14 N. H. Agr. Experiment Station [Bulletin 289 



greater amount of nitrate nitrogen in the soil under the mulched trees in 

 mid-summer must be caused by leaching of nitrate down from the decaying 

 mulch. On August 1, for example, the parts of nitrate nitrogen per million 

 on the dry basis showed 41.36, 77.94 and 67.57 for the mulched trees and 

 4.41, 2.32 and 3.50 for the non-mulched. 



Tests to determine the nitrate nitrogen in the soil below the mulch level, 

 taken on October 23, showed that the upper two inches contained the most, 

 with a decrease with each deeper sample. 



When the apples were harvested the fruit from the mulched trees was 

 not quite so green on the average as the fruit from the unmulched trees, and 

 the per cent of bitter-pit was also lower. Sample boxes of the fruit harvested 

 from each tree were placed in common storage and were subjected to the 

 pressure test when placed in storage and at intervals until March 14th. The 

 fruit from the mulched trees when placed in storage showed less resistance 

 to pressure than the fruit from the non-mulched trees, and the percentage 

 difference shown at that time remained practically unchanged throughout 

 the period of storage. Some bitter-pit developed in storage in the fruit from 

 the mulched and non-mulched trees, but the percentage found in the latter 

 was much higher than in the former. (0. Butler — Purnell Fund.) 



Apple Scab 



Studies of apple scab were continued on: 1. effect of pressure on con- 

 trol ; 2. effect of night versus day spraying ; 3. effect of use of one and two 

 cover sprays ; 4. effect of use of calcium arsenate in lieu of lead arsenate 

 in lime-sulphur solution, especially from the point of view of spray injury ; 

 5. test of the value of Cal-mo-sul, Kolofog, and flotation sulphur. Cal-mo- 

 sul was used throughout the spray schedule, Kolofog beginning at the pink 

 application, and flotation sulphur beginning at the calyx. Satisfactory con- 

 trol was obtained with all these materials, but scab infestation was not 

 sufficiently severe to adequately test them. 



Two cover sprays gave better control than one cover. Spray injury on 

 foliage was slight and not increased by calcium arsenate, and the finish of the 

 fruit on all the plots was excellent. i 



The trees sprayed at night were freer from scab than the trees sprayed 

 during the day, but the average results to date indicate that over a period of 

 years, time of spraying, all other things equal, does not materially aff'ect the 

 degree of protection afforded. 



Four hundred pounds pressure gave better control than either 200 lbs. or 

 300 lbs. pressure. However, these results seem to be purely accidental as 

 fluctuations occur from year to year. 



The data so far secured indicate that irrespective of the length of the 

 snow cover, or the mean temperature of winter, as ascospores mature during 

 the last 10 days of April, and discharge occurs during the first wetting rain 

 following maturity. The ascopores were mature April 24th, but no discharge 

 occurred in nature until May 10. The delayed discharge was no doubt due 

 to the scantiness of the rainfall. The first rain after April 24th occurred on 

 May 4th (0.02 in.) and the next on May 9th (0.37 in.) . The pre-pink spray, 

 it may be observed in passing, was applied May 5th. (0. Butler, E. J. Ras- 

 mussen, S. Dunn — Hatch Fund.) 



