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Crown Gall



P_crowngall

Crown Gall

Usually appear in

All Seasons


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Caused By:-     The Bacterium Agrobacterium tumefaciens

Description

Crown gall is a disease of roots and stems and occurs on a large number of plants from cherries to roses. The name is derived from the rough galls that develop at the crown of the plant i.e. the point at the soil line where the main roots join the stem. It may also occur on the roots or branches of the plant. Galls vary considerably in size from to large, with the majority being small. Young galls are soft on the surface and have a light, tan-coloured, frosty appearance. As the galls become older, they grow darker, turning almost black, and usually are hard and woody. The effects on the plant is usually not noticeable until it gets severely infected when the plant becomes stunted and sick. Crown Gall often allows other pathogens to gain entry especially in herbaceous plants. Grafting is often a cause of the entry of the Crown Gall mechanical damage by animals and insects is another entry point of this disease.
See also these other Galls ACER GALL MITES, ACORN GALL MITES, AZELAE GALL, BEECH GALL MIDGE, BLACKCURRANT GALL MIDGE, BROOM GALL MIDGE, CAMELLIA GALL, EUONOMUS GALL, FELT GALL MITES, GALLS, GALL WASP, GLEDITSIA POD GALL MIDGE, HEMEROCALLIS GALL MIDGE, HAWTHORN BUTTON TOP GALL MIDGE, KNOPPER GALL OF ACORNS, LEAFY GALL, LIME NAIL GALL MITE, OAK GALL WASP, PEAR LEAF BLISTER MITE, PINAPPLE GALL ALDELGID, PLUM GALL MIDGE, ROBINS PINCUSHION, TURNIP GALL WEEVIL, VINE ERINOSE GALL MITE, VIOLET GALL MIDGE, WILLOW BEAN GALL SAWFLY.


Control

There are over 600 species of plants which are susceptible to crown gall.
Plants should becarefully examined before introducing them to your garden.
You should avoid those with suspicious swellings on the roots or stems.
In the case of crown gall it is worth the extra checks to prevent Crown Gall than the cost of curing it.
The infected plants is to be destroyed and plants that are not susceptible to the gall grown, like like Boxwood (Buxus spp.) and holly (Ilex spp.), should be planted in that area for up to three years. This should get rid of the infection.
Fumigating the soil with chloropicrin or methyl bromide is possible.
Good hygiene when pruning such as dipping the pruners in a weak solution of bleach will prevent spreading the disease.
Biological control is possible for a number of fruit and ornamental crops. This involves inoculating newly grafted or recently lifted transplants or cuttings with a bacterium (Agrobacterium radiobactor) that is closely related to the one causing crown gall.
This prevents the crown gall bacterium from infecting wounds on the plant.

P_crowngall P_crowngall2

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