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A New Enemy of the Black Locust. 



Glenn Culbertson. 



During the hitter part of June and during July of 1914, the leaves of 

 the greater number of the locust trees in Switzerland, Jefferson, Clark, 

 and Floyd counties, of southern Indiana, were observed to be losing their 

 greenish appearance, and upon closer examination the chlorophyll of the 

 leaflets was found to have been largely consumed. The foliage appeared 

 as though dried up as a result of a severe drouth. Here and there indi- 

 vidual trees, at a distance from groves, were unaffected, but the trees of 

 practically every grove, at least among the hills of the Ohio and tributaries 

 were seriously affected. So evident was this that the brown and sere 

 appearance of the groves was noticeable as far as they could be seen. 



The infected trees were found to be alive with a small beetle, which 

 Professor Enders of Purdue classified as Chalepus dorsalis of Blatchley*s 

 "Coleoptera of Indiana'" : 'This beetle is from 6 to 6.5 mm. long, wedge 

 shaped and rather broad, bluish black, thorax red. with black sutural 

 stripe. Found throughout the State, but much more abundant in the south- 

 ern counties. Occurs on flowers of black locust, in the leaves of which the 

 larvse mine. Hibernates beneath the locust bark." 



On striking the trees the beetles could be heard falling to the ground 

 by the scores. They could be seen in large numbers on the foliage, as 

 many as five were counted on a single leaflet. 



The eggs of this beetle are deposited late in April or early in May, and 

 by the 20th of May the young larvae are at work between the coverings of 

 the leaflets, destroying all the inside portion. In some cases several larvae 

 may be seen at work within a leaflet. When mature the larvae stop eating 

 and remain enclosed within the leaf coverings until metamorphosis is com- 

 pleted, when they emerge, usually about the 20th or 2.1th of June, and for 

 several days feed upon the upper leaf surface of any green foliage that 

 may remain. 



The writer is of the opinion thai many of the locust groves in the 

 northeastern part of Jefferson County were badly infected with this beetle 



