He says very truly, that looking at the winter quarters of the mite pests being most especially in the buds, such measures as:—
(1) Breaking off and destroying the infested buds.[[65]] (2) Cutting off the infested shoots just above the ground, and so getting new shoots. (3) Only using uninfested pieces for propagation—could not, he thinks, fail to be of service, if carried out carefully. I quite agree with Dr. Nalepa so far as that, without these measures, infestation would be worse than it is. In a small amount of growth (such as bushes in a private garden), I can speak from my own personal experience of having sometimes satisfactorily checked the spread of these or similar causes of injury by employing dressings. But it is a very different matter where blackcurrant bushes are grown by acres together; and I greatly doubt whether, even if consideration of cost were put aside, it would be within possibility to get this wood (or grove) of bushes, so examined and so expurgated of evil, as not to leave centres for spread.)
It always strikes me as a very curious circumstance that (so far as I am aware) the black currant is not affected by this Phytoptus on the Continent, or at least in the large part of it in which the attacks are noted by Kaltenbach or Taschenberg. Do you think it can be that the black currant is there of a somewhat different kind which repels Phytoptus attack, just as some kinds of American vines are not as subject as others to Phylloxera? It occurs to me that it may be well worth while to import some hundreds of plants and plant them, of course on what is considered clean ground, and see what comes of it. I should like your views after you have well thought the matter over. I cannot expect the expense of an experiment of mine to be borne by any Company, but I should much like it trustworthily tried, and if you could give me some guidance as to where to apply on the Continent, and cost (a rough estimate), I might be able to get the plants, and with your permission send a good consignment to yourself.
April 27, 1897.
I have to-day heard from Dr. Ritzema Bos about the Phytoptus ribis, and he tells me that in Holland he knows many localities where this infestation is a scourge to fruit-growers, but it is always the black currant which is attacked. They do not have it there in the red currant, Ribes rubrum. He says that he is not acquainted with any better remedies than those mentioned in my letter, but that he considers it an excellent idea to seek for varieties or families of black-currants, Ribes nigrum, which may be “Phytoptus proof.” He does not himself know positively whether there are districts in Holland not attacked by the Phytoptus, and whether in attacked districts there may be varieties that do not suffer. Therefore he is going to ask for information on this head from horticulturists and fruit-growers, and will write me again. I think it is very kind of him to take so much trouble to help us, and from his position I expect he will easily obtain whatever information is to be had, and I will be sure to let you know. It is very curious about the red currant being attacked in some parts of the Continent and not in others.
November 30, 1897.
I have this afternoon heard from Professor J. Jablonowski, Assistant at the State Entomological Station, Budapest, that he “sends now the promised black-currants.” I expect these will be supposed “mite-proof” plants, as he says that he hopes they will be serviceable for the proposed experiment—but he does not explain; only that they have been given to him by his friend, the Director of the Horticultural Institute, Desiderius Angyal (I do not know what prefix I should write). When the plants arrive I propose to divide them (if you please) between yourself and Mr. John Speir—it would be exceedingly interesting if there really should turn out to be a mite-proof black currant. But meanwhile Professor Jablonowski would very much like to have a specimen of the mite galls, for he has never seen them. If it would not be too much trouble, I should be very greatly obliged if you would be kind enough to let me have two or three bits of twigs with galls, if any are showing enough now to be noticeable, and I would send them on.
December 4, 1897.
Many thanks for the supply of galls, which I shall duly send to the Professor, and I earnestly hope that he will not infest Hungary with them! The consignment came to hand from him yesterday evening, but it is in the form of shoots as cuttings, so I now send you about half in a registered letter. If the pieces root properly I should think it would be best to plant them amongst the infested currants—as they are so few it would not be much trouble—and there is just a chance that they may be mite-proof. I do not myself (much as I regret it) think that there is any safety in washes and that sort of treatment, but as I write the idea comes into my mind whether, as with us, the Ribes rubrum (red currant) seems mite-proof—anything could be done by grafting black on red. Would they graft? or is my idea quite chimerical? The black currant shoots are var. “bang-up,” which suggests England as their original country.
I do not know whether you have to do with importing apple fruit, but I see from Dr. Fletcher’s (Canadian) Entomological Report that there is a newly observed fruit maggot in, I think (without special reference), the District of Columbia.