LBCT. v ENEMIES OF CROPS AND TREES 



79 



golden rule to follow. Absolute prevention of insect 

 and fungoid attacks may not be possible, but it is 



FIG. 18. POTATO DISEASE FUNGUS (PHYTOPHTHORA). 



A to B, tranverse section of potato leaf showing mycelium (spawn) of 

 fungus. C, fungus growing through leaf. D, "fruiting." E, breathing 

 pore in leaf F, conidia (spore cells) dividing. G, a cell enlarged 

 400 diameters, showing tailed zoospores emerging for spreading the 

 disease. The figure on the left is taken from Griffiths' Diseases of Crops 

 (Bell), those on the right (by W. G. Smith) from the Journal of Horti- 

 culture. 



possible and practicable to prevent the enemy ga- 

 thering in countless thousands and becoming a 

 devastating horde. "Waiting for plant enemies to 

 multiply before resorting to repressive measures is a 

 waste of time and material, plants and crops suffering 

 in the meanwhile through the procrastination. 



