The Bulletin. 33 



remedies. 



The culture methods of rotation, cultivation, etc., which are so 

 useful against a number of our cotton pests, are relatively useless 

 and impracticable against this. Furthermore, the Cotton Worm is so 

 seldom a pest with us that it would not always pay to adopt any 

 regular methods of prevention unless such methods were of themselves 

 the best for the cotton crop. 



On the whole, the methods of combating the Cotton Worm consist 

 in the application of direct remedies, in the form of poisons put on the 

 foliage to kill the caterpillars. They are so ravenous that they are 

 easily killed by this means, the main question being to devise means 

 for applying the remedies over large fields at low enough cost to be 

 profitable. The course usually adopted is to dust dry Paris Green on 

 the plants by the methods described in discussing remedies for the 

 Boll-worm on page 38 of this Bulletin. From 1 to 3 pounds of 

 Paris Green will be sufficient for treating an acre of cotton. It should 

 be dusted on as soon as the destructive work of the Cotton Worm be- 

 comes evident, without waiting until the tender top foliage is prac- 

 tically all eaten away. 



The Paris Green may be dusted on pure, or mixed with an equal 

 quantity of dry powdered air-slaked lime, or land plaster. If only 

 a limited area is to be treated the material can be dusted on by hand, 

 or it may be scattered broadcast when there is a good breeze blowing 

 so that it shall be widely scattered. While the application must be 

 thorough enough to get a small quantity of the poison on the growing 

 part of every plant, yet at the same time we must choose such methods 

 as are rapid and economical. It is best to do the dusting work in 

 early morning or late afternoon and evening, so that the dews will 

 cause it to adhere to the foliage. 



For further discussion of the dusting method of applying poison 

 to cotton the reader should see what is said on this subject in dis- 

 cussing the methods of applying poison for the Boll-worm on page . 



THE COTTON BOLL-WORM. (Heliothis obsoleta.) 

 Order Lepldoptera. Family Noctuidce. 



Description. — A greenish, grayish, or pinkish colored caterpillar 

 or worm, when full grown from an inch to an inch and a half in 

 length, which injures cotton by eating into the squares and bolls. 

 Found on cotton from the time the squares are formed, but attracts at- 

 tention principally in September and early October, at which time 

 injury to the bolls is sometimes serious. The same insect attacks the 

 ears of corn, when it is known as the Corn Ear-worm ; it also attacks 

 the green or ripening fruit of tomatoes, when it is called the Tomato 

 Fruit-worm, and it is sometimes also called the Tobacco Bud-worm 



3 



