Gladiolus plants grow from corms and often are planted in masses, adding upright color to beds and borders in the landscape. If the corms of your unplanted glads appear discolored and unhealthy, they may be infected with gladiolus fusarium rot. Let’s look at fusarium wilt and rot to see if your corms can be saved.
Glads with Fusarium Wilt
Fusarium of gladiolus is a fungus that can damage the corms you’ve stored for the winter. Spots and yellowing are the first signs of problems, turning to larger discolored areas and lesions. These eventually turn to brownish or blackish dry rot. Roots are damaged or have disappeared. Discard these.
Others stored with them should be treated. Planting glads with fusarium wilt can result in yellowing foliage, sick plants, and no blooms, if they sprout at all. Fusarium wilt results from soilborne Fusarium oxysporum. It affects other corms and bulbs besides gladiolus. Some types of this fungus attack vegetables, some fruits, and some trees.
Symptoms include yellowing and drooping leaves and stunting of the plant. The disease usually starts at the base of the plant and moves upwards. Fungal spores, that may be white to pinkish in color, form in and appear on dying leaves and stems near the soil. These are ready to move with wind, rain, or overhead watering and infect other plants nearby.
While the fungus exists in the soil, without a plant host, temperatures of 75 to 90 degrees F. (24-32 C.) encourage development and provide the perfect environment for spore growth. Fusarium moves into roots or may already exist there. It can spread through plants in the garden as well as the greenhouse.
Fusarium Control on Gladioli
Control in the greenhouse may include steaming the soil or fumigating with a professional product to get rid of the fungus. Drench plants with an approved fungicide. The home gardener should dig up infected plants and dispose of all infected parts, including roots.
If the home gardener wants to continue growing in potentially infected soil, it may be solarized or a fungicide used for treatment. Some fungicides are available for non-licensed gardeners to use. Check for these at your home improvement center.