March, 1938] Agricultural Research in N. H. 31 



two groups do not appear to have been described in the literature and 

 are sufficiently distinct from the other recognized forms to be consid- 

 ered distinct varieties. It has been found that the majority of the 

 streptococci enter the milk from utensils which have not been ade- 

 quately cleaned and sterilized. {Hatch Fund) 



Spraying for Apple Scab 



Seven years' study of the rate of maturation and discharge of apple 

 scab spores indicates that there is no one environmental factor primarily 

 responsible for the variations that are met with from year to year. Data 

 have been taken by Stuart Dunn and 0. Butler on snow cover, mean 

 winter temperature to April 1st, mean temperature between April 1st 

 and pre-pink spray application for scab control, amount and average 

 duration of rainfall between April 1st and pre-pink. 



During the period ascospore discharge has occurred once prior to the 

 date of application of the pre-pink spray, twice on the date of the pre- 

 pink spray, and during the remainder of the seasons in the interval be- 

 tween the application of the pre-pink and pink sprays. The stages of 

 vegetation of the tree now in use for timing the spray applications for 

 scab control are, therefore, entirely adequate for the purpose. 



Following the initial ascospore ejection, discharges occur at inter- 

 vals for about two months, but they do not occur during every rain. 

 Generally, discharges are most abundant between the time of applica- 

 tion of the pink spray and the first cover spray with the greater fre- 

 quency sometimes before the calyx, sometimes after. Usually the period 

 between the first and second cover sprays is one in wiiich the fungus shows 

 little or no activity. Relation of this data to the per cent, of scab on 

 Mcintosh indicates that the seriousness of infection in any one season 

 bears no direct relation to the number of ascospore discharges that oc- 

 curred. 



During the year in the spraying experiments on scab control, lime- 

 sulphur and fiotation sulphur were the fungicides used. In some plots 

 two. in others three cover sprays were applied. In the case of lime- 

 sulphur in some plots a spray gun was used, in others a tri-nozzle for 

 the purpose primarily of studying effect of method of application on 

 spray injury. No material difference between nozzles could be ob- 

 served as regards the effect on spray injury, but a very marked differ- 

 ence in scab control was obtained. In the plots in which the tri-nozzle 

 was used there was 9.2 per cent, scab, and in those sprayed with the 

 gun 45.3 per cent. scab. The control of scab was unaffected by the ad- 

 dition of cane sugar to the lime-sulphur solution. {Hatch Fund) 



Poison Ivy Control 



Experiments in the control of poison ivy were made during the year 

 by 0. Butler, with sodium thiocyanate, using 10, 20, and 40 per cent, 

 solutions. Plants sprayed early in the season with the 10 per cent, solu- 

 tion sent out new growth before the end of the summer, but the plants 

 sprayed with the 20 and 40 per cent, solutions showed no signs of re- 

 covery. {State Fund) 



