Insects Affeeting the Strawberry. 83 



vantage of our insect enemies, this is of course to be preferred as a general 

 rule to any method requiring special labor, apparatus, and material. 



The favorite method of strawberry culture in Illinois is that of growing 

 the plant in rows, between which the ground is regularly cultivated for three 

 years, after which the whole field is plowed up and reset with young plants. 

 Of course, where this method is followed, if proper care be taken to set the 

 ground again with plants free from noxious insects, few injurious species 

 can make much headway; and if to these precautions we add that of taking 

 measures to prevent the spread of insect enemies from an old field to a new 

 one, we should certainly have the matter jjretty well under control, as far as 

 those species are concerned which pass their whole lives during all their 

 stages in the strawberry field. 



As an example of the use of barriers to progress, we may refer to the prac- 

 tice of opening new fields at a distance from the old, in order to prevent the 

 passage of the crown-borer from one to the other — a practice to which I shall 

 again refer farther on, while topical applications may be illustrated by the 

 use of Paris green on the vines, or even the fire cure, as applied for the leaf- 

 roller. 



Little can be done for the direct destruction of insect enemies until the 

 fruit is picked, unless it be the hand picking of grubs and cutworms, where 

 they are very numerous, or the use of harmless insect poisons, like pyre- 

 thrum, for some of the minor larviie which may perhaps require attention. 

 In June, after the crop is harvested, some things may well be done. The 

 field may be mowed, covered lightly with straw if necessary, and fired when 

 dry, thus destroying the leaf-rollers, and probably the plant-lice also, and 

 perhaps the strawberry worms, and the eggs and larvje of the Angerona and 

 of the "smeared dagger." Some other insects would probably likewise be 

 exposed to extermination at the same time by these means. 



The summer months (June, July and August), are the proper ones for 

 the application of poisons, which will take effect at this time upon the straw- 

 berry worm, some, at least, of the leaf-rollers the Angerona (if it should hap- 

 pen to be in the field), and the beetle of the root-worm. Some other species, 

 less common and destructive, would probably also be reached if present. 



If, as is not unlikely in a badly infested field, such measures as the above 

 are found after all ineffective, and the strawberry farmer finds himself re- 

 duced to the last desperate expedient of destroying the plants and their en- 

 emies together, he should carefully study the calendar in order to determine 

 at what season the greatest number of the species actually infesting his fields 

 may be exterminated by that means. At whatever season the plowing is' 

 done, if the ground is planted to another crop the following year, the croAvn- 

 borer will be destroyed, since its feeble migratory power will not enable it 

 to save itself by retreat. Still, plowing soon after berry-picking would most 

 certainly affect the entire destruction of the brood, since at that time no 

 adults are living, and few if any larvie would be far enough advanced to trans- 

 form in the dead crowns. Plowing in spring (March or April) would prob- 



