11 X. H. Agr. Experiment Station [Bulletin 262 



of date of harvest on the development of bitter-pit during storage 

 showed that fruit harvested October 11 with uniform starch distribution 

 had only two per cent, bitter-pit by January, while fruit harvested 

 October 23 with irregular starch distribution developed 41 per cent, 

 bitter-pit. (Hatch Fund) 



Oil Sprays 



Studies of oil sprays were made by L. S. Groves to determine the 

 cause of toxicity and effect upon the sprayed plant. Highly refined 

 mineral oils suitable for medicinal use were found non-toxic to the 

 plant even when applied undiluted. Neither heavy nor light oil caused 

 any visible injury to the tissues, but both disturb photosynthetic ac- 

 tivity even when used at the strength recommended in practice for 

 highly refined petroleum oils. The effect produced increases with the 

 percentage strength in oil of the emulsion ; inhibition is virtually com- 

 plete when strong emulsions or the oils alone are applied. 



Oil sprays were also found to reduce the amount of dry matter 

 formed. 



Studies on the penetration of the leaf tissue by heavy and light oils 

 showed that penetration was more rapid from the under surface than 

 from the upper. The penetration of the oils was facilitated by the 

 presence of stomata, but they are not essential to it. Upon penetrat- 

 ing into the leaf the oils creep through the intercellular spaces which 

 they fill more or less completely. The replacement of the air in the 

 intercellular spaces by the oil, owing to the high refractive index of the 

 latter, causes light to pass more readily through the leaves and the in- 

 vaded tissues are thus rendered more translucent. The oils after pene- 

 trating the leaf soon reach a state of equilibrium and remain indefinite- 

 ly in the position first occupied. Translucent spots in leaves sprayed 

 with heavy and light oil emulsions suffer no appreciable change in 

 shape or size with time. The oil remains at the point to which it has 

 penetrated indefinitely. The rate at which heavy and light oils dry do 

 not effect the extent of penetration. 



In the studies made with kerosene, on the other hand, it was found 

 that the rate of drying does affect the degree of penetration and the 

 amount of injury ultimately produced. When kerosene is subjected 

 to fractional distillation it will be found that the injuriousness of the 

 fractions obtained decreases with a rise in the boiling point, fractions 

 with high boiling point being even less injurious than the original kero- 

 sene itself. 



Petroleum-saturated hydrocarbons with a boiling point of 180°C- 

 200°C. are only very slightly toxic, and the injuriousness of the kero- 

 sene fraction that distills between 180°C.-200°C. must be ascribed to the 

 presence of unsaturated hydrocarbons. (Miscellaneous Income) 



Leafroll and Maturity 



Leafroll tends to increase with the maturity of the seed in southern 

 New Hampshire, finds 0. Butler, continuing his study of degeneration 

 diseases of the potato. Green Mountain potatoes of the crop of 1929, 



