176 STATE HORTICULTURAL SOCIETY 



It appears early iu the growing season, causing olive-brown spots on 

 the leaves, which are sometimes liearlv destroved bv the attacks. On the 

 fruit the dark spots, when young, are rounded more or less, and the 

 margins are white, caused by the uprising of the epidermis. An illustra- 

 tion through a spot on the apple is here shown much enlarged. The scab 

 is only skin deep, so to speak, but as it progresses some of the outer cells 

 of the fruit are destroyed. As it spreads the center of the spot becomes 

 thicker and often cracks ojien, j^ermitting other fungi to get a foot-hold 

 and cause decay. 



Here iu the section are shown some brown stems bearing spores at the 

 top, and the spores are represented below^ as germinating, some tw^o- 

 <3elled, but mostly one-celled. Eipe spores will grow in dew or water in 

 a few hours and will pierce the cuticle of the fruit and start a spot of 

 the scab. 



These spores may live over winter on fallen leaA'es or fruit, and some 

 of them, at least, I have found on the young stems and bud scales at 

 any time from summer to the next spring. These are ready for a renewal 

 of business on the approaching young leaves and young apples, even 

 before blossoming. 



The scab is not the immediate cause of rot in apples. When started 

 early it causes the apple to cease growing in the region of the spots, or 

 at least to grow slower than the parts unaffected. A fungus that feeds 

 on a living host is known as a parasite. For treatment, I refer to bulle- 

 tins from the horticultural dejtartment, and this suggestion refers to 

 most of the other fungi spoken of. 



In the laboratory, we prepare pieces of the apple or leaf by hardening 

 in strong alcohol, embedding in collodion, and then cutting thin sections 

 with a delicate machine called a microtome. A few fresh spores are 

 taken from a spot, placed in a small, flat drop of water on a thin piece of 

 glass, and then turned over and placed on a glass cemented tight with 

 asphalt and vaseline. Here we have a hanging drop over an air-tight, 

 moist chamber. From time to time the prejiaration may be placed under 

 the microscope so the student can see how things are progressing. Fresh 

 young fruit is inoculated and kept under a bell-jar, where the SA'uiptoms 

 can be observed. It is nice, interesting work for the inquiring student, 

 who has a good stock of mechanical sidll, not omitting to mention pa- 

 tience and perseverence. 



8oft-rot, blue mould {PcnicilUuin glai(cnm Link.), feeds on a great vari- 

 ety of substances, among them mature apples, not on the green leaves or 

 growing fruit. Such a fungus is known as a saprophyte and not a para- 

 site. Where is the fruitgrower of any experience who has not carried 

 from his warm cellar in winter or spring bushels and barrels of soft 

 apples, all in the' form of a worthless mush? Here soft-rot had got in 

 its work. It is a low" form of plant, whose minute spores are almost 

 omnipresent. These spores, when growing, apparently can not penetrate 

 the skin of a sound apple, but are ready to drop into any w^orm-hole or 

 crack or defect caused by a break in the skin originating from a bruise 

 or a punch of a straw' of the stubble. In ripe fruit this fungus runs its 

 course in a hurry. After the white thieads run through and through, 

 feeding on the apple, the fungus, true to its nature, ])ushes out large 

 numbers of minute, delicate threads, which branch at the tip, and these 

 ^branches finally become spores, and when seen in mass have a bluish- 



