44 
deeper into the soil nor causes them to migrate to any appreciable dis- 
tance; that kainit used as a fertilizer, even in very large quantities, had 
little if any effect on the wireworms;* that muriate of potash—four to 
six tons to the acre (an excessive amount)—is but shghtly effective; 
that lime at the rate of even two hundred bushels per acre does not in- 
jure wireworms; that chloride of lime must be used in impracticable 
quantity to produce any marked effect; and that gas-lime, although capa- 
ble of destroying the wireworms, must be applied in such great quanti- 
ties that its use is impracticable on large areas. Bisulphide of carbon 
poured into a hole in the earth near the infested hill destroys the wire- 
worms, but at an excessive cost. 
The most promising remedy for wireworms, in my judgment, is 
one which has unfortunately not been experimentally tested, but which 
is, nevertheless, precisely based upon our knowledge of the life history, 
food, and habits of these insects. It consists of a rotation in which 
clover follows always upon grass and is itself followed by corn. Ac- 
cording to this plan pastures “and meadows of grass might he unchanged 
for several years, being plowed, when broken up, in late summer or 
early fall and sown to clover in the spring—either with oats, or on win- 
ter wheat or rye sown the fall before. The clover should be allowed to 
stand a second year, and might then be followed with corn with positive — 
assurance that the wireworms originally in the sod would by that time 
have entirely disappeared. From the regular rotation for grain lands, 
grass would thus be excluded. In such a rotation corn might be fol- 
lowed by small grain, this by clover, and this by corn. While the wire- 
worms might produce some visible effect on the small grain the first 
year after ; grass, this would usually be much less serious, at any rate, 
than the damage to corn. 
The general entomological effect of some such management could 
not fail to be beneficial, since it would apply to cutworms and white 
grubs as well as to the wireworms now under discussion. The system of 
rotation now common in Central Illinois is, indeed, seriously defective in 
the fact that the plants composing it—Indian corn, small grains, and 
erasses—are all of the same botanical family and consequently subject 
in large measure to the same enemies. Any variation of this system 
which will introduce as a regular link in the chain a crop belonging te 
some other and widely different family of plants, will serve the general 
purpose of that here proposed. 
“) . * These results are inconsistent with those reported by Prof. J. B. Smith in the 
12th Ann. Rep. N. J. Agr. Exper. Station (for the year 1891), p. 412. Here Professor 
Voorhees, Chemist of the Station, is said to have ‘applied kainit and muriate of 
potash separately to two sections of a fourteen-acre piece of corn on ground always 
badly infested by wireworms and cutworms, leaving a strip between these sections 
without treatment. Care was taken that the sections should be similar with respect 
to quality of land, situation, ete. As a consequence, the kainit section was reported 
as almost entirely exempt from injury by insects, the muriate section as but little 
infested, and the intermediate strip as almost destroyed. It is evident from the 
context that this experiment had been made some years before, apparently not under 
the inspection of an entomologist. 
