EXPERIMENT STATION BULLETINS. 



451 



was the effect of the strong hme-sulphur on pear-leaf bhster mites which 

 had become well established on the young leaves. The lime-sulphur killed 

 most of the leaves which had developed at the time of application and at the 

 same time effected a thorough clean-up of the mites. 



ORCHARD NUMBER 4. 



This orchard is also near Fennville and the trees under observation were 

 mostly Kieffer. One block of mature trees was sprayed with lime-sulphur, 

 63^-50, just after the blossom buds had separated but did not receive an after- 

 blossom application of nicotine sulphate. The control by this one application 

 was not satisfactory as nymphs of the second summer brood were present in 

 June in considerable numbers. A few isolated trees near this block which 

 were not sprayed at all for psylla control were seriously infested in June. 



Fig. 8. — A view in Orchard No. 3, showing condition of trees where the psylla had been controlled 

 by two thorough applications, one before blossoming to destroy the eggs and one after blossoming to 

 destroy the nymphs. Picture taken Oct. 8, 1921. 



