246 INSECTS AFFECTING VEGETATION 



of potassium across the well-defined path by which the ants leave 

 their nest ; this kills very many, and deters the ants from taking the 

 direction of the particular path thus obstructed. 



Puncturing of the terminal portion of the stalk by plant bugs 

 occasionally occurs, but is comparatively rare. There is but one 

 borer in the stalks of cotton, and that is the long-horned beetle. It 

 is occasionally mistaken for an enemy to the plant, but investigation 

 has shown that it lays its eggs upon and its larvae bore into only 

 such stalks as have been damaged by some other cause, such as rust. 

 It follows injury to the plant, therefore, rather than causes it. 



As in the case of the stalk borer just mentioned, numerous 

 species of insects are found in damaged bolls which are the result, 

 rather than the cause, of the damage. Several little Nitidulid beetles 

 are found in such injured bolls. The larva of a little weevil deserves 

 especial mention for the reason that it so closely resembles the larva 

 of the Mexican cotton-boll weevil. In fact, the Iarva3 of both species 

 are found living in the same boll. The perfect weevil is also among 

 the various insects which are mistaken by the planters for the Mexi- 

 can cotton-boll weevil, but its very short and blunt beak should at 

 once distinguish it from the latter species. Aside from the true 

 boll-worm, several of the caterpillars found upon the plant will 

 occasionally gnaw the bolls, but this gnawing is in general inci- 

 dental to their work upon the leaves. One of these is a leaf roller 

 which attacks the forms and squares, much like the young boll- 

 worm, afterwards feeding upon the leaves. A congeneric species 

 also bores into the young bolls. The reddish larva of a little Tineid 

 moth belonging to a group mostly composed of leaf miners, is often 

 found in the young bolls, and is generally believed by planters to 

 act independently of bollworm damage. This statement, however, 

 has not yet been satisfactorily substantiated so far as it refers to the 

 bolls. In the young squares, however, the active little reddish 

 larva is very often found as unquestionably an original inhabitant, 

 and it undoubtedly frequently causes quite an extensive shedding of 

 the squares. This, however, occurs only in the spring, at a time 

 when there is surplus of bloom and when many squares can be 

 spared without great reduction of the crop. Later in the season the 

 larva is found boring in the unopened flower heads of various weeds. 



There is a class of damage to the bolls which is known to 

 planters as sharpshooter work, which is mainly caused by the punc- 

 tures of a leaf hopper. The insect is most abundant from the first 

 of June on through the season. Prior to the first of June it seems 

 to prefer the young growth and foliage of poplars and other trees 

 which may grow in the immediate vicinity. Where sharpshooter 

 work is prevalent in the cotton field, year after year, and the trees 

 which harbor the insects can be found in the early part of the 

 season, a single application of kerosene emulsion to the lower parts 

 of such trees or scrub growth might be made to advantage in the 

 month of May. 



An insect which at one time did very considerable damage to 

 cotton bolls, particularly those which were far advanced or had burst, 



