PROCEEDINGS OF THIRTY-SIXTH FRUIT-GROWERS* CONVENTION. 131 



weeks apart as follows: May 1st; May 15th; June 1st, and June 15th 

 to July 1st. Arsenate of lead is used with these applications at the rate 

 of 2 pounds to 50 gallons for the first two, and 1 pound to the same 

 quantity of the second two. The August and September sprayings are 

 $0 contain arsenate of lead alone. 



The iron sulphide under discussion is a complex compound formed by 

 the reaction of the lime-sulphur solution on a solution of copperas (iron 

 sulphate"). A 200-gallon quantity is prepared as follows: 



Dissolve 15 pounds of copperas in a 50-gallon barrel, two thirds 

 full of water, and then add 13 quarts of the 33-degree Baume (com- 

 mercial) lime-sulphur solution; add water to fill the barrel and agitate 

 thoroughly. A thick black precipitate is formed, and, if, as there should 

 be, there is a slight excess of the lime-sulphur solution a reddish liquid 

 will separate. Allow to settle for twelve hours and then pour off as 

 much of the liquid as possible without loss of the black precipitate. 

 Repeat the operation of filling the barrel with water, agitating, allow- 

 ing to settle and decanting, four or five times, or until the excess lime- 

 sulphur solution is washed away. When the washing is complete the 

 mixture is ready to dilute with water to make 200 gallons of spray. 

 Arsenate of lead is added while diluting, along with the water. 



When iron sulphide is used, there should be no need of the Bordeaux 

 mixture, for the results of our experiments indicate that the mildew 

 spray is also effective against the scab. In spraying for the mildew 

 special effort should be made to wet the tips of the growing shoots as 

 these parts most need protection. 



The use of iron sulphide for the mildew is just emerging from the 

 experimental stage, hut we are prepared to say that young orchards, 

 from the time of planting until coming into bearing, will be greatly 

 benefited by five or six applications, as the growth is greatly stimu- 

 lated. Older trees are also much stimulated in growth, but the first 

 application is likely to shock the tree and cause the dropping of some 

 of the young fruit. This shock is apparently due to the especially 

 delicate condition produced by bad attacks of the mildew and may be 

 expected to disappear when a normal condition of thrift has been 

 restored. 



The following points should be remembered in the use of iron sulphide 

 for the mildew : One or two applications will produce little or no effect, 

 because the infection of the young growth is continuous during the 

 growing period, and so the protection must be continuous. There may 

 be some dropping of the young fruit as a result of the use of the spray, 

 but this loss should be compensated by increased growth and vigor 

 resulting in better future crops. 



The discussion of these general methods of procedure for the control 

 of the most important apple pests is scarcely complete without con- 

 sidering some of the special problems which may come up incidentally. 

 The woolly aphis was mentioned under winter treatment, and the state- 

 ment was made that this insect might require further treatment during 

 the summer. Aphids of various species develop rapidly at times, and 

 the apple in California is subject to the attacks of at least three. The 

 woolly aphis, green aphis, and leaf-curling aphis may all become 

 abundant enough at times to inflict serious injury. These insects are 

 all soft bodied and easily killed with contact insecticides when actually 



