TWENTY-NINTH FRUIT-GROWERS' CONVENTION. 



167 



operations which might be quite successful and satisfactory in one part 

 of the territory could not reasonably be expected to be satisfactory in 

 all its parts. The necessity of considering these conditions was clearly 

 shown in the spraying experiments of this season. 



General Principles Governing the WorJ:. — The opinion of most investi- 

 gators is that the most effective time to spray for this pest is when the 

 blossom petals have fallen and the young fruit is still upright. The theory 

 underlying this recommendation is that at this time we may place a 

 small amount of poison in the blossom cup, and the calyx lobes closing 

 together later on will retain this poison ready to be eaten when the young 

 worm enters the fruit. This, of course, presupposes that many, if not most, 

 of the worms will make their entry at this point. This principle is so 

 strongly insisted on in much of the literature on the subject that the 

 time of many of our first sprayings was governed by it. When, in our 

 experiments, we began operations at this time we usually made our sub- 

 sequent operations follow at intervals of from three to four weeks. In 

 other experiments the timing was not based on this idea. Indeed, we 

 have aimed in the work to begin operations at various periods in the 

 development of the fruit, for the very purpose of determining the sound- 

 ness of this and other theories and the value obtained from greater or 

 less numbers of sprayings. To illustrate, we have sprayed some orchards 

 at the time the petals have fallen and at intervals of from three to four 

 weeks thereafter until these orchards have been sprayed five times. On 

 other orchards our experiments have been begun from twenty to twenty- 

 five days after the petals had fallen, and on others work began forty 

 and sixty days after this had occurred. Under this system we have 

 orchards that have been sprayed five, four, three, and two times, the 

 last spray being, in each of these cases, put on from three to four 

 weeks before the fruit was picked. On other orchards spraying ceased 

 in some cases forty, in others sixty, and in others ninety days before 

 picking. By these methods the comparative value of early and late 

 spraying may be demonstrated, and also the comparative value of many 

 and few sprayings. Indeed, we have endeavored to experimentally 

 prove the value of few and many sprayings and of early and late spray- 

 ings under all the climatic changes to be found in the territory where 

 these experiments were conducted. 



Machinery and Devices Used. — It was early recognized that the time 

 of application of the spray used was but one of the many problems 

 which confronted us in the work, and that the method of application 

 was of large import in the matter. We have, therefore, carried on 

 many experiments with different pumps and spraying outfits, both 

 hand and power, and with many makes of nozzles. We have also had 

 made numerous devices, suggested from our field experience, looking 



