Watch for Alternanthera Mosaic Virus This Spring

Posted by Brian Sparks|May 17, 2022

Alternanthera mosaic virus; Photo: Margery Daughtrey, Cornell University

Alternanthera mosaic virus (AltMV) infects a broad host range, with hosts from at least 30 taxonomic families including many commonly grown greenhouse and herbaceous ornamentals. This season, AltMV has been diagnosed on portulaca with symptoms of distorted leaves and chlorotic flecking and spots.

In a recent e-Gro alert, Nora Catlin from Cornell University outlines how AltMV often causes a chlorotic spotting or flecking, mosaic, or mottle (light-colored or yellowed irregular patterns or patches on the leaf), or leaf distortion, but can also cause necrotic spots and lesions. Symptoms observed and symptom severity can vary depending on the host plant and the virus strain present. Often symptoms are subtle difficult to discern. Growers should enlist the assistance of a diagnostic lab or a virus test kit.

This virus can be spread mechanically, meaning that it can spread from infected to healthy plants via handling by workers and tools. The virus is not known to be spread by insects or mites.

Management practices for AltMV include maintaining good sanitation practices to avoid spreading the disease: discarding infected plants, keeping areas weed free, avoiding handling healthy plants after infected plants, and disinfesting tools and any materials that may have been contaminated with viral particles with an appropriate product.