-10- 



There are tv/o spore stages of the fungus, the spring spores called ascospores 

 and summer spores termed conidia. It is well to know these terms. 



Ascospores are shot forcibly from the old leaves on the ground a short dis- 

 tance into the air enabling the air currents to carry them farther. 



At ttie peak of ascospore production, usually in the late pink, it is stated 



that in 45 hours 8,170,200,000 spores can be ejected from the old leaves on 



the ground in a 1600 square foot area. Keitt found an average of 2J9 ascospores 

 per cubic foot of air in a 4 hour rainy period. 



Mature ascospores are ejected 5 minutes after the leaves become wetted. The 

 spores change color in maturity thus making it easy to tell when they are ready 

 to be shot out. 



Ascospores are four times larger than the majority of the sulfur particles in 

 most sulfur sprays, 



A moderate amount of infection can take place on unprotected leaves between 

 63° F. and 75*^ F., when the young leaves are wet for 12 hours. It takes only 

 13 hours of v/etting \;ith temperatures betv;een 64° F. and 75° F. to get severe 

 infection. 



On terminals, leaves below the fourth loaf are resistant to the scab fungus. 

 If scab appears on such leaves they were inoculated when young. 



Although Daldv/ins are considered by many to be resistant to the scab fungus 

 they may have as much infection as liacs. The fungus can change in its capa- 

 bilities of attacking certain varieties. 



Careful cost and production records have shown net profits, due to spraying, 

 of 4^65 to v<'00 per acre. 



The above are little knovm facts of my own choosing; the well knovm fact, of 

 course, is that we still have plenty to learn about the disease and tlie fungus, 



— Thomas Sproston 



WORCESTER CONCERIT TfAI JTS AP PLE ITOOD 



A much better offer for apple wood than was reported in February Fruit 

 IJotes comes from a large manufacturer in Worcester. This concern needs sound 

 apple wood of these dimensions; 2" tliick, 6" wide or wider, and at least 

 1* long. One gro\jer who plans to deliver some of this material says it takes 

 about 1-^- cords to make 1,000 board feet. 



For further details contact 'J. D. l/eeks, 1/orcester County Extension Service, 

 Post Office Building, 1/orcester, Mass. 



