THE COTTOJS^ STALK-BORER. 65 



As has been stated by Doctor Howard, it is the larva of the borer 

 that works in the cotton stalls. It confines its attack to the pith of the 

 plant. The amount of injur}" depends upon the size of the plant and 

 the number of borers. The writer found one plant about 3 feet high 

 at Yoakum which contained eight larvae, and which showed four 

 emergence holes. The twelve borers had eaten out all the pith from 

 the smallest branches to 3 inches below the surface of the ground in 

 the tap-root. The small twigs were only thin shells and crumpled like 

 paper between the fingers. 



Nearl}" all infested plants showed unmistakable evidence of previous 

 injury, yet the comparatively fresh and healthy condition of a few 

 stalks points to the probability of an occasional attack upon perfectl}" 

 healthy stalks. In the field showing an infestation of 20 to 25 per 

 cent of its stalks it was estimated that the injured stalks had borne 

 at least 80 per cent as much cotton to a stalk as had the uninjured 

 ones. If it is true that the borer attacks only such stalks as are dis- 

 eased or otherwise injured, then only a little damage can be attributed 

 to it; 3^et the borer's attack, added to the injury due to disease, must 

 hasten the death of the plant and thereby lessen the number of bolls 

 to mature. -v 



NATURAL ENEMIES. 



From material collected at Yoakum, Tex., on October 28 two para- 

 sites of Ataxia crypta i^erehved.. One, Ileterospilus ^vebsteri As\iui.^ 

 had entirely covered the pupa of A. crypta with its cocoons. In the 

 majority of cases, however, this parasite had spun its cocoon after 

 crawling away from the body of its host. Several masses of these 

 cocoons were found with no trace of either the larva or pupa of A. 

 crypta, visible, and in one instance the larvae of this parasite were 

 found in a hollow cotton stalk and no form of A. crypta near. The 

 second parasite belongs to the genus Etroxj^s and is a new species. 

 There is some doubt that this species is a parasite upon Ataxia, but 

 since it is parasitic upon beetles and its pupae were found in a stalk 

 bored out by A. crypta^ it is here placed on record as a parasite of the 

 latter. 



REMEDY. 



If at any time the injury by the insect should become serious the 

 numbers of the borer can be easily reduced by destroying the infested 

 stalks early in the fall. The time of destruction must, of course, vary 

 in different localities, but it should be as earh^ in October as possible 

 for the latitude of Yoakum. By October 28 not more than 10 per 

 cent of the borers had emerged. If the stalks had been destroyed 

 earl}^ in October very few borers would have escaped. To obtain the 

 best results, stalks should not be cut but plowed out, for many of the 



I. 



