SECTION VIII 

 Fungoid Diseases 



Notwithstanding the enormous amount of mischief done by insect pests 

 to the various crops grown in the open air and under glass, that caused 

 by fungoid diseases is if anything more considerable, and necessitates a 

 large outlay every year to keep the diseases in check. While one may 

 by clean cultivation and attention to natural laws keep insect pests largely 

 in check, the very best cultivators may be caught napping when a fungoid 

 disease begins to ravage his crops. Slugs, snails, caterpillars, moths, butter- 

 flies, beetles, &c., after all are enemies that can be detected by an observant 

 cultivator, and measures for their suppression can be taken in good time. 

 Not so, however, with the various fungoid diseases that cause so much 

 mischief. In the early stages these are hidden from the eye, being of 

 microscopic proportions, and it is not until plants or fruits have been in 

 a measure destroyed that the disease is observable. The tiny speck or 

 blotch on a leaf or fruit to-day may develop into a large and putrid mass 

 of vegetable tissue to-morrow, filled with thousands of spores which will be 

 blown about by the wind, thus to carry disease and death to other plants. 



The true fungi consist of a large number of stemless cryptogamic plants, 

 the chief feature of which is that, unlike the higher Cryptogams (such as 

 Ferns), and the flowering plants proper or Phanerogams, they lack green 

 colouring matter or chlorophyll. Owing to this absence of green colour- 

 ing matter in the tissues, fungi are unable to utilize sunlight as a source 

 of energy and food assimilation. They cannot take in carbonic acid gas 

 from the atmosphere, nor can they absorb nitrogen. Indeed fungi give 

 off carbonic acid gas as a waste product. They must therefore obtain their 

 nourishment in a form already prepared for their reception either by 

 living plants or by dead ones. Hence there are two distinct groups of 

 fungi: (1) those that exist on or derive their food from dead plants or 

 organic material are known as "saprophytes", and (2) those that obtain 

 their food from living plants are called " parasites". As a rule the parasitic 

 fungi are most dangerous to the cultivator, because they attack his living 

 plants in various stages, and unless checked or eradicated are likely to 

 inflict serious losses. Intermediate between the true parasitic fungi and 

 the true saprophytic ones comes a class that first of all causes portions of 

 living plants to die by secretions or ferments of some kind, and then gains 

 an entrance into the living tissues, and eventually causes their death. 



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