ENTOMOLOGY 83 



like stages, kerosene emulsion diluted with twelve parts of water 

 seems to be most effective ; but it must be applied with a bent nozzle 

 so as to hit the underside of the foliage. If adults are flying when 

 the application is made, a fine spray is desirable, for this, if applied 

 with sufficient force, will fill the air above and around the plants 

 with a fine mist that will hit and disable many of the insects on the 

 wing. Whale oil soap suds, one pound in six gallons of water, has 

 also been used with good effect in the same way. 



A badly infested patch should never be used as a source for 

 plants to make a new bed, unless these plants are first fumigated 

 with hydrocyanic acid gas. (Bui. 225, N. J. Agr. Exp. Sta.) 



White Grubs (Larva of June Beetles). White-grubs are larvae 

 of May-beetles, or June bugs, the clumsy brown beetles about an inch 

 long, that fly to light and often into nouses in late May and early 

 June. These beetles lay their eggs in grass lands or land covered 

 with vegetation to form a sod of some kind. They hide during tho 

 day just below the surface in such grass or weed-covered land, and 

 do not by choice frequent cultivated land except to feed on such 

 foliage as may be attractive to them. Old sod or land left fallow for 

 some years becomes continually \vorse infested as brood after brood 

 of eggs are laid in it. From the eggs laid in June the small white 

 grubs hatch in July and begin feeding on the finer rootlets. They 

 do not grow very much that first season and are less than half an 

 inch long when winter sets in and they retire below the ordinary 

 frost line. The next season they feed from May to October on the 

 roots of the plants, usually about three to four inches below the sur- 

 face, and when winter sets in again, they are an inch in length and 

 stout in proportion. The third summer they complete their growth 

 in July, and, at about six inches below the surface, form an oval, 

 smooth cell in which they change to the pupal stage. This pupal 

 stage lasts about a month and gradually hardens into the adult or 

 beetle, which is in the cell, fully formed but not fully colored, in 

 September. 



It will be readily seen that after a plot is in sod for three years 

 the ground will be full of grubs in all stages of growth, and that 

 every year thereafter the number of full-grown larvae is likely to 

 increase. When such a sod is turned under and another crop is 

 planted, that crop almost inevitably suffers, for the insects deprived 

 of the mat of roots upon which they have been feeding, concentrate 

 on the small number of plants and the result is fatal. 



We have no satisfactory insecticides to reach underground in- 

 sects. They have their natural enemies among the vertebrates 

 birds, moles and the like as well as insect parasites and fungous 

 diseases, but these do not keep down the insects to harmless numbers. 

 It is in farm practice that our hope of control lies. In the first place 

 keep land in grass or fallow as short a time as possible consistent 

 with the desired rotation and never allow a field to become badly 

 overrun by weeds early in the season if it can be avoided. 



In case it is necessary to use an old sod, plow in early fall. 

 Although the white grubs change to beetles in September they are 



