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CODLING MOTH MP 1947 EXPERILSNTS ^ 



Apples in the experimental orchard at the Vifaltham Field Station had the greatest 

 infestation of codling moth in 1947 that has been recorded in 22 years - BUT ONLY IN 

 ONE BLOCK. That block was sprayed v;ith benzene hexachloride, an insecticide noted 

 for its short period of effectiveness and one v/hich is not considered especially 

 effective against this pest. The blocks where DDT or lead arsenate, either alone 

 or in combination, v/as used v;ere either entirely free or had an insignificant 

 infestation averaging less than 3 codling worn stings per 1,000 apples. 



Since all of the blocks were sprayed on the same day, vie must assume that the 

 timing of the applications in the spray schedule was satisfactory, at least where 

 DDT or lead arsenate v/as used. 



The dates of application were; 



First Cover ,.,....,....••••«• June 4 Compare these dates v/ith 



Extra Curculio ,,,.♦.,,,,,,,, , June 10 your application periods. 



Second Cover June 23 naturally allowing a fev." days 



Third Cover July 11 for climatic differences between 



Fourth Cover July 30 your orchard and Vialtham, 



Most of the worm injury occurred in July from late hatching first brood v.'orms, 

 and the sprays on June 23 and July 11 v/ere the most critical. Obviously the 

 extended periods of hot, dry v/eather favored codling moth development, but even so 

 a reasonable spray schedule should have given reasonable results, 



DDT continues to prove its effectiveness against codling moth and personally 



1 believe that a combination of lead arsenate 2 pounds, 50Jo DDT wettable pov;der 



2 pounds in 100 gallons of spray is the most effective forrnula of insecticide for 

 ALL COTOR SPRAYS. 



Could it be that the old familiar bug-a-boo of inadequate coverage is still 

 the cause of trouble? 



— W. D, Vi/hitcomb 

  =(< ***************** * 



STUDIES OU APPLE SCAB AT THE VfALTHAIvI FIEL D STATION 



Our plan of study v;as designed to clarify our knowledge of Phygon and 

 Puratized Agricultural Spray, The interest in these materials seemed dominating. 



Our v/ork in 1946 revealed the astonishing fungicidal action of Phygon, at 

 1 lb, to 100 gallons of water. Our work in 1947 gave similar astonishing results 

 in the control of apple scab with Phygon l/2 lb. to 100 gallons of water. In 

 1946, Phygon caused some degeneration of the green matter in the leaves and there 

 was indication of a decrease in size of individual fruits. This year l/2 lb, of 

 Phygon caused similar foliage injury whether one or more sprays were applied. Is 

 the injury serious? Is the effect from the pre-blossom applications more or less 

 than the post blossom applications? Can the injurious element be buffered by the 

 addition of a corrective? These are questions that only further study can answer 

 and the help of chemistry is needed. Injury to the face and heuids from contact 



