THE FOREST NURSERY 355 



Sulphur, when used on coniferous seedbeds in New England, 

 has resulted in rather serious harm to the plants. Kerosene-soap 

 emulsion has also caused some injury. The best results have 

 been obtained with a nicotine product, a commercial preparation 

 known under the name "Black leaf 40. " One pound of the prep- 

 aration will make from 160 to 400 gallons of spraying solution. 

 From 3 to 4 pounds of good laundry soap or whale oil soap should 

 be added for each 100 gallons of the solution. 



Among insects which infest the soil those most harmful to 

 nursery stock are the common white grubs, viz., the larvae of a 

 number of species of Lachnosterna usually known as May beetles. 

 The species of Lachnosterna are widely distributed over the 

 United States and some species are present in nearly all nurs- 

 eries. The species most injurious in the New England states 

 are: L. crenulata, Forst.; L. fusca, Froh.; L. fraterna, Harris; 

 L. hirticula, Knoch. ; and L. nova, Smith. 



The adult beetles feed chiefly on broadleaved trees. The large, 

 white larvae live in the ground and feed upon the roots of various 

 plants. They often occur in great numbers, are ravenous feeders 

 and require several years for full development. They are particu- 

 larly abundant on areas covered with sod or weeds. When such 

 areas are plowed and seedbeds or transplant beds immediately 

 formed the insects transfer their damage from the roots of the 

 grass and weeds to the young trees and do a vast amount of 

 damage. The usually light, porous soil of seedbeds affords special 

 attraction to the female beetle when laying her eggs. The damage 

 to forest nurseries in the United States has been confined chiefly 

 to transplant beds where the soil has not been thoroughly tilled 

 for a year before the formation of the beds. The evidence of 

 damage is shown by the young plants turning yellow and finally 

 dying as the roots are eaten off. If close watch is kept of infested 

 beds and the plants dug up as soon as the first evidence of injury 

 is apparent, the larvae are usually found close to the destroyed 

 roots. This method of destroying the pest is the one usually 

 practiced in forest nurseries in the United States. It is expen- 

 sive and only partially successful. 



Nurseries surrounded by stands of hardwood trees are particu- 

 larly subject to damage by the larvae of May beetles as the adult 

 insects feed upon the foliage and swarm over the adjacent nursery 

 beds at the time the eggs are deposited in the soft soil. 



