INSECTS AND DISEASES 



39 



Anrnrafnose CatiKer 



Bean Poi 

 Ca|- Across 



(b) Boil 1 pound of white arsenic In 2 gallons of water 

 for one-half hour and use the solution while hot to slake 

 2 pounds of good, fresh quicklime. Add water to make 

 2 gallons of stock solution, and use 1 or 2 quarts of this 

 to 50 gallons of water or Bordeaux mixture. 



(c) Slake 2 pounds of good, fresh quicklime and add 

 water to make 2 gallons of milk of lime. Add 1 pound of 

 white arsenic 



and boil hard 

 for forty min- 

 ut es . Add 

 water to bring 

 the resulting 

 compound up to 

 2 gallons. Use 

 1 or 2 quarts of 

 this stock solu- 

 tion to 50 gal- 

 lons of water or 

 Bordeaux. 



London Pur- 

 ple. — This is 

 used in the 

 same propor- 

 tion as Paris 

 green, but as it 

 is more caustic 

 it should be ap- 

 plied with two 

 or three times 

 its weight of 

 lime, or with 

 the Bordeaux 

 mixture. The 

 composition of 

 London purple 

 is variable, and 

 unless good 

 reasons exist 

 for supposing 

 that it contains 

 as much arse- 

 nic as Paris 

 ■ green, use the 

 latter poison. 



There are many proportions in which the ingredients 

 are combined to make Bordeaux mixture. The 6-4-50 for- 

 mula is not now often used, as the amount of copper 

 sulfate (or blue-stone) is greater than need be. The 3-4-50 

 formula is now much used. 



Make stock solutions by dissolving 1 lb. sulfate to 1 gal. 

 water in a barrel ; and by dry-slaking the lime and then 



Anrhracnose Spores 

 muct; maqnifiecix^ 





JSeedCoat" 



Starcli Gi-aias 



Fig. 58. How a fungus works in a bean pod. To the left above is a diagram of a section across a bean pod 

 flirough an antliracnose canlser. The large drawing below is a much enlarged view of a part of this same 

 section. It is largely diagramjnatic. It shows how the mycelial threads of the fungus may penetrate the 

 seed-coat and enter the starchy tissue of the seed, there to remain dormant until the following season. 

 On the left of the large drawing is shown a spore germinating and penetrating the epidermis. This germ- 

 tube branches, spreads through the tissues of the pod and so gives rise to a new spot or canker. To the 

 right above is shown a magnified view of some of the spores of the anthracuose fungus. One has germi- 

 nated. (After Whetzel.) 



Do not use London purple on peach or plum trees unless 

 considerable lime is added. Once much used. 



Hellebore. — BVesh white hellebore, 1 ounce ; water, 

 3 gallons. 



Apply when thoroughly mixed. This poison is not so 

 energetic as the arsenites, and may be used a short time 

 before the sprayed parts mature. For insects which 

 chew. Much used for currant-worms. 



Fungicides. 



The Bordeaux mixture, with variations in the propor- 

 tion of water to suit the particular kind of plant and 

 grade of development of the crop and of the disease, has 

 become practically the universally used medium for 

 spraying purposes. The standard formula is as follows : 

 Copper sulfate, 3 to 6 pounds ; quicklime, 4 pounds ; 

 water to make 50 gallons. 



This solution is often used successfully at half strength 

 on delicate foliage. The solution of copper sulfate is some- 

 times used without the lime on diseases of woody parts, 

 such as apple canker and anthracnose of raspberry canes. 

 In case of such use, the spraying must be done at a time 

 before the foliation begins. 



The Bordeaux mixture may be combined with Paris 

 green and other arsenites, as explained under those heads 

 on the preceding page, and thus destroy both insects and 

 fungous diseases at the same time that the caustic or 

 injurious effect of the arsenic is lessened. 



adding water till one gallon holds 1 lb. lime. Dilute these 

 stock solutions before they are put together. 



There must be lime enough to kill the caustic action of 

 the copper sulfate. This may be tested by dropping a 

 solution of ferrocyanide of potassium on the surface of 

 the Bordeaux mixture: if the drops turn brown or red, 

 more lime should be added. 



Ammoniacal Carbonate of Copper.^-Copper carbonate, 

 5 ounces ; ammonia (26° Beaumg), 3 pints ; water, 45 

 gallons. 



Make a paste of the copper carbonate with a little 

 water. Dilute the ammonia with 7 or 8 volumes of 

 water. Add the paste to the diluted ammonia and 

 stir until dissolved. Add enough water to make 45 gal- 

 lons. Allow it to settle and use only the clear blue liquid. 

 This mixture loses strength on standing. For fungout 



Copper Sulfate Solution. — Copper sulfate, 1 pound; 

 water, 15 to 25 gallons. 



Dissolve the copper sulfate in the water. This should 

 never be applied to foliage, but must be used before the 

 buds break. For peaches and nectarines, use 25 gallons 

 of water. For fungous diseases, but now largely supplanted 

 by the Bordeaux mixture. A much weaker solution is 

 recommended for trees in leaf. 



Potassium Sulfid Solution. — Potassium sulfld (liver of 

 sulfur), J to 1 ounce ; water, 1 gallon. 



This preparation loses its strength on standing, and 



