canker in plum trees

[wurzelgummidge]

ive got three plum trees that have canker courtesy of a next door neighbour
and am battling to save them which so far am winning,most people say I'm mad but I feel a kind of spiritual connection with trees,and hate them being cut down if at all possible to save them, a bloke in the local garden centre said you can get rid of the disease by using a copper based fungicide which is injected directly into the tree over three or four years,this year there are loads of plums on each tree.they are self pollinating victorias.
would like to post picys but no idea how as cant work out how to use digi cam
I do have a high definition web cam one day might learn how to use it.
the canker takes the form of sap leakage that forms into brown resin.
faliure is not an option in my book

[Jess]

Hi wurzel

I think you are after Bordeaux mixture. This is copper sulphate mixed with slaked lime. Instructions need to be followed very carefully or you will end up doing more harm than good.
https://www.organiccatalog.com/catalog/product_info.php?cPath=61_181&products_id=517
Before using it make sure diseased patches are cut out back to good wood. Completely remove infected branches girdled and killed by cankers. Burn the infected wood. Treat tools after each cut with 1 part bleach to 4 parts water.
You will also need to instigate the following to reduce any further infection....
Delay dormant pruning until January or February. Summer pruning should be done after harvest, when weather is dry.
Remove weeds and grass from around the base of trees to increase air circulation and keep the trunk dry.
In summer, small cankers may be cut out using the following method.
Cut away bark above and around the edges of the infected area. Use sharp tools, and leave wound margins smooth and neat. Do not use a sprinkler to water or splashback may reinfect open cuts .
Treat with a wound dressing before autumn rains begin.

Found this...quote [Cauterizing cankers using a hand-held propane burner has been used with some success in New Zealand]...Might be worth a try as a last resort.

Good luck. Hope you can save them.

[wurzelgummidge]

hi jess
thanks for the info will add that to what I'm doing I have been cutting out bits and burning them and treating with canker killer I got from local garden centre. propane gas torch sounds interesting for cauterising wounds.
one thing that is confusing is pruning as some say you can prune small amounts after flowering right through to leaf drop in autumn,and others say only after harvest.

[Jess]

hi jess
one thing that is confusing is pruning as some say you can prune small amounts after flowering right through to leaf drop in autumn,and others say only after harvest.

You need to prune after harvest to avoid the canker causing fungus. The fungus is more active in cooler, wetter weather so by pruning in summer you will avoid it as much as is possible.
By delaying dormant pruning until Jan/Feb you are pruning just before the tree kicks into spring growth. This is when it is at its most vigorous, with sap rising, which will again give it a chance to beat the canker.