1934 



ENCYCLOPEDIA OF PRACTICAL HORTICULTURE 



spots may run together. In severe cases 

 the leaves may gradually turn yellow, 

 wither and die. In certain instances the 

 disease has been reported as being so se- 

 vere that the plants are killed. 



Cause 



This disease is caused by a fungus 

 known technically as MycospJiaerella fro- 

 gariae. The mycelium grows in the tis- 

 sue, killing it and forming the character- 

 istic spots. This fungus is propagated 

 by means of summer and also by winter 

 spores. 



In the Northwest it seems to spread all 

 winter and it is possible that in this re- 

 gion the summer spores are sufSlcient to 

 keep the fungus perpetuated. 



Control HeasTires 



Only healthy plants should be set 

 Plants should be secured, if possible, from 

 fields where the disease was not present. 

 In any case all diseased leaves from 

 plants should be picked off before plant- 

 ing. Cutting and burning the foliage 

 after harvesting the fruit, as carried on 

 in some sections of Oregon, is an excel- 

 lent practice, since it destroys many 

 leaves affected with the disease. "When 

 the disease is severe, spraying may be 

 practiced. Use Bordeaux mixture 4-4-50. 

 In Oregon three sprayings are suggested 

 for trial, two in early spring before the 

 first fruits are half grown, and another 

 about the first or middle of September. 



Powdery Mildew of the Strawberry 



SpJiaerotJieca castagnei Lev. 

 The disease known as powdery mildew 

 is not common in this country, but in 

 one locality in Ontario, at least, it has 

 done considerable harm, and as it may 

 soon spread, it should be referred to here. 

 When this disease is bad, it covers the 

 fruit with mildew, making it unfit for 

 sale or consumption. The grower does 

 not usually notice the disease until it af- 

 fects the fruit, but as a rule it starts on 

 the under side of the leaves, which even- 

 tually curl up, and in order to control it, 

 it must be treated early, as the plants 

 cannot be sprayed satisfactorily when the 

 fruit is developing, although ammoniacal 

 copper carbonate might then be used. For 



spraying the foliage, Bordeaux mixture 

 may be used or flowers of sulphur in the 

 proportion of one part lime and two parts 

 flowers of sulphur. It is important that 

 the underside of the leaves should be well 

 covered, and even the soil, so that spores 

 may be destroyed. These are scattered 

 early in the spring from the tiny sacs in 

 which they are contained during the win- 

 ter. They soon germinate and attack the 

 leaves. As this disease spreads only on 

 the surface of the leaves, it is readily con- 

 trolled if treated at the proper time. 



W. T. Macoun, 



Central Experiment Farms Bulletin 62. 



STRAWBERBx PESTS 



Introduction 

 Strawberries and Insects 



X B. Smith 



In the course of this article the terms 

 "staminate" and "pistillate" are used in 

 referring to varieties, and it may be well 

 to explain the moaning of these terms and 

 their bearing on fruit production. 



The term "staminate" as applied to a 

 strawberry flower means that around the 

 central disc-like protuberance there is a 

 series of stems or thread-like processes, 

 the filaments, bearing an enlargement at 

 tip, the anther— -together called stamens. 

 On the anthers the pollen is produced, and 

 strawberry fiowers so provided are said 

 to be perfect or "staminate."' When these 

 stamens are absent, and only the yellow 

 disc-like center bordered by the white 

 petals is present, the flowers are said to 

 be imperfect or "pistillate." 



A bed of pistillate plants remote from 

 others or sheltered from insects could 

 never produce satisfactory, if any, fruit, 

 and pistillate varieties only are never 

 planted in one area. Staminate varieties 

 may be isolated in any way and will pro- 

 duce perfect fruits, provided the pollen 

 is brought into contact with the pistils. 



Where a mixture of varieties is planted, 

 the pistillate varieties will usually bear 

 quite as freely as the others, because the 

 staminate varieties bear a great excess of 

 pollen and have sufficient not only for 

 their own needs, but for many others be- 

 sides, provided only that there is a car- 



