JIail 2, 1908.] Agr') cultural Gazette of N.S.W. 409 



however, and when faxoui-a-Ulc conditions again ;irisf% sucli as moist and 

 still weather, it resumes spore-production, and the spots again become 

 black. 



It very often happens, however, that unfavourable conditions for late spore- 

 production arise, and when the diseased apples are picked, the grower sees 

 nothing upon them but light-brown dried-up scabs, which do not resemble the 

 familiar Black-spot, and are mistaken by him for the work of an insect, or the 

 roughness attributed to spraying by Bordeaux mixture. But when thes« 

 apples ai-e placed in the case with others, the still and moist atmosphere they 

 meet witli provides the very comJitions requii^-d for the resuini)tion of spore- 

 production. Conidiophores and spores are again produced, and the spots 

 1) come black, and the disgusted apple-grower comes to the conclusion that 

 the "spot" ha5 appeared since the apples were picked. Fungi, it may be 

 remarked, are able to develop independently of light, so that they are not 

 alf'-cted in the least by being shut up in the dark. The spores produced in 

 this manner are often curiously distorted, and the majority of them germinate 

 on the surface of the spot or on the skin of the apple, and peiish. Those that 

 do not germinate at once appear to be sterile, as the writer could not induce 

 an/ of them to put forth germ-tul)"s. Where the conditions are favourable 

 for late spore-production wliile the apple is still on the tree, no further 

 de^'elopment takes place after the apple is picked. The late crop of spores is 

 p oduced in the normal manner, and the fungus quietly retires from busine-s 

 to wait the time when the rotting of the fruit (if it is allowed to rot) enables 

 it to assume its saprophytic or winter form. 



The fungus, in its fusicladium form, seems to have a definite course to run, 

 and a definite amount of energy to work otf, and if it cannot do it naturally 

 in the orchard it will do it after the fruit is picked. Last year nearly every 

 apple-grower in Tasmania was complaining that the spot had appeared on 

 apples after they were picked, especially in the case of Scarlet Nonpareils, 

 and the writer was amongst those that suffered. Case after case, in which 

 the apples had been, to all appearances, quite free from clis^^ase when picked, 

 were found quite valueless after a few weeks in the apple store. Many of 

 the apples were covered Avith large black patches, where none had been seen 

 before Investigation showed, however, that in every case the disease had 

 already existed on the apple before it went into the store, and that it had 

 simply enlarged and developed there. Every spot showed a centre of dead 

 apple-cells, sometimes not as large as a pin's head, and sometimes .so small as 

 to be invisible without microscopic aid, from which the disf^ase had extended. 

 These dead and hard cells ("cork -cells," as they are sometimes loosely termed) 

 show that the parasite must have commenced opeiations while the host w.'is 

 capable of exercising its vital functions, as cells of this nature are produced 

 by the fruit as a defence against invaders. A ripe apple has, to all intents 

 and purposes, ceased its life, and if attacked by a parasite vvould simply rot 

 without any attempt at resistance. It is clear, therefore, that the disease 

 must have attacked the apples while physiological operations were in full 

 force, and then received a check, which preventeil its development until the 



