60 



THE PRACTICAL ENTOMOLOGIST. 



THE WHITE GRUB. 



BY BCN.I. I). 



The " White Grub," as it is popularly called, is 

 a soft, white, six-legjred larva, with a light maho- 

 gany colored horny head, and when full-grown is 

 nearly as large as a man's little finger. Like the 

 rest of -the entomological group to which it belongs, 

 it usually curls its body up iu a semicircle, so that 

 its head almost touches its tail, though it has the 

 power of straightening itself out, when laid on a 

 flat surface, and crawling very slowly along upon its 

 belly. It lives several years in the larva state, and 

 finally in the early spring changes into a dark 

 chestnut-colored beetle about an inch long, and 

 with long slender legs, which flies round in warm 

 evenings in May with a buzzing noise and is often 

 attracted into houses by the light. From the month 

 in which this beetle appears, it is popularly known 

 as the" May-bug" or more correctly speaking '' May- 

 beetle." Its scientific name is Lachnosterna qucr- 

 ciiia, and a figure of it will be found in Harris's 

 Injurious Insects p. 30. 



There is another very .similar larva, often found 

 very abundantly in dunghills and occasionally under 

 eow-dungs in the fields, which by inexperienced 

 persons is often confounded with the true "White 

 Grub." As this larva is necessarily carted out into 

 fields along with dung, I have known many men to 

 suppose that thoy had thereby introduced the 

 " White Grub" into their fields, and thus furnished 

 a rod for their own backs. This, hovrever, is an 

 entire mistake. The true "White Grub" feeds 

 exclusively upon living vegetable matter, and ge- 

 nerally upon the roots of living and growing plants. 

 The other larva, which is in some localities distin- 

 guished as the " muck-worm," feeds exclusively 

 upon dung ; and hence the black dung that it has 

 devoured shows through its white, semi-transparent 

 skin all the way from its head to its tail like a large, 

 lead-colored intestine. In the true " White Grub," 

 on the contrary, it is only near the tail that the con- 

 tents of the body exhibit a lead-colored appearance, 

 because it is only near the tail that the roots upon 

 which it feeds have become digested and converted 

 into a dark-colored excrement. The only damage 

 that the " muck -worm" can do is to consume a por- 

 tion of the manure, which would otherwise go to fer- 

 tilize the soil. We shall shortly see that the " White 

 Grub" operates in a most injurious manner upon a 

 great variety of the crops raised by the Agricultu- 

 rist. Singularly enough, not only do the larvae of 

 these two distinct species closely resemble one ano- 

 ther, but the perfect insects also have a general re- 

 semblance and are often confounded together, as 

 they appear at the same time of the year and fly in 

 the same manner in the dusk of the evening. The 

 beetle produced from the "muck-worm" (L!gi/rus 

 relictu^i) may, however, be distinguished hy the 

 general observer from the " Jl ay-bug" by its legs 

 being short and stout instead of long, slender and 

 sprawling; and in numerous scientific details the 

 two difler very widely. In the Prairie Farmer for 

 August 9, 18G0, (p. 82) I have giveu aa outline 



figure of each, and also of the common " White 

 Grub." 



In gardens, the "White Grub" is particularly 

 destructive to strawberry beds, and is probably one 

 of the chief reasons why this plant will not last 

 more than a few years on the same spot of ground 

 in this country. It is also, as I have noticed for 

 many years, very destructive to beds of head-lettuce, 

 devouring their roots under the surface of the 

 ground so that the plant withers away and dies, in 

 which respect the habits of this insect are nearly 

 the same as those of the common " cut-^orm." It 

 is not, however, near so easy of discovery as the 

 " cut-worm," as it usually lies mucli deeper in the 

 earth ; but if not found and killed, it will travel 

 along a whole row of plants, killing them all one 

 after another. In spading up garden ground in 

 the spring, it is a very common thing to meet with 

 this insect either in the larva or in the perfect state j 

 and care should be taken always to destroy all that 

 are thus met with. 



In tame grass meadows this larva has been known 

 for time immemorial both in the East and the West 

 as a most destructive pest, devouring the roots of 

 the grass so that large patches can be rolled up like 

 a carpet. It has also been long known in Illinois 

 to be very injurious to young trees in nurseries, 

 often entirely ruining large quantities of them. Mr. 

 Kinney, the nurseryman of Rock Island, Illinois, 

 informs me that last season it destroyed for him, on 

 a moderate computation, a thousand dollars' worth 

 of young trees. Yet, compared with many similar 

 establishments in this State, his nursery is of very 

 limited extent. 



Twenty years ago I detected numerous " White 

 Grubs," cutting off the young corn when it was only 

 a few inches high, in an eleven-acre field of prairie 

 land, which I had had broken the preceding year 

 and had recently planted in corn. Along with the 

 "White Grub" there were also many " cut-worms " 

 and "wire-worms" engaged in the same mischievous 

 operation ; and so numerous were those three in- 

 sects, that I was obliged to go over the field several 

 times, unearthing and destroying them, in order to 

 save my crop. But of late years, as will appear 

 from the following extracts, in certain parts of the 

 country, the "White Grub" has increased and mul- 

 tiplied 80 extensively, that it not only thins out the 

 young corn, when it is only a few inches high, but 

 destroys the full-grown corn over the whole surface 

 of entire fields. 



On Prairie Eonde [in Michigan], which was formerly 

 noted for its great corn crop, the " White Grub" (Mclo- 

 lontha) has appeared in such numbers for a few years 

 past, as to nearly destroy many fields of corn, and has 

 sometimes been very injurious to wheat. I visited this 

 locality in August, 1864, and was surprised to find farm- 

 ers whose corn crops were so nearly destroyed, that they 

 were selling their nogs in a lean state, because they had 

 not the means to fatten them. On examining the few 

 corn-stalks that remained standing, I found the roots ge- 

 nerally eaten off to within a few inches of the stalk, and 

 often from three to five large grubs in a hill. Most of the 

 corn was killed early in the season, and the few stalks 

 left were dying a lingering death without producing any 

 grain. 



I was told that the insect was first noticed there about 

 nine or tcu yours previously, and that, about every third 



