How to Identify Rose Diseases
My mother-in-law's favorite flower is the rose. She lives in the desert and diligently tends to her rose bushes, with moderate results. We came across some roses on the other side of this same desert town, which have been virtually neglected, yet they amazingly thrive. Yet, even the most lucky of neglectant rose gardeners can encounter disease which can bring down a seemingly hardy rose garden. Correctly identifying the disease will assist in its cure.
- Difficulty:
- Moderate
Instructions
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1
Notice if the leaves have white spots with dark red borders. The spots will turn yellow and the leaves will become riddled with holes. This is spot anthracnose. The rose stems will also show signs of this ailment, by way of brown spots with light centers. This is a fungus that develops in the winter and produces spores that spread. Prune off the infected stems come spring. Chemical control include an application of lime-sulfur when the plant is still dormant, followed by weekly treatments during the growing season with either ferbam, folpet, captan or zineb.
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2
Look for rust. Rust is a reddish orange warty looking growth that appears on the underside of the leaf. The spores can survive the winter and return in the spring. Infected areas should be removed and burned. Spray in the early spring (including the underside of the leaf) with either ferbam, zineb, or sulfur.
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3
Check the leaves for a powder coating. This is powdery mildew, which can cause leaves to curl and dry up, and buds to shrivel. This is a common rose disease, which is caused by a fungus. Roses with too little sun, planted closely together or bushes in humid climates are especially susceptible to powdery mildew. To help avoid the problem, water early in the day, allowing the plant to dry.
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4
Look at the leaves again. Are there black spots? This is rose blackspot, which is spread by spores that can be carried from plant to plant by the elements. This is another disease that can benefit from early morning watering, and distance between the bushes. The infected leaves and stems should be removed.
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5
Inspect for tumor like growths, usually found close to the soil. A plant that has been injured from gardening tools is susceptible to this ailment, which is called crown gall. The infected areas should be removed and burned. Sanitize clippers with a solution of 70 percent alcohol. Chemical control includes spaying with streptomycin during the growing season, every two weeks.
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6
Look for dark woody sections, primarily on the cane portion of the bush. This is called canker, and is caused by fungi. One way for the plant to be infected is by using a rose clipper that hasn't been sanitized. Improper pruning can contribute to canker infection. Prune off the infected stems, and sanitize clippers with a solution of 70 percent alcohol. Canker can be controlled by spraying with lime-sulfer prior to the beginning of spring growth, and then weekly spraying of either ferbam, folpet, captan or zineb.
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Tips & Warnings
Always use clippers that have first been sanitized.
