Ginger is susceptible to soil-borne disease.

Ginger plants are most susceptible to soil-borne diseases. You can help prevent this by planting your ginger in fresh, nutrient-rich, disease-free soil. That means using clean, fresh soil and compost that’s free of diseased plant matter. Remember: any time you lose a plant to disease, throw it out. Don’t compost it. You may feel like it’s kind of wasteful. But composting diseased plants just spreads more disease the next time you dip into the compost bin.

Bacterial wilt is a soil-borne and water-borne disease that can take a big toll on the productivity of a ginger plant. Once the soil is infected, it can take a long time before you can plant ginger there again. In Hawaii, where ginger is a lucrative crop, many ginger farmers have lost their ginger harvest to bacterial wilt. It’s caused by the plant-pathogenic bacterium Ralstonia solanacearum. Once it’s in the ground, this bacterium is all but impossible to eradicate.

And so, many ginger growers in Hawaii find themselves farming like nomads, searching for disease-free fields or areas of land where ginger has never grown before. Because this disease can come on so fast and furious, growers tend to be especially careful with their ginger fields, keeping out traffic and visitors. The bacterial wilt pathogen can show up on hands, boots, tools, vehicle tires and farm equipment, water from irrigation systems or natural rainfall, and, of course, infected ginger rhizomes.

To prevent bacterial wilt, make sure your planting soil is clean, and don’t rotate your garden with plants that may carry bacterial wilt and doom your ginger plants.

Something as easy as routinely cleaning your gardening tools can go a long way in preventing the spread of soil-borne diseases. And you can clean the ginger itself before you plant it, using a simple 10% bleach solution (one part bleach to nine parts water) can kill any bacterium on the surface. You can also sterilize the surface of your rhizomes by putting them in an oven at about 122 degrees F for 10 minutes; this technique is also helpful if you find you’ve had nematodes in your soil.

Once the bacterium that causes bacterial wilt is in the soil, it’s time to move on to a crop that can resist it and find a new place to plant and grow ginger—probably above ground, or in sterilized containers.

There are a few other diseases that can afflict ginger: bacterial soft rot, fusarium yellow, and rhizome rot. These mostly develop in hot, wet conditions. If you’re growing ginger beyond its natural growing zones (in a container, in a greenhouse), you may be less likely to see instances of these diseases. If you do, take close-up, clear pictures and contact your local garden nursery or extension center. Never take a sick plant to a garden center or extension center; you run the risk of spreading plant-borne disease.

Spot diseases on your ginger plants sooner so you can treat plants before they are destroyed by disease and can successfully manage symptoms. Here is a three-step approach to keeping vigilant about the presence of ginger plant diseases:

• Research the Risks. Find out about ginger diseases that are prevalent in your geographic area. When possible, buy disease-resistant ginger plant varieties to avoid diseases in the first place—many hybrid ginger varieties have been specifically designed to resist certain diseases.
• Examine Plants Daily. Check your ginger plants every day to be sure no disease symptoms are present or emerging.
• Spot Diseases Early. Catch and treat disease quickly so your plants can recover and thrive.

Ginger diseases can affect the leaves, stems, and rhizomes of the ginger plant. Here is what to look for to spot possible infection:

Ginger leaves—possible disease symptoms:

• rolled and curled leaves earlier than standard end-of-season leaf yellowing
• quick leaf yellowing and necrosis (death; leaves of infected plants turn yellow, then brown, then die

Ginger rhizomes—possible disease symptoms:

• rotten, blackening rhizomes
• water-soaked rhizomes

Ginger stems—possible disease symptoms:

• discoloration of stems
• water-soaked appearance of stems
• soft rot of stems

Ginger plant—possible disease symptoms:

• poorly-growing, stunted plant
• rapid plant decline and death

Preventive measures to avoid ginger plant diseases

The best treatment of plant disease is prevention. Follow these guidelines to avoid some basic planting pitfalls.

Site Selection
Make sure you choose a site (including raised beds and containers) that have no history of previous ginger cultivation. If you’ve been rotating your crops, you know that some plants should not go into soil where certain other plants have grown before; the same is true with ginger. Don’t plant ginger in soil where tomatoes, peppers, or eggplant have grown before. Those plants may have built up bacterial wilt in the soil.

Also, make sure you don’t plant your ginger downstream of any land where the above-listed plants grow or have grown, or where previous crops of ginger have grown.

 Improve your soil composition
Before planting your ginger, make sure the soil has a good amount of compost to improve the soil. Some ginger growers use as much as 75% compost when they plant their ginger. Just make sure the compost you use is well broken down and free of pests and diseased plant matter. Remember: never throw diseased plants into your compost; put them in the trash.

For additional aeration of the soil, add some vermiculite. This will not only aerate the soil, but will also help hold water for the roots. You can apply some fertilizer early, at planting, and again once the sprouts have emerged. But you’ll give your ginger plants the best start by making sure they have a nutritious soil to begin their growing journey. Nutritious soil makes for stronger, more disease-resistant plants.

 Plant disease-resistant ginger varieties

While you can certainly pick up ginger root at the local market or even dollar store, you have no way of knowing whether that rhizome came from soil carrying bacterial wilt. The best way to get a disease-free ginger harvest is to get certified disease-free rhizomes to start with.

 Water your garden properly
Don’t underwater or overwater your ginger plants. By keeping a regular watering schedule, you’ll keep your plants vibrant and healthy. Overwatering and watering directly on the plants—instead of the preferred watering method, directly at the stem on the soil—leads to consistently wet conditions, which allows bacteria, fungi, and viruses to thrive and multiply.

 Destroy infected plants
Throw away or burn infected plants. Don’t keep infected plants over the winter in your garden, and don’t throw them on your compost pile. Disease-ridden plants, even when dead, will spread the disease to other plants or even your soil.

Have you had problems with diseases attacking your ginger plants? What types of problems do you regularly face with your ginger? Please tell us how you treat and prevent diseases from destroying your ginger crop.