THE MONTHLY BULLETIN. 265 



THE COMPATIBILITY OF INSECTICIDES AND FUNGICIDES. 



Address, California State Fruit Growers' Convention. Davis, Cal., June 1-lG, 1914 

 Geo. p. Gray, University of California. 



INTRODUCTION. 



The cost of crop pest insurance by means of spraying is no small 

 lurden to most producers, who are often confronted with the necessity 

 of making frecjucnt applications of various remedies to insure their 

 products against the ravages of insect and fungous parasites. At times 

 it must almost seem that if the necessary thought and time were given 

 to the proper application of the appropriate treatment at the right 

 time, little energy would be left for cultivation, harvesting or other 

 necessary operations. 



The cost of spray materials is no small item, but is usually insignifi- 

 cant as compared to the post of application. One way of reducing the 

 latter expense is by combination spraying, that is, by mixing two or 

 more spray materials and applying them together. In mixtures of this 

 sort, grave chemical changes may take place which render tlie mixture 

 wholly unfit for use. On the other hand, the original ingredients may 

 remain unchanged or may be improved by their new associates. 



Numerous experiments have been made to determine the advisability 

 of combination sprays, and the results have been published in the bulle- 

 tins of the United States Department of Agriculture, the state experi- 

 ment stations, and in agricultural journals. These reports are scat- 

 tered through so many publications and the conclusions are at times 

 so conflicting that no inconsiderable amount of time must be spent in 

 a search of the literature to arrive at a definite conclusion as to the 

 suitability of applying some particular remedy in combination with 

 another. 



In order to bring this information into more available form and of 

 more easy access, it has been condensed into tabular form and a com- 

 patibility table is presented for your ccnsideraticn with the hope that 

 it will be of some assistance in warning you of obscure dangers that 

 may lurk in apparently harmless mixtures. 



