10 BULLETIN 78, U. S. DEPARTMENT OF AGRICULTURE. 



INJURY TO TOBACCO. 



The tobacco is attacked soon after planting, and feeding by the 

 larvae continues until the first or second week of July. The larvae 

 usually commence operations just below the surface of the ground, 

 although newly set plants are frequently attacked at the "bud" or 

 whorl of terminal leaves. As feeding continues the larvae, especially 

 the smaller ones, frequently enter the stalk and tunnel upward, the 

 burrows often extending to the base of the first leaves and some dis- 

 tance above the surface of the ground. (See PI. I, fig. a.) When not 

 feeding the "worms" are found about the base of the plant, usually 

 in cylindrical, web-lined galleries, which extend from the plant, often 

 for several inches, beneath the surface of the soil. 



Injured plants may usually be detected by their stunted or wilted 

 appearance, which is more noticeable during hot, dry weather. The 

 stems are in some cases entirely cut off, although this form of injury 

 is rather unusual. 



Although plants often partially recover they do not obtain full 

 growth, and it is evident that the presence of many dwarfed or 

 stunted plants must result in very materially lessening the yield. The 

 value of the crop is greatly decreased also, owing to the large proportion 

 of late plants resulting from replanting. Early planted tobacco is 

 usually better in quality than the late planted, it being finer and 

 more elastic, curing better, and consequently bringing higher prices. 

 The attacks of the larvae often make it necessary to reset the crop 

 several times, and a good stand of plants is not secured, if at all, until 

 too late to make the crop as profitable as it should be. 



INJURY TO CORN. 



Owing to its wide distribution in the Eastern States the tobacco 

 Crambus is a serious pest to the corn crop. Injury has been noted 

 in many localities where little tobacco is grown, and it is probable 

 that damage to corn amounts to even more than that to tobacco. 

 As with tobacco, injury is most severe when corn is planted on land 

 which has been in weedy pasture or meadow previously, or when 

 planted on land which has not been under cultivation for a number 

 of years and on which there has been a rank growth of weeds. On 

 such land it is usually difficult to secure a satisfactory stand of corn, 

 and the yield is greatly reduced. (See PI. I, fig. b.) In central 

 Virginia many fields under observation were replanted several times, 

 and owing to the lateness of the season when a stand was secured 

 the value of the crop was decreased fully one- third. Corn or tobacco 

 planted on newly-clearea land seldom suffers injury from the Crambus. 

 Since the species of weeds which are the natural food plants of the 

 insert do not thrive in woodland, the larvae are not present when the 

 crop is planted. 



