84 



CONTROLLING INSECTS AND DISEASES 



Mechanical Means of Controlling Insects. — All the above are 

 very indirect, yet often quite efficient, means of avoiding trouble 

 from insects and diseases. Unfortunately they are applicable 

 only in the case of certain enemies, and other means of control 

 must be sought. Certain mechanical means, somewhat less in- 

 direct than those mentioned above, can be employed to prevent 

 injury to certain crops by their insect enemies. Protection of 

 individual plants of cabbage or tomato from cutworms may be 

 afforded by wrapping a piece of stiff paper about the stem of the 

 plant when it is transplanted (Fig. 45). Individual hills of melons 

 or cucumbers may be protected from striped beetles by means of 

 a bottomless box or frame covered with mosquito bar or cheese 

 cloth. Plants growing in hot- 

 beds or coldframes may be pro- 

 tected from this insect enemy 

 by covering the entire frame 

 with netting w^ith sufficiently 

 fine mesh to exclude the insects 

 in question. A similar method 

 may be employed to protect 

 young cabbage plants from the 

 maggot (Fig. 46). Another 

 mechanical means of control- 

 ling insects is hand picking of 

 the insects or their eggs. This 

 method is applicable to the 

 tomato worm and celery cater- 

 pillar, and on small areas to the squash bug and potato beetle. 



The use of trap crops, poisoned baits and repellants are also 

 indirect methods of controlling insects. A trap crop is planted 

 in advance of the regular crop with a view to having the insects 

 collect in large numbers on this crop, where they may be destroyed 

 before the plants of the regular crop appear above the ground. 

 Squashes are sometimes planted as a trap crop to aid in the pro- 

 tection of cucumbers or melons from the striped beetle. 



Poisoned baits may be used to kill off cutworms immediately 

 preceding the planting out of cabbage and tomatoes. The usual 

 method of preparing poisoned bait is to dip freshly cut clover into 

 a strong mixture of Paris green and water, or to make up a stiff 

 bran mash to which Paris green and sugar or molasses are added. 

 In either case, the bait is scattered around the area to be planted. 



Fig. 45. — Cabbage plant wrapped with stiff 

 paper as a protection against cutworms. 



