No. l6.] INSECTS OF CONNECTICUT. 25 



Insecticides are usually applied in the form of a spray, by 

 means of a pump. In large orchards power sprayers are in 

 vogue, but for smaller operations hand pumps are preferable. 

 Advice regarding the most desirable forms of spraying ap- 

 paratus may be obtained from any agricultural experiment 

 station. 



Other control methods consist in the use of poisoned bait, 

 traps, sticky bands, hopper-dozers, and barriers, but these are 

 for special use against certain kinds of insects. Crop rotation 

 and cultural methods are practiced to forestall injury by certain 

 species. Poisonous gases are also employed when they prove 

 effective and inexpensive, as in fumigating nursery stock and 

 greenhouses with hydrocyanic acid gas to kill the San Jose 

 scale, and in treating stored grain with carbon disulphide to kill 

 the insects infesting it. 



With certain other pests it is necessary to destroy their breed- 

 ing places in order to control them. This is done in case of 

 mosquitoes, certain kinds of which transmit yellow fever and 

 malaria to man through their bites. It has recently been dis- 

 covered that bubonic plague is transmitted to man through the 

 bites of certain kinds of fleas which naturally live upon rats. 

 The destruction of the rats is therefore the chief preventive 

 measure in regions where this disease is prevalent. 



How Insects are Beneficial. 



The greatest benefit which man derives from insects is through 

 the part which insects play in plant pollination. A large pro- 

 portion of plants, including some of the fruits and other culti- 

 vated crops, depend on insects to carry pollen from one plant to 

 another. Without these insects there could be no crop. Insects 

 aid man by destroying other insects and plants which are in- 

 jurious or undesirable. To some extent they are scavengers 

 and makers of soil, whereas to a large extent they serve as food 

 for birds and fishes, and to a limited extent as food for man. 

 Honey and beeswax are two important products of insects, and 

 honey is an important addition to man's food. Wax and lac are 

 used extensively in the arts, and silk is an extremely important 

 material used as clothing. A large proportion of the food of 

 poultry and song birds is composed of insects. 



