SHADE TREE INSECTS 59 



The time spent in the egg stage varies from a little over a week to more than 

 a month. The tiny grubs usually feed the first season on both decaying and living 

 vegetable matter in the soil. With the approach of cold weather they burrow 

 deeper into the ground and remain there through the winter. The following spring 

 they return near the surface and feed on the roots of plants. It is at this time 

 that the grubs do the greatest damage. In the fall they again burrow deeper into 

 the soil to spend the second winter. The next spring they return near the surface 

 and again feed on plant roots. Thus two years are spent by the grubs in the 

 soil. In the early summer the individual grubs of many species prepare an earthen 

 cell in the ground in which they transform to a pupa. (Some species may trans- 

 form to a pupa the following spring.) In a few weeks the pupae transform to 

 adults but remain in the pupal cell until the ne.xt spring when they emerge from 

 the ground. 



Although the complete life history takes three years, there is an emergence of 

 beetles every year. The emerging beetles of each year are designated as "broods" : 

 for example, Broods A, B, and C, each brood recurring at a 3-year period. In 

 some localities only one of these broods may be important so that an abundance 

 would recur at 3-year intervals. 



Control. Many white grubs in rough pastures and in meadows may be destroyed 

 by plowing and disking deeply one to four times in the early fall before the grubs 

 burrow deep into the soil for the winter. This treatment breaks up the soil, 

 disturbs the insects, and exposes them to the elements and to predatory animals. 

 If hogs or chickens are allowed to range on the newly plowed ground they will aid 

 in the destruction of the grubs. 



The beetles prefer to lay their eggs in grassland or in fields of small grain. 

 Such areas, therefore, should be regarded with suspicion. If many grubs are 

 present, the land should be plowed and disked, as mentioned above, to prevent 

 injury to an^' crop which is to be planted there the following year and to prevent 

 the beetles from emerging in numbers to attack the foliage of near-by trees. 



Rotation of crops is important in avoiding white grub injury. For egg laying 

 the beetles prefer land covered with grasses, small grains, or weeds rather than land 

 which is in clean cultivation, in corn or a pure stand of clover; so that even in a 

 year when the beetles are expected to be abundant the latter type of land ordinarily 

 will contain few grubs. 



The foliage of preferred host shade trees may be protected against the beetles 

 by a thorough spray of lead arsenate at the rate of 4 pounds to 100 gallons of water 

 with \}i pints of fish oil or raw linseed oil added as a sticker, if desired. 



Under certain conditions the beetles may be collected or jarred from the foliage 

 of some plants, caught in a large cloth, and then destroyed by being dropped into 

 a can containing kerosene and water. Best results are usually obtained by col- 

 lecting beetles in early morning when they are easily jarred from the trees. This 

 should be done at the beginning of the flying season so as to destroy as many 

 female beetles as possible before they lay many eggs. 



To destroy grubs in lawns and to grub-proof lawns against this beetle, one 

 may use the same measures advised for Japanese beetle larvae. 



Davis, J. J. U. S. Dept. Agr. Farmers' Bui. 940. 1918 (Rev. 1929). 



Fernald, C. H. Hatch Exp. Sta. Mass. Agr. Col. Bui. 12:14-16. 1891. 



Forbes, S. A. Univ. 111. Agr. Exp. Sta. Bui. 186. 1916. 



Forbes, S. A. Univ. 111. Agr. Exp. Sta. Bui. 187. 1916. 



Gibson. A. Can. Dept. Agr. Bui. 99 (N. S.): 48. 1934. 



Hammond, G. H. Ent. Soc. Ont. Rpt. 64:47-52. 1934. 



Pettit, R. H. Mich. Agr. Exp. Sta. Circ. Bui. 132. 1930. 



Richter, P. O., and Fluke, C. L., Jr. Jour. Forestry 33(6):620-621. 1935. 



