SMALL WORMS BORING IN THE ROOTS 111 
ing the overwintering queens, migrate to it. The whole thing is then 
covered with canvas and fumigated with carbon bisulphide. Summer 
colonies are killed by fumigation in the same manner as described above 
for other species, or by poisoning with dilute arsenic and sweetened 
water, as described in the chapter on Household Insects. 
The Southern Corn Root-worm (Diabrotica duodecimpunctata Oliv.) 
The presence of the southern corn root-worm or ‘ bud-worm”’ is 
usually first indicated by an enfeebled growth of the young plants. 
The leaves turn yellow, or the plant simply fails to make a normal, 
vigorous growth. Ifa plant is pulled up and the roots are shaken, some 
of the grubs will likely be thrown out, and the round holes where they 
have bored into the side of the main stalk, just below the ground, will 
be noted. The grubs are about three fourths of an inch long when full 
grown, are quite slender, smooth, white or light yellow, and have a 
small brown head. 
The adult of this worm is a small beetle, about one fourth of an 
inch long, commonly known as the twelve-spotted cucumber beetle. 
It is greenish yellow in color, and has twelve black spots on its back. 
It feeds on the pollen or silk of corn, on a great variety of garden 
crops, especially cucumbers, squashes, melons, and related plants, and 
sometimes on the young heads of various grains or grasses. 
Control of the root-worm in corn is largely dependent on general 
farming methods. Crop rotation will help to hold it in check, and so 
will systematic clean tillage. The worms do not infest the roots of 
cotton, buckwheat, or the smaller grains. Late-planted corn is less 
liable to attack, and so is corn in well-drained land. Many farmers 
find it expedient to plant an excess of seed. Remedies for the adults 
on garden crops are given elsewhere. 
The Western Corn Root-worm (Diabrotica longicornis Say) 
In the Central states the roots of corn are injured by a small, slender 
worm which mines in the main roots, tunneling here and there, seriously 
checking the growth of the plant if not killing it entirely. The worm is 
