Three “Genovese-type” sweet basils are resistant to Fusarium wilt: 'Nufar', 'Aroma 1', and 'Aroma 2'. While these cultivars are resistant to Fusarium wilt, they are susceptible to basil downy mildew, another devastating basil disease.
Nufar basil (Ocimum basilicum 'Nufar') is the first variety of sweet basil (O. basilicum) that is resistant to fusarium wilt. Fusarium wilt is a disease that causes sudden wilting and death in multiple species, including basil. It is caused by the fungus Fusarium oxysporum f.
The best management practices include planting disease free basil seed. If you can't get tested seed, soak your seed in cold water for 4-hours and then transfer the seed to a heat treatment of 20 minutes in 133-136° F water.
Basil 'Italian Large Leaf'
Upright, 18-24″ plants are hardier than other Basils.
Managing downy mildew in the home garden
Resistant varieties of basil include Rutgers Devotion DMR, Rutgers Obsession DMR, Rutgers Passion DMR, Rutgers Thunderstruck DMR, Amazel, Prospera Compact DMR (good for container production), and Prospera. Lower disease levels occur in red leaf basil varieties (O.
Pathogen-free seed is most important for plantings not expected to be exposed to wind-dispersed spores, such as greenhouse crops when too cold outdoors for basil to survive. Minimizing leaf wetness and reducing humidity to obtain conditions unfavorable for disease development may suppress downy mildew in greenhouses.
Hosts. Ornamentals are common hosts for downy mildew fungi. Common ornamental hosts include aster (Aster spp.), coreopsis (Coreopsis spp.), rose (Rosa spp.), rudbeckia (Rudbeckia spp.), snapdragon (Antirrhinum), viburnum (Viburnum spp.) and violets (Viola spp.).
One of the easiest and most popular culinary herbs to grow is the common or sweet basil, Ocimum basilicum. A member of the mint family (Lamiaceae), it is native to southern Asia and islands of the South Pacific. This tender annual is popular for its aromatic leaves, used fresh or dried.
Basil grows well next to many plants, but there are a couple of plants to avoid growing near basil. Herbs. While you can plant basil next to chamomile, oregano, and chives, basil generally prefers the company of vegetables over other herbs, and should not be planted near rue or sage.
Genovese basil is the plant name for the most commonly used type of basil in western cooking. Thai sweet basil is quite different in appearance to typical Genovese basil. It has a more solid stem, and thus the herb branches are often sturdier while regular basil is more delicate.
Synthetic fungicides are widely used to control wilt diseases. Thiophanate-methyl was found to be effective against Fusarium wilt disease when applied as a soil drench and a seed dresser3.
How to Control Fusarium Wilt: Once fusarium wilt infects a plant, there is no effective treatment. Remove and dispose of affected plants immediately; don't compost this garden refuse. Whenever possible, remove and replace fusarium-infected garden soil.
The beneficial soil-borne fungus Trichoderma harzianum strain T-22, which is sold as Trianum, can help keep Fusarium at bay. This fungus competes with Fusarium in the soil for nutrients and can even destroy this harmful fungus.
There is no cure for basil Fusarium wilt once symptoms are apparent. Always infected plants should be removed immediately - sporulation on the surface of the dead stem areas can otherwise be splashed to nearby plants or even become airborne.
Resistant plants
Monocotyledonous plants (e.g. grasses, members of the iris family and most bulbs) are generally resistant. Conifers are immune to the disease.
Keep your basil plant healthy and wilt-free by either covering it or by growing it in a container and bringing it indoors on cold nights. Basil can handle heat extremes more easily than cold extremes.
Plants to avoid
Thyme and sage have different growing requirements than basil. Thyme needs drier, sandier soil, and basil needs moist, nutrient-rich soil. Fennel and common rue attract pests that could infect your basil plant and stunt its growth. Plus, common rue can also make basil leaves taste bitter.
Compost soil, coffee grounds, stale beer, tea, or mineral water are all excellent choices. These natural fertilizers provide essential nutrients for your basil, promoting healthy growth and blooming. But remember, moderation is key. Over-composting can lead to nutrient overload, so keep it balanced.
Basil performs best in full sun—that means 6–8 hours of direct sunlight per day—which is necessary for the best possible flavor and fast growth. If you're growing indoors, place the planter in a south or west-facing window. North and east-facing windows just won't cut it!
The best variety to grow for flavor is sweet basil
Sweet basil, specifically a variety of sweet basil called Genovese basil, is the star of the Italian classic, pesto, as well as many other sauces and soups.
Basil prefers moist soil – not too wet and not too dry. You want the soil to be damp, not drenched. Although basil loves warm weather, a hot midday sun can be rather harsh. If you see wilting only during the peak hours for summer temperatures, you may need to add light shade over your basil plant.
For optimal growth, basil plants benefit from a balanced NPK ratio, such as 10-10-10, providing equal parts nitrogen, phosphorus, and potassium. This balanced fertilizer promotes vigorous foliage growth, flower production, and overall plant health.
While some downy mildews survive from year to year locally in plant debris, in the soil, or on weeds, others do not survive in cold climates and must be blown back to our region from southern climates each spring.
Chlorothalonil and mancozeb are the main protectant fungicides for downy mildew. Copper is not as effective.
There is no known cure for basil downy mildew. If you see basil downy mildew, harvest any asymptomatic leaves on infected plants, as well as other healthy basil plants in your garden.