12 N. H. Agric. Experiment Station [Bui. 270 



Apple Maggot Defies Spraying 



Three years of spraying for apple maggot in orchards at Wonalacet, 

 X. H., have shown no appreciable reduction of the pest on sprayed 

 trees, reports W. C. O'Kane. The trees were given cover sprays on 

 dates determined by the time of emergence of the flies, and adjacent 

 shrubbery and trees also received the applications. In the check area, 

 where the drops were kept picked up, there was noticeable decrease 

 in infestation, especially in Mcintosh. 



In feeding experiments at Durham conducted to learn more about 

 the toxicity of arsenate of lead to apple maggot flies, the mortality of 

 the flies in the check cages frequently exceeded that of the flies feed- 

 ing on poisoned foliage in other cages. 



Additional studies are now under way in a commercial orchard 

 which had been severely infested. [Purnell Fund) 



Spray Residue Small Despite Dry Season 



Despite the unusually dry season of 1932 only a few samples of 

 apples were found to carry arsenic even slightly in excess of the tol- 

 erance, and these were selected from the lower part of the most heavily 

 sprayed trees, report G. P. Percival and G. F. Potter regarding their 

 investigations on spray residues. 



From results on eight lots analyzed before and after, the practice 

 of wiping appears effective in reducing the spray residue to a safe 

 amount. It is not recommended for apples carrying arsenic in amounts 

 greatly in excess of the tolerance. 



Three years' results of this study have been published and the re- 

 search continued on additional varieties in commercial orchards in 

 the state. Over 70 samples of apples, representing seven varieties and 

 various spray treatments, have been analyzed. {Purnell Fund) 



Control of Poison Ivy 



Discovery of anherbicide that will kill poison ivy and at the same 

 time benefit the soil is announced by 0. Butler, following experiments 

 with kainite. This fertilizing material which should preferably be 

 finely ground is broadcast on the ivy when the leaves are wet and is 

 not harmful to trees amidst which the poison ivy may be growing 

 nor to the soil. [Hatch Fund) 



Leafroll Affected by Temperature Change 



So far as mosaic is concerned, differences in temperature for growth 

 of parent potatoes and resulting seed stock are not significant, finds 

 0. Butler. In the case of leafroll, however, a well marked tendency 

 was found for plants to produce smaller tubers in successive genera- 

 tions even when grown yearty at the same temperature; and growing 

 plants at 15°C. from seed tubers obtained from plants grown at 20°C. 

 proved particularly injurious. [Purnell Fund) 



