10 Signs Your Plants Have Fungus (What?!)

Say “fungus” when talking about gardening and many people will give you a puzzled look. However, use other, often more familiar terms, and eyes light up. Fungi include the following array of botanical bad boys.

  • Black spot: common on roses

  • Blight: Fire blight, early blight and late blight

  • Cankers and Galls: Cytospora and crown gall

  • Damping off: as when seedlings suddenly develop weak stems and fall over

  • Mildew: Powdery mildew, gray mildew and downy mildew

  • Mold: Gray mold (botrytis) and yellow slime mold

  • Rust: Raspberry rust, rose rust, asparagus rust and blister rust

  • Smut: Corn smut

  • Lawn diseases: Dollar-spot, brown patch and take-all

  • Scabs: Fruit scab

  • Wilt: Fusarium wilt and Verticillium wilt; tomato plants are a favorite target


Ah, yes, you do recognize some of these names, right?


Fungi are primitive organisms that can’t make their own food; they don’t have the ability to photosynthesize like green plants do. Instead, they must get their food from other organisms. Some types of fungi, like mushrooms, get nutrients from dead, decomposing materials. Other fungi prey on the living. These garden gangsters attack roots, stems, leaves, flowers and fruits.


What Should I Look For?

Most gardeners have seen the results of fungal infestations. Still, it’s often difficult to tell exactly what’s causing the damage because symptoms can vary widely.  Here are a few common signs.


Your Plants May Have Fungus If:

  • Plant is infested with insects; fungus and bugs often work in tandem

  • Leaves are yellow or wilting

  • Foliage has white or gray powdery matter on it

  • Leaves and stems have yellow or orange spots on them

  • Leaves, stems, flowers and/or fruit have soft, watery or rotting spots on them

  • Stems, fruit and/or vegetables have lesions on them

  • Leaves have black spots, sometimes surrounded by yellow

  • Plant growth is stunted

  • Roots and stems have rotted

  • Leaves are deformed


Fungal infestations typically move quickly. For this reason, it is wise to keep a supply of safe, effective fungicides on hand to deploy at the first sight of an outbreak.

If fungal problems are cropping up in your garden, here are our top picks to halt the problems now: Revitalize Biofungicide and Copper Fungicide.

gymnosparangium fuscum leaf diease rust