Is it a fungal problem? Learn to identify common fungal diseases in plants and discover effective organic and conventional treatment methods.
Cylindrocladium root rot is a soilborne fungal disease that rots the roots and crown of ornamentals, then wilts the plant from below. The fungus attacks more than 300 plant species, and its resting bodies can wait in soil for 15…
Northern corn leaf blight hits backyard sweet corn as long cigar-shaped lesions that start on lower leaves and climb. The fungus behind it is Exserohilum turcicum, and wet leaves plus moderate temperatures drive every new infection. 9 strategies below protect…
Verticillium wilt has no cure once it enters the xylem. The fungus plugs the water pipes from inside, so a maple wilts in moist soil and no spray reaches the blockage. 10 strategies below protect the plants around the sick…
Walk the lawn at sunrise and look for straw-colored circles the size of a silver dollar before the dew dries. That is dollar spot, a leaf fungus that shows up on hungry lawns in wet weather. The rest of this…
Stemphylium gray leaf spot on tomato strips leaves while leaving fruit untouched. The fungus spots lower leaves first, then dries whole leaflets gray and crispy until they drop. 9 strategies below tell it apart from early blight and save the…
White rot on onion and garlic has no cure once it reaches the bulb. The fungus waits in the soil as tiny black sclerotia, and a single sclerotium per 20 pounds of soil can start disease in a bed. The…
Brown rot has no cure once it infects a fruit. A peach that looks sound at breakfast can carry a brown spot by dinner, and a ripe cherry can rot clean through within 2 days of infection. The 10 strategies…
Those red dots on your photinia leaves are almost certainly Entomosporium leaf spot, and the honest news is that most cases look worse than they are. Light infections are cosmetic. Severe ones defoliate shrubs and demand a real plan. This…
7 moves separate Macrophoma leaf spot on boxwood from the two diseases that actually kill boxwood. Macrophoma leaf spot on boxwood turns older leaves straw-colored and dots them with tiny black fruiting bodies. The shrub looks doomed. The fungus behind…
Pecan scab turns a backyard pecan crop black before it ever fills. The fungus spots leaves, twigs, and shucks, drops nuts early, and can wipe out a whole season on a susceptible tree. 10 strategies below protect the crop, starting…
Web blight is a fast foliar disease caused by the fungus Rhizoctonia solani. It webs leaves together with fine tan mycelium, turns them dark brown or black, and collapses whole plants in hot humid weather. The 9 strategies below stop…
Septoria leaf spot strips tomato leaves from the bottom up, and it rarely touches the fruit. The 10 strategies below hold the canopy by cutting splash, drying leaves fast, and spraying only when rain will not stop. Start at the…
Those tan spots with dark rings on your beet leaves have a name: Phoma leaf spot, caused by the seed-borne fungus Phoma betae. The spots run 1 to 2 centimeters across, and the same fungus rots seedlings at the soil…
White mold kills from the stem outward. The fungus Sclerotinia sclerotiorum rots stems, girdles them, and leaves cottony white growth studded with hard black sclerotia. The 10 strategies below separate this disease from two harmless look-alikes and keep it from…
Pseudocercospora leaf spot turns lilac leaves brown and drops them early, and 8 cleanup-first strategies hold the line. The spots look alarming by late summer. The shrub usually survives them. The disease hits two ornamental shrubs here: lilac and mountain…
Fusarium wilt has no cure once it reaches the xylem. The fungus blocks the water pipes from inside, so a tomato wilts in moist soil and no spray reaches the blockage. 11 no-spray strategies below save the crop around the…
Your tomato plant looked fine yesterday. Today it is wilted flat, and when you part the mulch at its base you find a fan of white threads crawling across the stem, studded with tiny tan balls the size of mustard…
That ghostly white dust on your rose leaves is powdery mildew, and it looks worse than it usually is. The fungus behind it, Podosphaera pannosa, feeds on the leaf surface without invading the tissue underneath, and it spreads fastest on…
Purple-stained soybean seeds are the work of a single fungus, Cercospora kikuchii, and in most harvests the purple color costs the grower more in grain dockage than in actual yield. Leaf damage from the same fungus usually trims less than…
Yes, you can treat Phomopsis canker at home. Cut out every cankered branch 6 to 12 inches below the visible damage, disinfect your tools between cuts, and destroy the debris. Do the work in dry weather. That prune-out-and-dispose protocol is…
