Canker on stem. (Photo provided by Tim Tidwell, CDFA, Plant Pathology Laboratory, Plant Pests Diagnostics Center, Sacramento, CA)
Description of Disease:
Canes turn brown from other then winter dieback, stunts plants, occurs in spring
This fungus is most active during the cold time of the year because roses are not actively growing. Becareful of Pruning cuts or wounds on stems because they provide sites of entry for germinating spores. During the dormant months, fungi colonize the tissues, sporulate and are spread to other pruning or wound sites. The disease can really spread under the ideal conditions.
A fungus found in air and soil, caused by dead soil, eco- system, chlorinated
city water, using high nitrogen fertilizers (urea based), poor health of plants due to
improper nutrition, over head watering encourages fungi to spread, planting wrong variety
/wrong location. Improper pruning.
Removal of affected parts, sterilize tools between use, reduce over
head watering, provide soaker or drip, apply compost and mulch. Spray the wounded areas or new cuts with an anti bacterial soultion such as garlic, compost tea or rock dust tea.
When pruning before always make an angular cut close to an active bud site so the callus can form a protective layer before winter. Since winter is when you hvae to be more proactive. Other times of the year, it is enough to use the natural bacterial sprays I talk about. A dormant spray could be used to protect pruning cuts and wounds during the cold and wet winter. You can use a fine horticultural oil for this. In spring, removal of infected canes and a general natural bacterial spray program for fungal diseases should reduce canker problems and protect the plants until they can become vigorous growers once again.
Use a Garden Filter when watering to reduce chlorine in soil.
Bacterial sprays such as Nitron A-35, Shure Crop, Superseaweed,
Agri- Gro etc. see Making Your Own Enzyme
/ Bacterial Spray
Spray a fungus spray such as garlic, add 5
drops garlic oil to 1 gallon water, add 2 drops Dr. Bronners Peppermint
soap (as wetting agent),
Baking soda formula
tablespoons baking soda. Compost tea spray will also encourage
See compost tea page. Compost
Short Term Solutions:
Composting/mulching several times per year, controlling water thru soaker or
drip systems, using a garden filter when ever possible,
Use no chemicals, no high nitrogen fertilizers, use composted animal manures,
feed with an organic fertilizer, use natural sprays mentioned in this book. Natural Spraying Dept
Long Term Solutions:
Proper composting and mulching is important, use soakers or drips system used
best with inline feeder systems, use beneficials (like beneficial nematodes), use only
organic fertilizers (or make your own), use natural foliar, encourage earthworms,
March 10, 2013
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