13 



In the case of bearing orange trees it would appear that the season 

 of the year when they could be sprayed with the least amount of in- 

 jury to themselves and with the greatest fatality to the red scales infest- 

 ing them would be at a time when they were in blossom, after all of 

 the fruit of the preceding season had been removed from them. There 

 would at such a time be no fruit on the trees for the scale-insects to- 

 locate upon, so that all these insects that could be reached by the spray 

 would be destroyed without at the same time injuring any portion of 

 the tree. Several persons who had sprayed their orange trees at a time 

 when the latter were in full bloom informed me that to all appearances- 

 none of the blossoms were injured by the spray, providing that the 

 latter was not used so strong that it injured the leaves, being unani- 

 mously of the opinion that the blossoms were as hardy as the leaves. 

 The young fruit is much more susceptible to the effects of the spray than 

 are either the leaves or the blossoms, and this is the case until it becomes 

 at least half-grown. It has been my experience, and also the experience 

 of others with whom I have conversed upon the subject, that where the 

 conditions are equal an orange tree is more susceptible to the effects 

 of a given spray than a lemon tree, the foliage of the latter being- 

 hardier; whereas in the case of frosts the reverse of this is true, lemon 

 trees being greatly injured by frosts that would produce little or no 

 effect upon orange trees growing under similar conditions. 



It is a well-established fact that any given spray will not be so fatal 

 to the scale insects during the cooler portion of the year as it will if 

 applied during the hotter portion. On this account it will evidently be 

 found necessary during the winter months to use a somewhat stronger 

 solution than indicated in the formula given above j and probably the 

 proper proportions to use during this season would be obtained by ad- 

 ding water sufficient to make only 80 gallons, instead of 100 gallons as 

 given in the above formula. 



What is true in regard to the effects of the solution upon the insects 

 is equally true of its effects upon the tree, the same solution that would 

 not injure the tree if applied during cool weather might injure it very 

 severely if applied during very warm weather. As bearing upon this 

 subject, I can not do better than to give the experience of one of my 

 correspondents, Mr. F. G-. Ryan, an intelligent orange-grower of 

 Anaheim, in the adjoining county of Orange. Mr. Ryan used the resin 

 compound quite extensively for the destruction of the Black Scale 

 (Lecanium olece Bernard), and under date of February 7, 1889, he writes 

 me as follows : 



I want to tell you of a disappointing experience I had with the resin compound. 

 On January 21 and 22 I sprayed twelve trees in one quarter of the grove and eight in 

 another with a compound composed of 1 pound of caustic soda, 8 pounds of resin aud 

 32 gallons of water. After doing this a hot, drying wind arose and stopped our work. 

 The wind continued for several days, becoming milder each succeeding day, and on 

 the fourth day I noticed some leaves dropping from these trees ; this droppiug of the 

 foliage has continued and increased until now there is scarcely half the foliage left 



