412 ECONOMIC ZOOLOGY AND ENTOMOLOGY 



orchard or field. It is usually much easier and cheaper to 

 prevent an insect from getting a start in the orchard or garden 

 than it is to fight it after it has gained a firm foothold. "An 

 ounce of prevention is worth a pound of cure." 



Among the most effective means of preventing insect injury 

 may be mentioned the following: 



High Cultivation. This not only makes the tree or other 

 plant yield its best returns but it is a well known fact that a 

 strong healthy plant is not nearly as apt to be attacked by as 

 many insect pests as one that is already weakened or, if it is 

 attacked, it is able to stand much more injury without the 

 effect being shown in the crop it yields. The first and best 

 way of fighting insect pests is then to keep the plant in the 

 very best condition possible by high cultivation, judicious 

 pruning, fertilizing, etc. 



Clean Culture. Many of the most injurious insects pass the 

 winter months under rubbish of various kinds that lies scattered 

 over the farm. If this rubbish is not allowed to accumulate 

 such insects will be more likely to perish during the winter. 

 Keeping clean will also reduce the opportunities for feeding and 

 breeding and allow a more thorough application of insecticides. 

 In orchards this recommendation for clean culture is of especial 

 importance. Many insects breed and complete their develop- 

 ment in dead wood or fallen fruit, others pass the winter months 

 or lay their winter eggs upon the smaller branches of the trees. 

 If the orchardist would take the pains to trim out and burn all 

 the dead and infected branches, and to see that all fallen fruit 

 was destroyed, there would be little complaint of some of the 

 insects that are now serious pests. 



Crop Rotation. Many insects live only on one kind of plant, 

 and when not able to find this plant they perish or are scattered 

 so as to do little damage. This fact may often- be taken 

 advantage of by a system of crop rotation. 



Protection of Plants. Many small plants, especially in the 

 garden, may be protected by screens or other devices for 

 keeping the pests away from the plants. 



Late Plowing. Many insects may be killed or exposed to 

 their enemies by plowing the field late in the fall. Some of 



