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DISEASES OF ORCHARD FRUITS.

In the absence of even a moderate fruit crop, orchards as well as their diseases have received diminished attention. Freezing injury to trees has already been treated at sufficient length.

Like all cold spring periods, 1907 witnessed an excessive amount of peach leaf curl, Exoascus deformans, and for like reasons there was a phenomenal amount of plum pockets or bladders, Exoascus pruni, upon certain varieties of American plums. Leaf curl of the peach is most successfully controlled by both the sulfur sprays used upon dormant trees for scale insects and by Bordeaux mixture, applied before blossoming in spring. Occasionally, however, a grower lets the curl slip up on him. I am sometimes led to inquire, "How would we grow Elberta and some other present day standard varieties of peaches, were our knowledge of control of leaf curl no further advanced than when these varieties were introduced?" Here, as elsewhere, there has been certain progress.

I would suggest in the same connection that the off fruit year is a good time to clear up sources of the rot infection of stone fruits. Remember, the cluster-cups of this fungus grow from old mummies the second year. This covers both rot of peaches and rot of plums.

Shot-hole or leaf-spot fungus of plum and cherry, Cylindrosporium padi, was quite bad during the rainy late summer. Trees defoliated very early may be too full of sap from after-growth to resist freezing in winter.

On the matter of apple diseases I have little new to offer beyond the freezing injury. We have determined a new apple scurf disease fungus, Phoma prunicola, that was sent from Muskingum county and also collected on my grounds at Wooster, but in both cases it comes as a leaf-spot. Upon the leaves it appears as a rather insignificant leaf-spot, possibly of no great importance as a foliage disease.

Stevens* of North Carolina has worked upon this species as a disease of twigs similar in effects to Sphaeropsis canker. We may not have the same type with us.

I may mention also a good deal of apple rust, Roestelia, during the season upon wild Crataegus as well as cultivated apple leaves. This is the summer stage of the cedar rust, of which the spring cedar apples are the winter form. Such rust is to be expected in the neighborhood of infected cedar trees.

I ought possibly also to call attention to the common dropping of fruit tree leaves, especially in seasons like last, when the interior leaves become shaded by newer and later growth. Occasionally the yellowed leaves of this sort fal very freely; this was noticeably the case shortly after the bright weather in July. Such leaves seem to have done their work and, not being where they are stimulated by the sunlight, perish through lack of work. It is a natural condition and not due to disease, as sometimes feared.

DISEASES OF SMALL FRUITS.

One curious disease of strawberries was studied. This was an external blackening of the berries, accompanied by rotting after turning very black; a "smudge," almost a black-rot of strawberries. The fungus in the rot appeared to be a species of Botrytis and the attacks occur where the berries come in contact with the mulch of manure. It seems probable that the fungus was derived from the manure and that it will scarcely prove serious in normal years. The trouble did quite a little damage and is worth watching, however. Strawberry leaf-spot was very abundant during 1907.

Bull. North Car. Expt. Station 196: 54: 1907.

The situation with raspberries and blackberries under cultivation is quite unsatisfactory, owing especially to crown-gall and to anthracnose. I can report. no new developments in this line.

Currants are steadily dying out by reason of cane-blight, Nectria, etc., and new plantings are limited.

DISEASES OF FOREST AND SHADE TREES AND ORNAMENTAL SHRUBBERY.

The discussion of tree planting and forest care calls renewed attention to diseases within this whole range of forest trees, shade trees and ornamental plantings.

So little has yet been done upon the diseases of Ohio woodlots or forests that little can be offered. We know that wound fungi are very numerous and that localized decay and final death of trees is brought about by these gillfungi or Agarics. Much has been done in Europe in this line, which is strictly that of forest pathology. The mention of the subject will suffice here.

Oak leaves were much curled by reason of greenfly; and oak leaf-spot, attributed to Phoma, was also collected in Jackson county by the Department of Forestry. In plantings of catalpa a good deal of complaint has arisen by reason of the death of terminal shoots and because of dying leaves. The dying shoots are largely caused by insect larvae which bore into the part. These have been reported upon by the entomologist in circular letter, with illustrations, which has been distributed.

The leaf-spot diseases are often quite serious. Of them we may distinguish two diseases, viz: the common leaf-spot, due to Phyllosticta Catalpae, which is rarely serious, and the confluent leaf-spot, caused by a species of Alternaria, which may prove menacing on new plantings. Remedies have not as yet been thoroughly worked out.

Much complaint was made during the summer of 1907 by reason of leaf collapse or tip-burn in maple leaves. This came at such a time as to suggest, in the absence of parasites, a physiological trouble, probably explained by the conditions which were disastrous to oats, alfalfa, etc., in so far as these may. apply to maples. Ornamental plantings were much injured by freezing as before mentioned. Two distinct fungous diseases of privet have, I believe, been previously reported.

GRAIN DISEASES.

Although not strictly a horticultural topic, it has been my custom to touch upon grain diseases.

These have been very prominent in 1907; especially is this true of the smuts and scab in wheat, the ergot in rye and the smuts of corn and oats. Wheat mildew, Erysiphe graminis, was present to an unprecedented extent upon wheat, causing early dying of the blades and conspicuous coating of the culms. This showed as the oidium stage in the fall of 1906 along with or earlier than the fall outbreak of rust, yet I can find little evidence of injury by the mildew, although it certainly did harm. While rust of wheat was most widespread in occurrence, the injury to the crop appeared to be slight and plump grain was the rule. The unprecedented vegetative growth of the wheat plant may in some way be associated with the plump crop, though it could not bring heavy yields.

Wheat scab, Fusarium roseum, was uncommonly plentiful and dead heads or parts of heads with white, shrunken kernels were much in evidence. The

hairy glumes of some wheats seem to catch the spores of disease. Velvet Chaff showed about 5 to 7 per cent. scab at the station, while Lebanon, Deitz, Fulcaster and others showed high percentages and much bad grain, and Poole was much less affected. We are studying this and other grain diseases at present and may have more knowledge later on.

Loose smut, also called black head of wheat, Ustilago Tritici, was very abundant everywhere over the state in 1907. This fungus is thought to infest the seed grain, and we may therefore look to the conditions in the fall of 1906 for a part of the explanation of excessive loose smut in 1907. I suggest that the excessively favorable fall conditions of 1906 kept alive nearly every seedling plant, even though parasitized, and consequently these lived to bear black heads. I predict that a much smaller proportion will be found to have survived at harvest time in 1908.

We have successful methods of seed treatment for loose smut as well as for stinking smut, Tilletia foetens, which was also observed at several points. The stinkding smut is the more easily prevented.

Oat smut is more effectively controlled since the formalin treatment came into use, while corn smut yet resists our methods of treatment. Owing to its survival in the organic matter of the soil as well as in manure, the summer infection of new parts, rather than the seed infection, is the chief source of the disease. Something may be done by selection, although the difficulties are great. We shall be compelled to correlate all the conditions to determine whether observed variation in the amount of smut in ear-row tests is in any way due to differences in susceptibility or resistance.

DISEASES OF FORAGE CROPS.

I have mentioned earlier the killing of red clover seedlings by frost and the serious alfalfa troubles from physiological breakdown. I should add that red clover anthracnose, Colletotrichum trifolii, has spread over the southern one-third of the state and this disease has destroyed many of the young clover plants since harvest time. I believe that we have other diseases associated with the anthracnose on red clover and it is difficult at this time to determine which is the most serious. You can aid by observations and specimens. Apparently, while this fungus attacks alfalfa and has been collected on alfalfa at Wooster, it does not attack alsike clover; and mixed seedings of red and alsike clovers may be desirable for a time.

MODIFICATIONS OF BORDEAUX MIXTURE.

The high prices of copper sulfate in the earlier part of the season of 1907 ld several persons to write to the station seeking advice as to the possibility of cheapening the spray; the discussions of one year ago upon the matter of reducing the amount of copper sulfate for Bordeaux mixture used upon apples emphasized the question to which Prof. Gossard's results from the use of soap as a sticker in grape spraying brought still more data. The writer gave a good deal of attention to the considerations involved in modifications of our standard Bordeaux mixture. These various matters may be covered chiefly in three

considerations:

First-If practicable, such modifications should hold the cost of the efficient spray as low as consistent with efficiency.

Second-To be of most effect it would appear that an additional compound which should serve as a dilution-sticker, thus combining the valuable charac

teristics of the soap sticker, would be more advisable than a mere dilution of the standard Bordeaux mixture.

Third-This dilution-sticker or other compound should be of such character as to be readily obtainable and preserve its characteristics in the presence of the lime added in the ordinary spray.

As pointed out in a paper read before the October field meeting of this society, Bordeaux mixture, in my judgment, owes its relatively high efficiency as a fungicide to the insolubility or slow solubility of the copper hydroxid, which is its essential constituent. Then it is proper to keep in mind in all modifications these essentials of the original Bordeaux mixture principle. A simple reduction of the strength of the mixture is the simplest method of all to cheapen the mixture or possibly reduce russeting effects as on apples, yet the slow progress made in this direction in the past fifteen years, in spite of many suggestions offered, would indicate that a better method may be required. The writer has considered a large number of substances that might meet the severe conditions of being cheap, of sticker character, and precipitated in suitable form in the presence of lime. The dilution-sticker addition to Bordeaux, as in the case of soap, reported by Prof. Gossard last year, would serve the purpose of increasing the mass of the suspended precipitate, in which the copper hydroxid would be distributed and suspended by agitation of the liquid, and may serve also to increase the efficiency of the spray by prolonging the period in which the copper compound would remain available to the atmospheric solvents. Thus a much less amount of copper might be made actually more efficient than a larger amount without the sticker.

Of those compounds considered the most advantageous, before trial, seemed to accrue to the well-known copperas or iron sulfate. Its points are:

First-It is very cheap, being produced as a by-product in wire fence man

ufacture.

Second-Iron sulfate forms a flocculent hydroxid, which serves or may serve well as a sticker.

Third-As with copper, this hydroxid is formed in solutions upon the addition of an alkali or alkaline earth, such as lime.

By trial during the summer these characteristics appear to be such in the Bordeaux modifications. It was not a favorable season for the test of a new form of spray, yet some features may have been brought out. Before stating the details, I wish to be understood as presenting this matter in the light of an experiment possibly worthy more extensive trial. It is clear that the fall in the price of copper and of copper sulfate leaves the need for such practical modifications of much less urgent character than a year ago.

Letters were sent last spring to a few apple growers and to a limited number of grape growers, suggesting the trial of what was then called iron Bordeaux mixture in comparison with standard Bordeaux mixture. Later similar tests were made on potatoes. The following formulae were suggested:

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*The same strengths were tested on potatoes. The stronger formula was for check purposes. The real test was the weaker, or 2-4-6-50 one.

In Lorain county trials by the entomologist replaced only one pound blue vitriol with iron sulfate.

57-B. of A.

Upon apples a few lots of Baldwin trees with fair fruit crop were sprayed respectively with soap Bordeaux, iron Bordeaux and standard Bordeaux under direction of Mr. Ballou. He finds no sufficient data for statement as to relative effects of the sprays. President Cox kindly made application of two sprays standard and iron Bordeaux; he is unable to find conclusive evidence of superiority, though I judge the results were satisfactory. I judge irregularity of crop made conclusions of uncertain value. President Cox writes: "I do not like the color of the foliage sprayed with the iron Bordeaux, but it stuck all right." On the matter of the color of the iron Bordeaux spray, I confess that it is very rusty-colored. The covering or spreading of this spray here was superior to the standard Bordeaux, while possibly not equal to the soap Bordeaux. All operators whom I have consulted, report the spreading of the modified spray very satisfactory.

Upon grapes Prof. Gossard finds this modified spray of apparent value in holding arsenical compounds, being less open to market objections than the soap addition. The vineyardist reports unexpected corrosion of the wires where the iron Bordeaux was used.

Upon potatoes the results are somewhat inconclusive. In brief, they are that two pounds of copper sulfate in this modified spray gave about the same results as four pounds of copper sulfate did and both these gave better résults, apparently, in 1907 on potatoes than the strong 6-6-50 Bordeaux. I may add in conclusion that this modification of Bordeaux mixture by reducing the amount of copper sulfate to two pounds in 50 gallons and replacing the omitted sulfate of copper with two to four pounds of iron sulfate or copperas, appears well worth careful experimental test, since the cost of the spray may thereby be reduced almost one-half and its period of adhesion be extended.

I have found upon looking over the literature that a similar spray was tried many years ago successfully upon grapes in Italy. I emphasize again the fact that iron sulfate is not a fungicide, but simply a sticker, like soap might be, but at one-fifth the cost. The writer, in proposing this modifictaion, did not do so with the idea that it will be superior to standard Bordeaux, although it seems to be in grape spraying; rather with a view to testing whether it be not equal to the standard spray and at a greatly reduced cost for material.

The President: Have any of you questions to ask in regard to this? Mr. Shively There seems to be a varied opinion as to the responsibility for the destruction of our trees in the last year or two. We still know the result of the October frost of 1906, and it has been a question with us whether that frost was responsible entirely for the destruction of the trees following. In our section we feel that while it is responsible to some extent, we feel that the extreme cold weather following the warm weather we had in January, which revived the sap flow, placed the trees in a certain condition, so that the following frost affected them so, and that this was responsible to a great extent. And later on we had the same conditions in February following the warm spell in January; we had it severely cold, then another warm spell in February with severe cold afterward. This last year our light crop was confined almost en tirely to the southeastern quarter of all of the trees, almost to a line. All the fruit that we secured was on the southeastern part of those trees. Now it is a question whether it was the result of the October frost, or the re

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