The following question arrived the other day....
Please could you tell me how I can get rid of the woolly aphis which is covering a Worcester - Pearmain apple tree in my garden ?It has been getting steadily worse over the last three years and appears to produce large knobbly growths on the branches and bark. The tree is in a sunny, sheltered position.
..................Woolly aphis - once you've got it on a tree, you're stuck with it. There is no magic spray or treatment. Some varieties are susceptible - I have one which has it (Ribston Pippin). "Sunny and sheltered" makes it worse - aphids - including woolly aphis - love it.
But this is how you control it..... assuming you can reach all the branches. If it's a full size tree there isn't much you can do, except to clean the trunk and lower branches, and the tree may deteriorate further.
Get a hand-sprayer, fill it with some sort of bug killer - the sort you buy as a concentrate and dilute with water . Also, get a sharp knife with a blade which will lock into position.
Slice off the knobbly growths. This may mean taking off small twigs and spurs; they won't fruit again anyway, and they will re-infect the following year. Slice off any small "bobbles" on the bark. These (and the other swellings you mention) are canker, and this is the real danger to the tree. You'll see the familiar red colouration inside. Summer prune - take off all excess growth and unwanted leaves. When you've done this, put on some old washing up gloves, get a toothbrush, and spray and scrub all the sources of white "wool" on the tree*. You gloves will become a sticky mess. Be thorough.
Lastly, do some poking and prodding with your knife, and remove all bits of old, dead bark. Woolly aphis hides here. Give these bits a scrub and spray, too. Don't worry about cutting off bark. Remove all the canker. As long as you don't "ring" a branch, the bark will flow over the wound over the coming months.
Leave it a week, and do it again. It'll be quicker and the reinfection will be small.
Then do it again as necessary through out the growing season.
Woolly aphis will not be eradicated by this treatment, but it will be controlled and should no longer be a problem.
(*you can alternatively use petrol or meths, and dip your toothbrush into it before you scrub).
After some correspondence, Brian Western told
me about a method he has devised:
I seem to have found a simple cure. I don't
think it's a commercial possibility but I
remember that you too are troubled by this problem, so
you might care to try my "recipe" out. Here it is:-
Dilute a quantity, ( 1pt.? ), of a reputable aphid control liquid,
following the recommendations on the container; now comes the clever
bit: add another pint of diluted Jeyes Fluid (diluted with three times
the amount of water that you would normally use for a Winter wash).
I tried it with double the water but this burns the trees foliage
and the plants underneath the tree and even now I rinse the aphis
control spray from any other plants, simply by using a watering can
of plain water. I treated my apple tree about three weeks ago and
previously infested areas are still free of woolly and other aphids.
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