SMITHSONIAN INSTITUTION LIBRARIES 



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The newly-hatched insect is pale green marked with black, but with successive 

 molts takes on certain orange markings. The eggs hatch on the third or fourth 

 day after laying, and the young bugs go through all their molts and arc ready for 

 reproduction in about two weeks. There are many generations in the course of 

 the summer ; in the South probably as many as seven or eight, while in Maryland 

 there may net be more than three or four. ( >n the advent of winter the adult in- 

 sects crawl away under any kind of rubbish to hibernate, reappearing in the 

 spring with the first warm weather and flying to the first cruciferous plants 

 which come up from the ground. The earliest specimens congregate upon mus- 

 tard and early radishes, flying later to cabbages. The eggs are laid as soon as the 

 firs! food plants have grown up to any extent ami put out their leaves. In 

 Mississippi this takes place the latter part of March, and each female will con- 

 tinue eggday in g for about ten days. In the District of Columbia the eggs are 

 ordinarily not laid until nearly a month later, although the date depends entirely 

 upon the character of the season. The insects hibernate, as a general thing, near 

 old cabbage fields, and the first eggs are laid upon mustard or other wild crucifer- 

 ous plants which may be growing in the neighborhood of the fields. Where 

 early cabbages are set out, the first eggs are sometimes not laid until the cabbages 

 are in place. 



REMEDIES. 



The insect is a very difficult one to kill, and none of the early recommendations 

 which looked to the destruction of the species while at work upon cabbage were 

 satisfactory. Even kerosene emulsion, which ordinarily is so fatal to sucking in- 

 sects, must he applied so strong, in order to kill this ling, that it will ruin the 

 cabbages. Destruction of the over-wintering individuals is the important point 

 to be striven for. They cluster largely upon mustard and radishes in the early 

 spring, and as there is ordinarily nothing to be gained by saving mustard, in 

 particular, pure kerosene, or kerosene emulsion diluted with only one part of 

 water, should be applied. The planting of a little trap crop of mustard is an ad- 

 mirable idea which has been suggested by Mr. II. E. Weed, of the Mississippi 

 Agricultural Experiment Station, and this remedy has been tried with excellent 

 effect in Mississippi. On one occasion he planted a row of radishes through the 

 middle of a crop of cabbages which was put into the field early in March. The 

 radishes were well grown by the time the second brood of bugs were hatched, and 

 nearly all the insects found their way to the radishes and were there 1 killed by 

 spraying with kerosene applied by a hand force pump or common watering pump. 

 In small fields where the first noticed bugs occur upon kale or broccoli, it will 

 pay to send a boy through with a hand-net and have him sweep the bugs from 

 the crop into the net, when they can be destroyed. Many can be captured in this 

 way, and the numbers of the later broods greatly reduced. 



NATURAL ENEMIES. 



The harlequin cabbage bug is singularly free from theattacksof natural enemies 

 Birds and poultry seem to leave it alone. Prof. II. A. Morgan, of Louisiana, 

 however, has discovered that the eggs are pierced by a minute parasite, sometimes 

 so extensively that in September, 1892, out of over one thousand eggs, nearly all 

 were killed. This parasite is Trissolcus murgantise Ashm., a species which has 

 hitherto been known only from Louisiana, but which it. may pay to bring to Mary- 

 land, if the harlequin cabbage bug is allowed to increase. 



Approved : L. O. Howard, 



('mas. \Y. Dabney, Jr., Entomologist. 



Assistant Secretary. 



Washington, I>. C, May 24, 1S05. 



