74 BULLETIN 479, U. S. DEPARTMENT OF AGRICULTURE. 



near the surface of the soil. They feed at night, concealing them- 

 selves in the soil or under rubbish during the da} 7 . Scratching the 

 soil about an injured plant to a depth of one or possibly two inches 

 usually reveals the worms, and this method of hand destruction of 

 the larvae may be practiced in small areas where the infestation is 

 scattering. 



Cutworms may be destroyed also by means of a poisoned bait 

 prepared and applied as follows: Mix T>0 pounds of bran with 4 

 pounds of lead arsenate and 2 gallons of low-grade molasses until 

 the mass is made into a stiff dough. The chopped oranges or lemons 

 mentioned in the bulletin referred to (see footnote) are not always 

 essential, but the molasses is absolutely so. In semiarid regions it 

 is advisable to add water to prevent rapid desiccation and to dis- 

 tribute the bait toward evening. About a tablespoonful of the bait 

 should be placed every foot or two along the nursery row. In case' 

 of migration from an adjoining field, the nursery ma} 7 be protected 

 by running a narrow band of the poisoned bait entirely around the 

 edge or along the side nearest the source of infestation. A ditch 

 constructed around the Savenac Nursery proved somewhat effective 

 in trapping some of these larva? which were migrating from an ad- 

 jacent clover field. 



WHITE GRUBS. 1 



"White grubs, the larva? or young of beetles commonly known as 

 May beetles or " June bugs," are often a serious menace to nursery 

 stock, especially conifers, injuring or killing the seedlings and 

 transplants by cutting off the smaller and girdling the larger roots. 

 Most of the May beetles have a three-year life cycle, and except the 

 one or two months (usually May and June) during which the beetles 

 appear above ground to mate and feed, this entire period is spent 

 underground, and two years of the three are spent in the grub stage. 

 In the extreme northern limits of the United States, that is, in 

 northern Wisconsin and Minnesota, where the grubs are important 

 enemies of conifer seedlings and transplants, this insect has a four- 

 year cycle, due to the shorter seasons. The grubs occur at various 

 depths in the soil, and their proximity to the surface is largely 

 dependent on the temperature and moisture conditions. They are 

 found deeper during the winter months and more often quite near 

 the surface in early fall. Plowing or cultivating the soil at this 

 time, therefore, is of value, especially if done the year following the 

 most severe summer injury, which would be the season the insects 

 are transforming from grubs to beetles, at which time disturbances 



1 For further information on these insects, see U. S. Dept. Agr. Farmers' Bulletin 

 543. 



