230 JOURNAL OF ECONOMIC ENTOMOLOGY [Vol. 12 



staminate flowers. Were this feeding habit more frequent, a serious 

 loss of pollen might result. A plat of two acres of field corn in which 

 tassels were appearing July 3, 1918, was examined carefully and only 

 ten tassels found to be thus injured. Since corn produces an excess of 

 pollen, the loss of a few anthers is not serious. 



By far the more important losses due to ear worm activity come from 

 the attacks on the ears. It is well known that ear worm moths ovi- 

 posit in the majority of cases on the fresh silks. The larvae, upon 

 hatching and after devouring the empty egg shells, begin at once to 

 feed on the fresh silks. Sometimes the larvae crawl down the silk 

 strands well into the tip of the ear at once but not infrequently they 

 feed more or less exposed on the silk at the tip for several instars (cf . 

 Headlee, 1913).^ Perhaps the most frequent type of silk injury is 

 where the larva severs the strands some distance below the ends of 

 the husks (PI. 11, fig. 3). This condition is so frequent that a slight pull 

 of the silk mass will generally indicate infested ears. If a part or all of 

 the silk pulls out readily, ear worm work with but a few exceptions is 

 assured. Where the silk does not yield, the husk must be opened to 

 ascertain infestation. 



Since it is through the silks or styles that the ovules are fertilized 

 resulting in the development of the kernel, severance of the silk before 

 fertilization will result in the absence of kernels on that part of the ear. 

 It has been observed that the silks leading to the basal portion of the 

 ear develop first and those to the tip, last. Dr. W. A. Taylor of the 

 Bureau of Plant Industry, when asked for confirmation of this state- 

 ment wrote {in littera), "the silks usually arise from a point an inch 

 a two from the base of the ear. From this point the silking proceeds 

 toward the tip and less rapidly towards the base. The last silks to 

 emerge are from the tip of the ear." It appears that fertilization takes 

 place over the greater part of the ear before ear worms reach the silks 

 but some four or five days are necessary to fully pollinate a single ear 

 of corn (Coulter, 1913) .^ Within this time ear worms enter the silk 

 mass, sever some and thereby prevent fertilization of the tip ovules in 

 which case a nubbin results (PL 11, fig. 8). Occasionally some kernels 

 missing at the base of the ear may be explained in the same way but 

 this is less common apparently than poorly filled out tips. The silks to 

 the tip ovules are, in general, in the center of the silk mass. The larvae 

 appear to enter the ear generally through the center of the silk mass, 

 eating as they go. If the larva merely eats in the external silk mass^ 



1 Headlee, T. J. Rept. of the Entomologist. N. J. Station Rept., 1913, pp. 633- 

 789, pis. 4, fig. 3. 



2 Coulter, John M. Elementary Studies in Botany. D. Appleton and Co., N. Y. 

 453 pp., 97 figs. (Corn, 343-351.) 1913. 



