Mr. Stakman:  Plum pocket is caused by a fungus which is supposed to infect mostly when the flower buds are just beginning to swell, especially in cold, wet weather.  Plum pocket causes the fruit to overgrow and destroys the pit, and big bladder or sack-like fruits are produced instead of the normal fruit.  The fungus that causes it gets into the twig and is supposed to live there year after year.  Therefore pathologists usually recommend cutting out and burning affected branches and even trees that bear pocketed plums several seasons in succession.  Our experiments with plum pocket have not extended far enough to enable me to say anything definite about it.

Mr. Hall:  With us in western Minnesota this year this plum pocket got all the plums that the frost didn’t get.  If we were to cut off the twigs we would have to chop off the trees.

Mr. Stakman:  When a tree becomes so badly infected that practically all of the branches produce pocketed plums year after year you can’t expect very much normal fruit.  Sometimes you might get some, but usually not very many.

Mr. Graves (Wisconsin):  Do you use your black leaf 40 in conjunction with your Bordeaux or lime-sulphur?

Mr. Ruggles:  Yes, you can.

Mr. Graves:  Doesn’t it counteract the result?

Mr. Ruggles:  No, it does not.

Mr. Stakman:  I used this year lime-sulphur and black leaf 40 together.

Mr. Graves:  You say you got the same results from black leaf 40 in that mixture?

Mr. Stakman:  It killed the plant lice; that is all I wanted.

Mr. Graves:  We had some experiences that indicated that black leaf counteracted the other results.

Mr. Stakman:  Yes, sir, I think that has been the impression, but I think there have been some experiments more recently to show that the black leaf 40 can be used in conjunction with other sprays without counteracting their results.

Mr. Richardson:  Did you ever know the plum pocket to come unless we had cold weather about the time of blossoming and lots of east wind?

Mr. Stakman:  Yes, a little; I have seen it mostly when there was cold weather, however, and as I said before it usually isn’t so serious unless there is cold, wet weather.

Mr. Richardson:  I settled out in Martin County, Minnesota, in 1866, and in all my experience I never saw plum pocket unless we had the right kind of cold weather at the time of the blossoming.  I had my plums all killed and destroyed one year and never did anything for it, and when we had the right kind of weather I never had any trouble.

Mr. Stakman:  When you have cold, wet weather, as I mentioned before, infection takes place much more rapidly than it does at other times.  There is some evidence to show that the fungus lives in the twigs and that affected ones should be cut out.

Mr. Richardson:  Yes, but these didn’t bear any for four or five years, and when we got the right kind of weather I got good plums.