HaltingHollyhockRust:Rust disease seems to disfigure my hollyhocks almost every year. Is there anything I can do to put a stopto it.

摘要

Staples of the cottage garden, hollyhocks have much to recommend them. They produce spires of cheery, saucer-shaped, single or double flowers on tall, leafy stems that hold the flowers up where they're easily enjoyed. Unfortunately, they also have hollyhock rust (Puccinia malvacearum), a fungal infection that speckles the rounded leaves and sturdy stems with rusty red spots and gradually causes plants to lose their leaves from the ground upward, leaving them bare-legged and bedraggled.Infection is usually first noticed as small yellowish spots on leaves' upper surfaces. Check the undersides of the foliage to see the coral to red-orange pustules where spores will form to continue the spread of the disease. Each pustule can produce about 5,000 spores, says Janna Beckerman, associate professor of plant pathology and extension specialist at Purdue University. This makes it difficult to stop hollyhock rust from having its way with susceptible plants in humid or wet weather conditions thatfavor fungal diseases. Take steps to rein in rust as soon as pustules appear: Remove infected leaves, clean up dead leaves, thin plants to improve air movement, and avoid working amid wet plants or wetting the foliage when watering. You have only to miss an infected leaf or two to leave more than enough spores in the garden for the disease to continue its march over your hollyhocks, Beckerman warns.