CODLING MOTH IN SANTA CLARA VALLEY. 179 



The five sprayed trees under observation show a range in wormy 

 fruit from 6.49 to 14.27 per cent, with an average of 9.97 per cent, 

 while the five unsprayed trees ranged from 45.28 to 82.16 per cent 

 wormy fruit. 



The five sprayed trees averaged 90.03 per cent sound fruit, while 

 the checks averaged only 25.45 per cent sound fruit, the spraying 

 thus giving a benefit of 64.58 per cent sound fruit on the sprayed 

 trees. 



It is evident that the second brood of larvae caused a large per- 

 centage of wormy fruit both on the sprayed and unsprayed trees. 

 The wormy fruit on the five sprayed trees at picking time ranged 

 from 14.19 per cent, and since most of the apples affected by the 

 first brood had fallen off before this nearly all of the injury can be 

 charged to the second-brood larvae. 



CONCLUSIONS FROM EXPERIMENTS IN CONTROL. 



Two orchards, one of pears and one of apples, which had been 

 sprayed for the codling moth according to the recommendation of 

 this bureau, show conclusively the advantage derived from this 

 treatment. 



The pear orchard shows more decided results than the apple 

 orchard because of more thorough work with a power outfit at high 

 pressure. 



The second year's treatment on the pear orchard shows to advan- 

 tage because of better work and timing of the applications. 



Two years' observations have shown that three applications of 

 arsenate of lead in the Santa Clara Valley at about 2 pounds to 50 

 gallons are necessary for pears and apples, except on Bartlett pears, 

 where two would be sufficient. 



The first application should be made just after the blossom petals 

 fall, and the date may vary from early April to the first few days 

 in May, depending upon the variety of fruit and the season; the 

 second application should be made about from 2 to 3 weeks after 

 the first application, and usually falls in June; the third application 

 should be applied about from 3 to 4 weeks after the second, and 

 usually falls in July. 



Arsenate of lead can be used on pears along with the treatment 

 recommended for pear-thrips larvae, and the distillate-oil emulsion 

 seems to give the poison a smoother surface tension so that it 

 spreads more readily on the foliage and holds up longer in suspension 

 while in the spray tank. The arsenate of lead should be mixed 

 separately and added last to the spray tank after the distillate-oil 

 emulsion and tobacco extract have been combined. 



