Plum Tree's Last Chance!

[Guest]

I have a Victoria plum tree that is cropping well but I have been unable to eat anything as the fruit has been rendered useless by pinky coloured maggots last year was the final straw! I winter washed the tree, applied greasebands & hung FOUR of those moth traps in it, yet I still lost 90% of the crop so this year I intend to resort to a chemical spray, but so far I have not been able to find any info on what you can use to spray it & also when to spray it, can anyone help please?

[Helen]

Anyone?

[valmarg]

Surely not every plum is infected. We have the same problem, but we sort the wheat from the chaff, and when the plums are split open, those with the maggots inside are thrown away (and the maggots are killed, thereby removing the next generation), those without are used.

It is all part of the rich organic patchwork!

Believe me, I would prefer to eat my somewhat dodgy homegrown victoria plums, than something that has been flown halfway round the planet, and is of very (to me) dubious organic veracity.

I welcome the organic movement, but I find the further the food has travelled, the less I accept the organic authenicity.

Sorry, but when it comes to organic, I do not trust anything produced outside the UK.

Am I "a voice crying in the wilderness?"

[Helen]

Pretty much every one of them had a maggot
we had about 8 left to eat! I think our problem stems from a couple of overgrown Damson trees in next doors garden they look pretty manky!

Please don't get me wrong I don't go spraying chemicals around willy nilly but I do (spray) when it comes to eating a crop or not! its just I can't seem to find anything to spray them with!

[Jenny Green]

According to Hessayon you should spray with Fenitrothion 7 - 10 days after petal fall. Not sure if this is still available though.

[Helen]

No its not, one of the many that got banned!

[Jenny Green]

A very, very big tent of fleece and hand pollination?

[nog]

I feed the tree with Blood Fish Bone about now and then water it. I find that if you let the fruit ripen totally on the tree you have problems. Otherwisee you are ok. I use most of Plums and Damsons for Jam and pies and tarts. So I cut out the nasty bits and use the rest. I get about 1 in 50 with a problem. Spose it just luck. But mine are the only Plum and Damson trees about.

[vivie veg]

May I ask what you and your neighbour (with the doggy damsons) are doing with your moggot infessed fruit?

If you leave them to rot on the ground or even in a compost bin, I would imagine that the grubs would continue feeding and develope into adults ready to lay their eggs on your newly pollenated trees next year!!!!!! SO each year the problem would get worst.

So clear up your maggotty fruit,

I must admit that I would be like Nog and just cut the fruit open, cut out affected bits and make the rest into jam. However I am not squeemish having been bought up by my mother who would cook the damsons whole and we would have to fish out the stones/grubs while eating them!

You may find that a ready cold winter will help to reduce the number of adults which survive.

[Guest]

I would have recommended using fenitrothion. It is the most effective bug killer available. I can't see any indication that it has been withdrawn:

http://www.pesticides.gov.uk/approvals.asp?id=996

[Martin D.]

Some people in the RHS Fruit Group believe that the Plum Moth Pheremone traps work well - I've tried them and don't have such a high percentage of maggoty fruit as some of you seem to suffer. It's usually up to 20% which are affected (I cut every fruit open to check before using them!) and they tend to be the ones which ripen and drop from the tree first (the same as with maggoty apples). There's some thought that it's best to put the plum traps in your apple trees and vice-versa (or any other tree I guess), rather than attracting the male plum moths to your plum tree thinking that there's a female moth waiting there, if you see what I mean.
Professional growers tend to use them to monitor moth levels to tell them when the moth population is large enough to mean that spraying is needed, but I haven't been that orgainsed yet with my small orchard. So, I feel that the traps are worth a try
Best wishes Martin

[Vivien Z]

We have just given our old plum tree a winter tar oil wash. We inherited the tree when we moved to this house about 6 years ago, and it has always suffered from maggoty fruit. The tar oil wash did work really well, but we didn't manage to get around to it last year. I never found the pheremone traps to be very effective. And all this for.....the sourest plums in England! They look lovely, but they are like concentrated fruit acid and only really any good for chutney! Still, the birds like the tree and it looks really pretty in flower.

[Martin D.]

I've given Winter Tar Oil Wash a go, too, but cannot say whether any improvements seen in Plum Moth control were down to the pheremone traps or the oil wash. The Tar Oil Wash was withdrawn from the list of approved products as of the end of 2004 (both professional and amateur use, more's the pity) - chemical controls listed in the last edition of the Fruit Garden Displayed are fenitrothion, pirimiphos-methyl or permethrin. I don't think of these are approved for amateur use now - you'll only usually find just Derris and Bifenthrin in most garden centres. The RHS state that there are no chemical controls for Plum Moth (they must be referring to amateur use) so presumably Derris and Bifenthrin don't work very well...
Growing Success do an approved Winter Wash based on fatty acids/oils which is meant to work OK so could be worth trying. If your tree is the only local source of infestation a deep mulch applied in Spring under the tree might help stop the moths emerging.
Good luck!
Martin

[Helen]

I've now had a chat with a local fruit grower who has advised me to lightly cultivate the soil beneath the tree so that this desturbs the pupae, you do this around feb/mar time & again in april just going over the soil with a hoe moving the top 2" or so, hopefully the birds will be attracted to them or as I have bantams in the garden I could throw a few pellets around the bottom of the tree to encourage them to scratch around under the tree, then you wait for blossom time & once approx half of the petals have fallen spray with Derris, then again 7 days later, this should kill eggs/larvae before they have chance to enter the fruit, I can see this working for someone who has a single tree in a garden but as I have the neighbours problem damson tree I think I'm up against it with that but I'll give it a go & may be report back later this year! I have already given it a winter wash & I'll do it again at the end of the month, I will also put the pheremone traps in the apple tree next to it

Helen

[jct]

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 a couple of photos showing the netting in place.

DSC02021s.JPG
http://www38.zippyshare.com/v/71048748/file.html

DSC02024s.JPG
http://www39.zippyshare.com/v/79139555/file.html

I hope this will be helpful to other sufferers form the Plum Fruit Moth!


jct