Considerations

• The type of control you will use organically to address fungus in your garden or lawn will depend upon what type of fungus problem you are having. What works for one fungus type isn't always going to work for another, as different funguses are caused by different complications (excess water, poor drainage, other funguses, organic debris or vegetation).
  
  

Types

• Some types of organic fungus and gnat control include copper, trichoderma and contans. But other types of organic control focus more on eliminating certain things (excess organic debris, for example) rather than adding something to control fungus and gnats. And still other organic means of controlling these problems focus on crop planning (like crop rotation).
  
  

Copper

• Copper is an organic means of controlling funguses on tomatoes and potatoes like Early Blight, Late Blight (if applied thoroughly and fairly often), and Septoria Leaf Spot (on tomatoes). If your tomatoes are greenhouse tomatoes and they get the fungus Gray Mold, you can use copper on them to treat this condition organically, too, as long as you begin copper application before the plant canopy becomes dense. And copper could be used on Anthracnose fungus (tomatoes) as an organic control, too, but one study showed poor results, according to Cornell University's Cooperative Extension.
  
  

Trichoderma

• Root Shield, which contains Trichoderma, is an organic means of controlling the fungus Black Scurf on potatoes. And Plant Shield (which also contains Trichoderma) can organically address the fungus Early Blight if you would prefer its use to that of copper as an organic treatment method of control.
  
  

Contans

• You can even use one fungus to organically help you control another fungus. Contans, a beneficial fungus scientifically called Coniothyrium minitans, can be used to organically control White Mold on tomatoes, peppers, or eggplants. You normally use this after your plant is infected, but in the case where you know a soil is infected with White Mold prior to planting, you should use it in that soil before you plant susceptible crops.
  
  

Other Control Methods

• A three-year crop rotation can control anthracnose, black scurf, early blight and verticillium wilt funguses; four- to five-year rotations for controlling phytophtora blight. Planting disease-free seeds, not using overhead irrigation and providing your plants with optimum growing conditions can all work to help control fungus.