BULLETIN ]N"o. 201. 



DEPARTMENTS OF CHEMISTRY, ENTOMOLOGY AND 

 BOTANY. 



INSECTICIDES AND FUNGICIDES 

 FOR FARM AND ORCHARD CROPS IN MASSA- 

 CHUSETTS. 



BY E. B. HOLL.\ND, A. I. BOURNE AND P. J. ANDERSON. 



The successful production of farm and orchard crops depends in large 

 measure on the protection afforded against injurious insects and bacterial 

 and fungous diseases. Obviously there is no remedy — that is, no panacea 

 for all noxious insects and parasitic diseases of plant life — that would not 

 also destroy the host. The method of treatment, therefore, must be 

 essentially specific, and for convenience will be divided into three major 

 groups: (A) Insecticides, (B) Fungicides, and (C) Combined applications. 



A. INSECTICIDES. 



The injurious insects that infest the crops under consideration are of 

 two distinct types as determined by their mode of feeding: i.e., biting 

 and sucking. The former type consumes organized tissue, and the latter 

 draws sustenance from plant juices. The respective treatment of the two 

 tjTjes is necessarily different and warrants a division of insecticides into 

 (I) Stomach poisons for biting insects, and (II) Contact poisons for suck- 

 ing insects. The stomach poisons of to-day owe their origin largely to the 

 Colorado potato beetle, and the contact poisons to the San Jose scale. 



The acknowledged requisites for an insecticide are — 



1. Non-toxicity as to plant. 



2. Effectiveness in destroying the insect. 



3. Adhesiveness or persistence under all weather conditions. 



4. Fineness of particles and a light flocculent character (when insoluble) to insure 

 a high power of suspension and uniform distribution. 



5. Ability to indicate the surface covered. 



6. Reasonable cost. 



