18 N. H. Agr. Experiment Station [Bulletin 313 



reversed by a downward drift of cold air which caused moisture con- 

 densation. Dry rot also developed in the potatoes. 



The experimental storage bins at the university were all of the 

 same height and capacity and provided with air intakes and gravity 

 ventilation. In Bin A, which is a new type devised at this station, 

 a false bottom of planks spaced three-fourths of an inch apart was 

 laid over the dirt floor and the air intake opened beneath it. In Bin 

 B a Maine type air conduit was run down the middle and was con- 

 nected directly to the air intake. Bin C was the ordinary type in 

 which the air intake opens onto the dirt floor upon which the pota- 

 toes were stored. At the end of 182 days the potatoes in Bin A had 

 lost 3.35 per cent of their weight, while those in BinS had lost 4.79 

 per cent. The potatoes in Bin C at the end of only 115 days had lost 

 3.23 per cent of their weight. Loss of weight in all cases was greater 

 at the bottom of the bin than at the top. {Purnell Fund) 



Masking Potato Mosaic 



Symptoms of potato mosaic which are "masked" (not readily dis- 

 cernible) when plants are grown at temperatures averaging 68 F. 

 become quite noticeable when plants are placed in a cooler environ- 

 ment of around 59 F. It has been found that fertilizer, also, has a 

 significant effect on the masking of symptoms. In this year's experi- 

 ments, in charge of 0. R. Butlei% plants were grown in a soil taken 

 from a worn-out pasture. Some were fertilized with an 8-16-16 fer- 

 tilizer, some with a mixture of 8-16-16 and cow dung, the rest with 

 cow dung and bonemeal. One series was grown at a mean tempera- 

 ture of 68 F., another at 59 F. The color of the foliage was deepest 

 green in the series fertilized with 8-16-16 and palest in the series 

 fertilized with cow dung and bonemeal. Masking of symptoms 

 occurred in the plants grown at 68 "F. and was most pronounced in 

 the series fertilized with 8-16-16 and least in the cow dung and bone- 

 meal series. 



In the growing of seed potatoes it is no advantage to have symp- 

 toms of mosaic masked; but where a grower is producing for human 

 consumption his yield will be increased when the leaves are a healthy 

 green rather than mottled and grayed by mosaic. {Purnell Fund) 



Spraying for Apple Scab 



Damp weather and other factors caused unusually prevalent scab 

 on the foliage of Mcintosh trees in the 1937 season. For the first 

 time in 15 years research workers were able to obtain data on control 

 methods for scab on foliage as well as on fruit. O. R. Butler, who 

 directs this research, found that lime-sulphur spray on the foliage 

 was much more effective than flotation sulphur. Three cover sprays 

 of lime-sulphur proved to be the most eff'ective control measure for 

 scab on both fruit and foliage. {Hatch Fund) 



Mulching as it Affects Bitter-pit in Apples 



Mulched trees averaged 25 ])ounds higher yield than uimiulched 

 trees, but the apple drop was heavier on the mulched than on the 

 non-mulched trees. Fruit from mulched trees developed about five 

 per cent less bitter-pit in storage than the fruit from the non- 

 mulched trees. 0. R. Butler directs this work : G. P. Percival was in 

 charge of the chemical phases of the experiment. {Punicll Fund) 



