splash the bacteria in the soil onto the plant spreading it to the leaves.
If you don’t clean your garden out over the winter, the bacteria can overwinter in any weeds or plants left in your garden.
When something new is planted in your garden, the following year, this can bring the issue to light again.
Solution:
Preventing this disease requires a few simple solutions. First, try to water your plants from beneath to avoid splashing soil on them.
You should also try to water earlier in the day. This way, if any bacteria from the soil does splash onto your plant, you aren’t also providing a wonderful breeding ground.
By watering early, it allows your plants to dry out before the cool night air hits. If you water later in the day, you’re providing both moisture and cool temperatures which causes the bacteria to spread.
Make sure you clean out your garden each year. Don’t leave any remaining weeds or dead plants in the grow space, as this serves as a home for many pests and diseases.
Finally, if you have bacterial leaf spot growing on your plant, treat it with a fungicide. This should offer the greatest chance at saving your plants from this disease. Then follow the steps to prevent further spread of this disease in your vegetable garden.
2. Rust
The name rust gives an accurate description of what this disease looks like. It will cause discoloration in the foliage of your plant to where it looks as though rust is growing on it.
This is a fungal disease which spreads by wind in wet conditions. The spores will land on the foliage of plants and begin breeding.
Some of the vegetables most commonly impacted by this disease are eggplant, onions, okra, artichokes, sweet potatoes, asparagus, beans, peas, and corn.
Solution:
The best way to stay ahead of rust is to plan ahead. This begins when planting your crops. Ensure you practice proper thinning techniques to avoid overcrowding.
By planting with proper spacing, you increase airflow around your crops. Better airflow lessens moisture being held within the plant and makes your plant less of an appropriate breeding ground for the disease.
You should also try to water plants from beneath or water earlier in the day. This provides an opportunity for plants to remain dry which, again, makes your plant less of a breeding ground for the disease.
Be sure to also practice good gardening maintenance. Clean up the garden area, at the end of each grow season, to reduce ways for diseases to hide in your garden over the winter.
If your plants have become infected by rust, begin treatment by removing any damaged foliage. Treat the rest of the plant with a fungicide that states it’s meant to treat rust. Then follow the above preventative steps to reduce the chances of another outbreak.
3. Downy Mildew
Downy mildew is also a fungal disease. Like most fungal diseases, downy mildew likes damp and cold conditions.
It’s spread via the air and through water splashing soil onto plants, your hands, and your tools. The disease begins with leaf discoloration.
As it spreads, downy mildew will eventually form grey hair that will invade your plant and kill off the leaves.
Solution:
Downy mildew can be prevented by watering your plants from beneath via soaker hoses. You can also water earlier in the day, to give the plants time to dry, prior to the temperatures dropping at night.
You should also wash your hands and gardening tools anytime you deal with plants that look diseased. Any diseased plants should be pulled up and destroyed to avoid further spread.
If you catch downy mildew early, it can be treated with a fungicide. You may also choose to plant specific varieties of your desired crops that are disease-resistant to stand a greater chance at avoiding this disease all together.
4. Early or Late Blight
Blight impacts a variety of vegetables but is most commonly seen in tomatoes, eggplant, and potatoes. Early blight appears as dark spots around the soil level of the plant. Late blight appears as dark spots on the stem and climbing up towards the foliage of the plant.
This disease can live in the soil over the winter and is most frequently transmitted to the plants during watering, when the soil is splashed onto the plant.
Solution:
To deter blight from visiting your crops, try to clean-up your garden at the end of each season. Dead plants and weeds are great ways to attract all the wrong attention from pests and diseases.
Try to water your plants at soil-level via soaker hoses or at least water earlier in the day to provide ample time for the plants to dry before night temperatures roll in.
If early or late blight have infested your plant, treat immediately with a fungicide. You may need to treat more frequently to keep the disease under control.
When a plant seems too far gone to save, remove and destroy it to stop the spread to other nearby plants.
5. Corn Smut
Corn smut is an interesting disease which can form in your garden. This disease can ravage your corn harvest, but in some cultures, it isn’t considered a negative to raising corn.
In fact, it’s considered a delicacy and is eaten as a filling in quesadillas. Though this fungus is edible, it’s hard to miss because of its unique appearance.
The downside to corn smut in your corn harvest is it can lessen your harvest. This disease causes large growths on any part of the corn plant above the ground.
It can overwinter in the soil and is spread via wind and water. Though, it seems to thrive in dry and hot conditions.
Corn smut is difficult to get rid of because it can live in the soil for up to seven years. It infects plants by taking advantage of any damage which may have previously come to it. Corn smut literally sees an opening and takes it.
Solution:
To avoid corn smut, begin by planting disease-resistant varieties. Try to avoid any damage to your corn crop.
For instance, if you have a pest problem, treat it at the first signs with an insecticide to reduce openings for the fungus to enter the corn.
When fertilizing, use a balanced fertilizer. Too much nitrogen seems to boost this disease. If some of your crops are infected by corn smut, remove and destroy them immediately to avoid further spread.
6. Clubroot
Clubroot disease thrives in acidic soil. It’s a fungal disease which is known for attacking brassica crops. The crops most frequently impacted include broccoli, turnips, cauliflower, cabbage, Brussels sprouts, and radishes.
This disease is usually spotted when the plants appear inhibited. After greater research, the gardener might pull up the plant and notice the crop’s bulky roots. This is a sure sign that your garden has clubroot.
Solution:
The best way to prevent clubroot disease is to raise the pH of your soil. The pH should be no less than 7.0 but can be as high as 8.0.
You can increase your soil’s pH by adding lime to your garden area. Use a soil testing kit to make sure you have the soil at an appropriate level. If clubroot is in your soil, it can live there for as long as two decades.
If your plants are impacted by clubroot disease, they should be removed completely. This includes removing every part of their root system as the disease will continue to spread if left in place.
Be sure to sterilize any garden equipment you use to remove infected plants.
7. Blossom End Rot
My first year raising tomatoes I encountered this disease. I was heartbroken at first because my tomato plants looked great but when they began to produce, the tomatoes had rotten bottoms.
I thought my crop was ruined. Imagine my surprise when I realized this disease is only a sign of a calcium deficiency and is quite easy to fix.
This disease appears most frequently in tomato and pepper plants. If you spot it in your garden, don’t feel defeated because you can treat it quickly and still get a decent harvest with proper care of your plants.
Solution:
Blossom end rot is a sign of low calcium in your soil. You can prevent it from occurring by sprinkling powdered milk around the base of your plants during planting.
If you skipped this step, or like I was, are new to gardening and didn’t know this disease even existed, it’s not too late.
At the first sign of blossom end rot, sprinkle powdered milk around the base of your plants. It’s cost-efficient and should provide the necessary calcium to save your harvest.
8. Mosaic Virus
Mosaic virus is a disease you don’t want to find in your garden. The reason being is the symptoms vary by plant and there isn’t much you can do once it’s there.
This is a viral disease which is commonly spread through crops by the gardener. You’ll touch a plant, not knowing it’s sick, and transfer it to another plant because most of us don’t wash our hands with soap and water between touching our garden plants.
Mosaic virus most commonly impacts beans, corn, celery, cucumbers, spinach, tomatoes, peppers, and potatoes.
It can live in the soil for up to two years and some of the symptoms of this disease include curled foliage, stunted growth, and a reduced harvest.
However, the symptoms of this disease can vary by plant. Some plants infected with mosaic virus may display symptoms which lead gardeners to think it’s another virus completely.
Solution:
If you find out you do have mosaic virus in your soil and impacting your plants, your first step should be to remove and destroy any infected plants.
Your next step should be to sanitize everything which came in contact with the infected plants. This includes your hands, clothing, gardening tools, and even stakes which may have supported the plants.
There’s no chemical treatment for this disease. To avoid the disease moving forward, plant disease-resistant varieties.
9. Verticillium Wilt
Verticillium wilt is a distressing disease to hit your garden. Its symptoms include curled foliage which give way to discoloration and wilting. Finally, it can lead to the death of your plant.
This disease is a fungus which infiltrates your plant through the soil. It travels through the plant’s system and eventually kills it.
The plants which are most commonly impacted by this disease are tomatoes, peppers, eggplants, potatoes, cucumbers, and pumpkins.
Solution:
If your plants have been impacted by verticillium wilt there’s nothing to do but remove and destroy them.
Once destroyed, you aren’t in the clear. You have two options. The first is to plant vegetables which are resistant to this disease.
The other option is to kill the fungus in the soil via solarization. You’ll need to till up the top six inches of soil in your garden area.
Wet the area down with a garden hose and cover it with plastic. Secure the plastic and leave it for at least a month.
During the month, you’ll need warm temperatures and sunshine to heat the soil enough to kill the fungus living in it. At the end of the month, you should have healthy garden soil to try planting again.
10. Damping Off
Damping off is a fungal disease which most commonly impacts young seedlings. It’s when the stems and roots of the seedlings rot.
This fungus thrives in colder and damp environments. It’s important to follow the steps provided below to give your seedlings the best chance at avoiding this disease.
Solution:
Once your seedlings have contracted this disease, there’s no reversing it. Your best bet is to avoid it all together.
You should begin by sanitizing your soil. This will remove any hidden diseases in the soil prior to planting in them.
Do the same with any pots or trays you may be starting seeds in. Be mindful, when starting seeds, to start them at the appropriate depth. If planted too deeply, you’ll overwork them during the germination process. This will put stress on the plant and make it more susceptible to disease.
Also, consider proper spacing during planting. Adequate space will increase airflow around the plant.
It’s wise to water your seedlings from beneath. Set your grow tray or pots in a dish of water. This allows the roots to absorb water without making the seedlings wet.
Provide a grow area with plenty of heat and lighting as well. This is the opposite of what the disease prefers for a breeding ground.
Finally, you can use a natural fungicide to help keep this disease at bay. When your seedlings begin to form, sprinkle a layer of cinnamon on the soil to fight off any unwanted diseases.
This concludes our tour around the vegetable garden of some of the most common diseases you may encounter.
You now know what to look for and how to prevent or treat these diseases. Hopefully this will help your vegetable garden to prosper under your care.
More About Common Disease in the Vegetable Garden
https://extension.umd.edu/hgic/topics/vegetable-diseases
