I have been trying to grow some plums, including Victoria in Italy, where I live. Over the last three years, as the trees got established, I have not had a single plum to eat, though the trees have set many. Finally the problem was identified as the Plum Fruit Moth. I was advised the problem was not soluble for the private gardener; If you look at the measures recommended by a number of fruit-growing States in the USA you will understand why. They have the problem,shared with Italy, that there may be several generations of the moth in a single summer.
My neighbour tells me he cut down all his plum tree years ago, because he never got any fruit from them
So I decided to try my luck with netting two of the trees a Victoria and a Reine Claude Yellow.
It was difficult to get info re the size of the moth so I tried two different nets.
On the Reine Claude I used fleece over a number of twigs and branches bearing fruit, leaving other fruit unprotected.
On the Victoria I covered the whole tree, about 2 1/2 m tall, with a net made of green debris netting. For this tree I also covered the ground within the net with layers of black plastic tied tightly round the trunk, as all previously fallen fruit had been left where they lay..
Both trials were a success. In the case of the Reine Claude the netted fruit matured without any infection. None of the un-netted fruit matured, all falling off before maturity.
In the case of the Victoria the tree suffered from drought in July, losing many of its leaves, and when I began to water it many of the fruit split and then dropped off. However none of the fallen fruit showed signs of infection. This month (September) the remaining fruit on the Victoria has been ripening satisfactorily, with none of the picked fruit showing any signs of infection. The fruit is drier in texture than I would expect from a Victoria plum in England, so I will have to see if that can be cured by watering, or if it is just a result of the summer heat.
I have posted pics of the two trees netted:- DSC02021s.JPG