NEW YORK EXPERIMENT STATION BULLETINS. 363 



fruits commonly grown which has not several enemies that do serious 

 damage. 



The substances which are applied for the protection of foliage and fruit 

 may be divided into two classes: 1st. those which are directed against 

 fungi; 2d, those directed against insects. It is the common practice to 

 apply these separately, since when combined they are supposed to have an 

 injurious effect upon the plant. The value of a combination which would 

 be equally effective against insects and fungi can hardly be overestimated 

 for it would do away with almost one half of the operations which are now 

 necessary to obtain a good crop of fruit. 



Early in the year a series of experiments was planned to determine 

 what the action of various combinations would be upon plants, fungi, and 

 insects. Careful notes were taken at regular intervals, and I am under 

 obligations to Professor Ckeelman of the Agricultural college of Missis- 

 sippi, who was with us during the summer, for assistance in this respect. 

 The results obtained are undoubtedly more accurate than they would have 

 been had only one observer taken them. 



The compounds of copper are probably the most valuable for destroying 

 fungi, and these were used for that purpose in the combinations. The 

 arsenites are the most effective substances for the destruction of insects 

 and they were applied in connection with the fungicides. 



Every solution which is applied in a spray against fungi or insects 

 should, so far as possible, possess the following qualities: 



1. It must be effective. 



2. It must not injure the plant. 



3. It must be easy to apply. 



These essential points were kept in view when making the formulas, for 

 every solution which does not possess them must be more or less imperfect. 

 All the liquids were more easy to apply than the Bordeaux mixture. 



The arsenites used were Paris green and London purple. Equal 

 amounts of these were applied in many cases so that a comparison could 

 be made. The London purple contained 72 per cent, of the normal 

 arsenite of calcium, over 50 per cent, of which was soluble in water. 



Paris green and London purple were not applied stronger than is recom- 

 mended, except in the case of the peach. Larger quantities of the London 

 purple may have been used in a few cases, but practically all injury which 

 resulted from the applications, with the exception of the peach in some 

 cases, must be due to the fungicides, or to the united action of the insect- 

 icide and fungicide. 



The applications were made to branches of apple, peach, quince, and 

 grape; rows of potatoes and egg-plants were used, others being kept as 

 checks. Only three applications were made to egg plants; this was more 

 than was required to destroy the insects. The foliage of the potatoes 

 began to die about the middle of August, so that no definite observation 

 could be made later. All applications were made with a knapsack pump 

 and Vermorel nozzle; the combinations were mixed immediately before 

 being applied. 



None of the plants were attacked by fungi except quinces, so that it was 

 only upon these that some of the combinations could be tested as fungicides. 

 Potatoes and egg-plants were used to determine what action the combina- 

 tion would have upon insects. 



The intention was to spray about every 10 days, but as much rain fell 

 in July the applications were made more frequently. Heavy showers 



