-8- 



6. Timing of successive applications must be right to obtain greatest effect; 

 proper timing varies with materials and weather, 



Ellsworth H, Iheeler 



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POYJDERY IflLDM FOUND IH MASSACHUSETTS 



Povjdery mildew was found on termnal leaves and twigs of bearing apple trees 

 in 'Worcester County by Bill Goss on August 26» Me have been expecting it because 

 ether states near us, where organic fungicides have been used extensively for 

 scab control, have had increasing amounts of it for several years, This is a 

 serious disease and under the right conditions can cause heavy losses. Now it 

 is here. 



The pcfwdery mildew fungus ( Podosphaeria leucotricha) attacks the young 

 tender leaves, tvfigs, blossoms, and fruit of apple. It grows mostly on the 

 surface but it also penetrates into the soft tender tissues of the twigs and 

 bud scales where it winters over to cause spr^-ng infections* The pov;dery 

 spores are produced in abundance on the affected tissues and require very little 

 moisture - light rains and even dew are sufficient - for germination. 



The disease is usually more serious when it starts in the spring and there 

 are frequent rains but it may start at anytime when tissues are soft and there 

 is a little moisture. 



What To Do I 



1, Examine the orchard regularly for mildew - it starts as patches in a 

 tree - and take care of them right away, 



2, Prune out the infected terminals. The fungus will die in a few hours 

 after the termj.nal is cut off. 



In vdnter pruning, cut out all tenninals which have a gray or silvery 

 appearance. Pruning out is important because it reduces hold-over infections 

 from which mildev/ starts in the spring, 



3, In the spring, spray thoroughly with sulfur in pre-pink and pink, at 

 which time mildew begins showing up, spacing sprays a v;eek apart. Better kill 

 will be obtained when temperatures are about 8^° or low 90 's, in which case it 

 may be advisable to use 2 pounds of 325 mesh sulfur rather than the finer 

 sulfurs. Growers who are on a sulfur scab control program, either alone or 



in combination, will not need to switch to sulfur during this period for 

 powdery mildew control, 



C, J, Gilgut 



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