Common diseases you may find in your garden

Water-Borne or Water Spread Diseases

Water carries disease throughout the plant and to other plants. Increasing air-circulation by providing space between plants, proper trimming, and practicing proper water techniques will help. Watering the bottom of plants in the morning, while not getting the leaves wet, for instance, will prevent disease from spreading. Most plant diseases are host-specific, so a disease affecting your tomatoes will not affect your zucchini.

  • Early and Late Blight

Commonly affects tomatoes and potatoes. Early blight affects plants in the spring, late blight is caused by those in summer. It causes leaves to wilt and can cause early moulding or death of fruit. Do not save seeds from infected plants.

  • Powdery Mildew

It looks like dusty white spores that are commonly mistaken for downy mildew, but it’s caused like a fungus. It appears first on the underside of leaves first. It is not fatal to the plant but does stress out the plant, making it susceptible to pests and other infections.

  • Downy Mildew

A microbe, closely related to algae, affects plants that grow on vines including grapes and cruciferous (cabbage, broccoli etc). It mostly reduces leaf surface area, reducing the production of the plant. It is soft and fuzzy that can be white, purple, grey, or brown. It’s hard to control once a plant is infected, so prevention is key. Water from below to prevent plants from getting wet and spreading disease.

  • Rust

You can find rust on garlic, leeks, beans, and tomatoes. It doesn’t impact the plant, it mostly causes leaf drop. It starts as white spots on the underside of leaves and stems, they’ll eventually turn red or red-brown. Pick off affected leaves as soon as you see it.

  • Anthracnose

It’s a fungus that causes dark, sunken lesions on flowers, leaves, and fruits. It affects many different species – vegetable crops, ornamentals, fruit trees, and shrubs. Start with good seeds, and strong seedlings to prevent disease. Practice crop rotation, changing crops about every 4 years or so.

Most of these diseases are not lethal to your crop. Mostly, they reduce the productivity of your plant as they attack leaves and cause them to die off. Prevention is key, once you have any of the diseases, it’s difficult to manage. These diseases are spread by fungi, bacteria, or microbes. You can plant disease-resistant varieties, pull off diseased leaves early before it has a chance to attack the whole plant.

Other Diseases

  • Clubroot

Affects mostly cruciferous (cabbage, Brussel sprouts, broccoli…). It is a pathogen that can spread by introduced plants. Always check the roots of any new seedlings you buy from a store.

The roots look gnarled and twisted. Don’t plant any cruciferous vegetables in the same soil once you have clubroot. You’ll see wilting of the entire plant as the roots are dying. Remove the entire plant and root system as soon as you suspect clubroot, there is no way to save the affected plant.

  • Bacterial Leaf Spot

It is caused by a bacterial pathogen that mostly affects lettuce. It is spread by wet and cool conditions. There is no chemical treatment for leaf spot, so prevention is best. Remove any leaves as soon as you see them and rotate your crops to prevent continued infection.

  • Mosaic Virus

It causes a ‘mottled’ appearance in a variety of plants. In overwinters in perennial weeds and is spread my pests that feed on them. The virus can live in seeds, soil, seedlings, and containers. If you’re worried about the virus, start seeds with fresh seed starting soil, and cleaned pots. There is no treatment, so prevention is key. Choose resistant varieties, and don’t save seeds from an infected plant.

  • Leaf Spot

Is caused by fungal spores spreading in warm, moist air. You’ll notice leaves start to wilt and curl, turn yellow or red. There are different sprays to control the leaf spot. If you choose to use a home remedy, be careful. Do a test spot on a leaf to make sure that you don’t do further damage.

  • Verticillium Wilt

It is caused by a fungal disease that lives in the soil. It affects many different plants. The best prevention to infection is ‘right place right plant’. Stressed out plants are more susceptible to disease or pests. If you notice wilt, rotate your crops as the disease can live in the soil for years. Remove the plant as soon as you see it.

Diseases can live in garden soil. If you see the disease, try to rotate your crops. Many diseases are family-specific, so planting a different crop in the same place should be fine.

Again, if you’re finding you have disease year after year, you can also try and find disease-resistant crops if you have difficulty getting rid of the disease.

Make sure you are choosing the right place for your plant. Plants or crops will survive a lot of conditions, but if it’s not quite right, the plant could be stressed. Stressed plants are more prone or susceptible to disease and pests.