Lawn and Garden Care: Plant Disease Management

Katy Deitz, Alassane Sow, Claudia A. Paez, Jeffrey Eickwort, Michelle A. Jusino, andMatthew E. Smith

Starting in 2019 in northern and central Florida, a thread blight caused by a previously undescribed fungus was observed with increasing frequency, affecting both hardwood and conifer hosts with a higher prevalence in wet, shaded environments. This emerging disease, called relampago blight, is caused by the fungus Parvodontia relampaga and is characterized by its distinct white, lightning-shaped rhizomorphs (fungal cords) that grow on the stems and branches of affected host plants. When the fungus fully develops, it can also grow on the undersides of plant leaves, causing dieback of leaves and small branches. This fungus has been found on a wide array of host plants and detected in 31 counties throughout Florida.

C. Benton Willis, Michael Goodnight, Jessica Velte, Marin T. Brewer, andMatthew E. Smith

Exobasidium fungi are plant pathogens that primarily infect plants in the Ericaceae family, including blueberries and azaleas. Their infections cause plant cells to proliferate (hyperplasia) and expand (hypertrophy). The fungi then use the increased surface area to produce spores. These changes manifest as symptoms on the host plant, varying by species of Exobasidium. The range of symptoms includes leaf and fruit spots, blisters, shoot proliferation (witches' broom), and galls. Infected plant tissues can also become swollen and distorted, as well as chlorotic (yellow) or discolored (reddish to pink). As this infected tissue matures, the surface becomes white and powdery from fungal spore production. Exobasidium fungi tend to cause symptoms on the plant during ideal weather conditions but can likely survive on the leaf surface or other available substrates year-round. Disease management includes chemical applications and cultural practices before the spores have the chance to mature.

Philip F. Harmon andAaron J. Palmateer

[ABSTRACT]

Stephen H. Brown, Philip F. Harmon, Sheryl van der Heiden, Ryan Czaplewski, Ralph E. Mitchell, andDavid Outerbridge

Fungi make up approximately 90% of known plant pathogens. One of the most common fungal diseases of plants is anthracnose. The name anthracnose represents a group of related fungal diseases that affect many different landscape and crop plants. This publication is intended to provide information to professional landscapers, pest control operators, Extension agents, and homeowners on how to recognize and potentially manage anthracnose diseases of landscape plants. It includes 47 images of common plants affected by the disease.

Philip F. Harmon, Carrie L. Harmon, Aaron J. Palmateer, andStephen H. Brown

A UF/IFAS numbered Fact Sheet.

N. Peres, P. F. Harmon, and C. L. Harmon

A UF/IFAS numbered Fact Sheet.