What Is New In Spraying

A SYMPOSIUM BY PROFESSORS PETTIT, WHITE AND EUSTACE.

Introductory Remarks by Professor Pettit.

Friends—I should like at this time to make a plea for the old home-made lime and sulphur. Eight or ten years ago—yes, even five or six years ago—a good strong spray of home-made lime and sulphur used to take care of the bud moth, the pear psylla., and used to greatly re-duce the numbers of plant lice. Today, with our present practice, using the commercial lime and sulphur cold, the bud moth is affected little or none at all and the plant lice appear in due time in spite of the spray.

Voice—We do not use the commercial spray but do use the home-made lime and sulphur put on cold.

Professor Pettit—On parts of trees that we sprayed with the old home-made preparation the eggs of plant lice hatched all right but the young did not settle down. The coating of sludge seems to prevent them from settling down and starting house-keeping.

Professor Pettit—Are you familiar with the action of lime and sulphur on a scale insect? It takes the oxygen from under the scale and then seals the scale down smothering the little insect that is hidden under the scale. Now, I am speaking for home-made lime and sulphur merely as a spray for scale and not as a fungicide. When lime and sulphur is used as a fungicide the commercial article may be better than the home-made for all I know. The advantage of the sludge in the home-made spray is that it gives body to the mixture and makes more of it stick around the edges of the scales. When you paint a house you use oil and turpentine and then put in lead for the body. The oil and turpentine would do some good but with the lead added it sticks much better and more of it stays where you put it. Just so the sludge holds more lime and sulphur solution in contact with the insects. It also stays on better.

A Member—How do you regard the old way of preparing lime sulphur -15-20-50–that makes a flaky whitewash? The last few years we have used a concentrated article and we did not try to get rid of the sludge. When I make up a batch of the stuff I run the whole thing through the screen into the barrel, and when we wanted to-use it then we shook up the barrel. I have found this, that where an excessive amount of lime was used as in the old-fashioned manner of preparing it, it makes a flaky whitewash. The sludge as prepared under a concentrated formula makes a sort of paint that sticks on to the tree and turns the water off. In this respect it is better than the old whitewash.

Question—Do you put it on cold?

Answer—Yes, though that is not always expedient, it is at times more convenient. The main fault that I have with it is that it does not spray well when cold. There are little spots that it does not cover.

Professor Pettit—In washing dishes, hot ,water is better than cold and just so it is with the spraying. Warm water will spray better than ice cold water.

Question—What about the plant lice?

Answer—A tree well coated with sludge seems to prevent the young from settling. The eggs some of them hatch but the young do not seem to be able to start feeding. Perhaps they become weakened by the spray. At any rate trees sprayed with lime and sulphur in which there was plenty of sludge have less plant lice later in the season than those unsprayed.

Prof. White—Ladies and Gentlemen, Members of the Horticultural Society :

My part in this discussion is to talk a little about the control of the apple scab and the effect of lime-sulphur and Bordeaux mixture and then a little about the control of the peach leaf curl.

This past season has been an exceptional year for apple scab. There has been a great deal of moisture and conditions have been unusually favorable for its growth. Many people who have sprayed have had the apple scab and sometimes almost as bad as in orchards that have not been sprayed. I have seen a great many instances of this throughout the state this last summer. Where lime-sulphur has been used, the commercial lime-sulphur at various strengths ranging all the way from 1-25 to 1-50, I have seen no apple scab on some of the most susceptible varieties we have, like the Winter Banana, Snow, McIntosh, Red Canada, etc.—just as clean as you could have made them if you had washed them with lye. I have tried to find out what the difference was between apples that were sprayed well and those that were not, to find out why, where people had sprayed, there was still the scab as well as where they had not sprayed. What was the difference? There was evidently a mistake made somewhere and where was it made? They had either failed to spray at the right time or they had not been thorough. That may seem contradictory to some of you men’s experience but as I said before, I have seen so many instances all over this state where lime-sulphur has controlled the apple scab on many of the worst varieties that we have that I feel that where spraying fails to do the work, faulty spraying must be the cause. I call to mind an instance in a northern county where lime-sulphur and Bordeaux were used in the same orchard on the same days by the same men applying them and with the same spray outfit. Conditions were the same, except that some trees were sprayed with lime-sulphur and some with Bordeaux mixture, 4 pounds copper sulphate, 5 pounds lime, to 50 gallons of water. In so far as it was tried, the lime-sulphur showed just as good results as the Bordeaux mixture. I am very sure from an experience of the past two or three years, that commercial lime-sulphur, thoroughly applied and at the right time, will control the apple scab and I am going to recommend to every fruit grower in this state that asks me about the value of lime-sulphur as compared with Bordeaux for apples, that lime-sulphur used as it should be, will do the work. But I will not say, how-ever, that it is better than the Bordeaux or that the Bordeaux is better than it is but it is more convenient to use. There is no wearing out of nozzles or of cylinder plungers, etc., as with Bordeaux mixture.

I have in mind one orchard of 70 acres where a man attempted to spray with two power outfits. One of these outfits failed to work, consequently that whole 70 acres had to be sprayed almost entirely with one power outfit. They began on the same side of the orchard each time and when they had finished the orchard it was eight days later. Every one of you would agree with me if you had seen that orchard, that it was an easy matter to notice as you went through the orchard, the effect of the the first, second and third days, the work showed up all right but then one began to notice that the scab grew worse. Where the apples were sprayed on time, there was no scab. Where the apples were sprayed on all sides and almost at the right time, there was but little scab, but later, the scab began to appear and for this reason : The apple scab comes from a little fungus that reproduces itself by spores and if that apple fruit or apple leaf is not completely covered and kept covered with lime-sulphur or with Bordeaux mixture—if they are not covered before the spore of the apple scab germinates, I think you may rest assured that the scab will not be controlled. The point is, we often wait a few days too late and the apple scab has gotten underneath the skin and then the application of spray does no good.

A Voice—What is just the right time?

Answer—From what observations we have had, we would begin on Canada Red, Winter Banana, etc., when the blossoms are 3/4ths or 4/5ths fallen. I see no danger of destroying any bees at that time and if weather conditions are favorable to the apple scab, and you do not spray it as early as that, you will have trouble. Unless you do so early enough so as to keep the little apples completely covered, the apple scab will get the start of you and you can’t help it. Keep the fruit .. covered that is the secret of it.

This year some of the spray was washed off or it rained so that you could not spray when you should and for this reason, many had the apple scab. The point I want to make is this, it is not the failure of the Bordeaux mixture or of the lime-sulphur but it is all on our part and for the two reasons I have given.

We can use any standard commercial brand with safety, one. to forty. Mr. Welch of Douglas reports that he used home-made concentrated at slightly weaker strength than that and got very satisfactory results.

A Member—If you have any chance of having a cold May, would it not be a safe thing to spray just before the bloom?

Answer—Yes, under ordinary weather conditions you should spray first, just before the blossoms opened, second just after the blossoms fall; third again in 10-14 days and then about the first week in August. In the second summer spray, you must begin to spray before all of the blossoms have fallen from the tree, because the middle blossom of the cluster comes out and opens and drops its petals before the others have completely developed and if you wait until all the blossoms have fallen, some of this first fruits will have the scab started and that is where you get bad results. Do not think you can wait for all varieties to get in shape for spraying at one time. I have in mind two men who went into the orchard renting business and they had an orchard of Spies, Early Harvest, Maiden Blush, Red Astrachan, Ben Davis and some other varieties. They were as fine trees as you ever saw but they waited to spray the whole orchard until the Spies were ready. That was wrong and of course, their spraying did but little good. I remember a season when we got the spray on the west side. of some McIntosh trees, then waited for two days for the wind to be favorable for the east side and there was scab on the one side while on the other there was none at all.

Question—Suppose we were having a rain storm at that time. Would you go on and spray?

Answer—Yes, just as soon as possible.

Question—Is lime-sulphur a better fungicide with the arsenate of lead or without?

Answer—Yes, it is, although I would not say it is much better. Arsenate of lead has some fungicidal value in itself.

Question—Is there any advantage in using Bordeaux mixture before blossoms open instead of lime-sulphur?

Answer—I could see no reason why such a practice should be fol. lowed. Then too, russetting is just as apt to occur before the blossoms open as after they fall.

In a season where apple scab is so severe, I do not mean to say that the ordinary number of four summer sprays will absolutely control scab, because in the rainy weather a good deal of the spray will be washed off or diluted. I do not know that it is always economical but under such conditions, it is no doubt necessary to do more spraying in order to completely control it. Perhaps make an extra application or two.

A Member—I have lost some snow apples. I got through spraying for the codling moth as I supposed—my snow apples were perfectly clean. It was not yet time to spray for the second crop and right in them my snow apples scabbed up. I think if I had put in one more spraying, I would have saved those snow apples.

Answer—In other words, if you had kept the fruit covered you would not have had the scab.

A Member—What about spraying for the peach leaf curl?

Answer—We have depended for a good many years upon Copper Sulphate solution, 2½ to 4 pounds Blue vitriol crystals dissolved in fifty gallons of water to control peach leaf curl. This was applied before the peach buds swelled and was used almost universally until San Jose scale came into southwestern Michigan. The reputation of lime-sulphur as a fungicide as well as an insecticide made orchardists there wonder if they could not depend upon their spray for scale to control the curl leaf also. It was demonstrated that a 15-25-50 formula, boiled and applied hot would do the work all right. Then the commercial lime-sulphur came and fruit growers used it for scale and found that that would control the leaf curl if applied early enough in spring. Thus the spray of copper sulphate for leaf curl was eliminated where spraying for scale was necessary. –

But where spraying for scale was unnecessary, there has been considerable discussion as to which was best, strong copper sulphate solution or Bordeaux mixture and whether a weaker mixture of commercial lime-sulphur could be used satisfactorily or not. At the last meeting of this Society and at many Farmers’ Institutes through the state last winter, speakers recommended Bordeaux mixture as the only spray for curl leaf. I could see no particular advantage in using Bordeaux in preference to copper sulphate and had much confidence in lime-sulphur. I wanted to settle this dispute so I arranged for a comparative test of copper sulphate solution 2½, pounds to fifty gallons of water and commercial lime-sulphur 21/2 gals. to 50 gallons of water at Hart on the farm of Benton Gebhart. The varieties selected were Elberta, Francis and Engles Mammoth. Two rows of trees crossing the blocks of these three varieties were sprayed with lime-sulphur. On either side of these two rows copper sulphate solution was used.

When Professor Eustace and I visited the orchard about the first of June, just as curl leaf was stopping, we could detect the rows of trees sprayed with lime-sulphur as easily as could be. The results were exceedingly plain and the lime-sulphur had almost absolutely con-trolled the leaf curl. Hardly a leaf in a thousand was affected while beneath the copper sulphate sprayed trees there were many leaves which had curled and dropped.

Question—What time did you put that on?

Answer—Before the buds swelled in the spring about the first of April. Many fail by waiting until the buds have swelled and the little leaves appear. That is decidedly too late, for curl leaf will be already intrenched if weather conditions are at all favorable. Now copper sulphate solution costs about 12½ to fifteen cents per bbl. of 50 gallons. Bordeaux about 25 cents and lime-sulphur 2½ to 50 about 23 cents. You can take your choice.