the grape grower to apply the remedies in time to save the fruit. In the leaf stage it shows itself as little reddish spots, which when examined closely, especially by means of a magnifier, will be found to possess numbers of minute black pustules, the pycnidia. The various mixtures described above, containing copper sulphate are quite successfully used against this dis ease. APPENDIX III. Below will be found an account of some experiments conducted at the station at Pine Bluff, and a letter from Mr. Sol Franklin giving his experience in fighting the worms, which we deem of sufficient importance to warrant publication. POISONING THE COTTON CATERPILLAR. An examination of the under surface of the cotton leaves in the last week in August, discovered many moth eggs, and a few very small worms. By September 6th a majority of the eggs had hatched, and an examination at this date discovered many worms and a very few eggs. By September 9th the young worms which had hitherto remained on the under surface of the leaf began to eat through the leaf and make their appearance on the upper surface. This was thought the proper time to poison and on the 10th a mixture of one pound of Paris Green to one of flour was dusted on. It was applied in the simplest possible way, a man on horseback riding between the rows and striking a stick, to each end of which was tied a sack of poison, on the pommel of the saddle. The application of poison was almost completely successful. The day after poisoning a good many dead worms could be found on the ground. Three days after, live worms could be found only on occasional stalks that had not received their full share of poison. The application of poison did not perceptibly affect the growth of the plant, the cotton continuing to grow and bloom and set its bolls until killed by frost. EXPERIMENTS WITH POISON. Object: To ascertain the best form in which to apply poi son. Six rows were used for each experiment. The poison for these experiments was applied on the 11th of September. Plat 1. No poison. Plat 2. Paris Green in water, one half pound to forty-eight gallons of water, sprayed on. Plat 3. No poison. Plat 4. Paris Green dusted on. Plat 5. No poison. Plat 6. ted on. One part of Paris Green to five parts of flour dus Plat 7. No poison. Plat 8. One part of Paris Green to ten of flour dusted on. The day after poison was applied enough rain fell for water to stand in the rows. A week after there was a very perceptible difference in the degree of protection afforded by the different forms in which poison was applied. The rows to which Paris Green mixed with flour was applied, received nearly complete protection, while those to which Paris Green alone and Paris Green in water received only partial protection, fully one half of the foliage being destroyed by the worms. The plats which were not poisoned were completely stripped. These experiments go to show that Paris Green mixed with flour is more difficult to wash off than Paris Green alone, or mixed with water, and that for this reason, if for no other, poison should be mixed with flour or some other sticky substance, that will cause it to adhere to the leaves and resist washing. GENERAL REMARKS. If the poison is applied at the proper time, and there are no heavy rains immediately after poisoning, the ravages of the cotton worm can be prevented. That the cotton crop can be saved under these conditions has been established beyond all question. The proper time to apply poison, is when the worms of the third crop are beginning to eat through the leaf and make their appearance on its upper surface. To know exactly when this time comes will require continuous watchfulness on the part of the planter. After the moths have made their ap pearance in large numbers a close watch should be kept on the cotton field. During the first ten or twelve days of their existence the young worms remain on the under surface of the leaf, and during this time the leaves should be examined at least twice a week and every day if possible. The planter who will watch his field closely, and poison when the young worms are beginning to make their appearance on the upper surface of the leaves, can hardly fail to succeed. The second crop is seldom sufficiently large to do serious injury save in particular fields or low spots. These particular fields or low spots should be closely watched, and poison applied if the worms appear in sufficient numbers to justify it. We can not too strongly emphasize the necessity of continuous watchfulness from the time the worm first makes its appearance, until all danger is past, for upon this watchfulness and the ability to apply poison at a moment's notice will depend success in preventing the ravages of the worm, A. F. CORY. NOBLE LAKE, ARK., Jan. 17, 1890. C. W. WOODWORTH, DEAR SIR:-The cotton worms were first seen in this neighborhood about the 23d of July, 1889. The first crop was only in spots and very few. They webbed up but did no harm. Three weeks from that date, about the middle of August, the second crop was discovered in patches, (different parts of the place) in one to five acres in a place. As soon as they commenced to work I used three of Jas. P. Roaches' cotton worm destroyers, in which I used London Purple as a poison, in powder. This machine will powder from eight to ten rows at a time and from 70 to 80 acres per day. By using this machine it will take one and a quarter to one and a half pounds of poison per acre. I applied the poison on the second crop where the worms were first noticed, and thinking they would become general I powdered all of my cotton and used all the poison I had except about 400 pounds. After this, quite a number of the second crop webbed up again, and fearing they would appear again, I purchased 1000 pounds of Paris Green. I experimented by mixing thoroughly, 400 pounds of London Purple with equal amount of Paris Green. Then the last or third crop made their appearance about the 2d of September. Then I applied with the machines, the mixture of London Purple and Paris Green with great success, effectually destroying the worms and saving the crop. In many places the worms had just commenced to eat the top crop. I then run the machine over them and killed them almost instantly. The cotton kept growing and fruiting to the very top of the stalk until frost, about the 8th of November, and after frost nearly all the matured bolls opened and made good cotton My experience with the London Purple used by itself, is not as effectual as being mixed equally with Paris Green. Besides reducing the cost-as the London Purple is as cheap again as the Paris Green. Where the poisons were not used on the cotton, the worms fully destroyed all the top crop and a portion of the middle crop. In regard to the field lamps, I would state that they proved to be a failure. We put them out about the 5th of July and kept them burning until the 20th of August. We caught a number of flies during the month of August, but to no purpose. It might have been that we commenced burning the lamps too late, as I learn the people in Texas commenced burning the lamps about the 1st of June. Besides, or even if the lamps could be used successfully, the whole neighborhood would have to use them, or unless they did it would be of no Yours very truly, use. SOL FRANKLIN. |