NURSERY PRACTICE ON THE NATIONAL FORESTS. 75 
are usually fatal to them. The value of plowing or cultivating a 
field is greatly enhanced if poultry have the run of the field and 
are encouraged to forage during these periods. Each locality 
usually has one brood predominating, and the history of the brood 
should be learned, thus permitting the practices of persistent hand 
collecting of the grubs and beetles, spraying trees whose foliage 
is favorite food of the beetles with an arsenical during the flight 
of the beetles, and careful tilling of the land to prevent grass and 
weeds from making a growth during such flight, all of which are 
helpful expedients. 
Grasshoppers are often a serious menace in nurseries, and have 
been so at the old Garden City and the Page Creek Nurseries. The 
best poison remedies recommended against these insects are the 
poisoned-bran bait, described above, and the modified Criddle mix- 
ture. The latter is prepared as follows: Fresh horse droppings, 
one-half barrel; lead arsenate, 2 pounds; finely chopped oranges or 
lemons, 6 to 8 fruits, all thoroughly mixed. For protection against 
these insects the bait is best distributed broadcast over the nursery, 
and especially around the outer borders or open side, as circum- 
stances may dictate. Fine screens around the seed beds and a brood 
of chickens at Trapper Creek have proved more effective than any- 
thing else tried. 
APHIDS. 
Under certain climatic conditions aphids are apt to appear in 
greater or lesser numbers and do a corresponding amount of dam- 
age. These insects feed by sucking the sap of the plants, thus 
checking their growth and lowering their vitality. A woolly aphid 
has seriously damaged Jeffrey, western yellow, and Austrian pines 
at the Converse Flats Nursery, and was worse on the first-named 
species. Kerosene emulsion is one of the standard remedies and 
is especially effective if applied early in the spring, before the 
insects have multiplied excessively and the woolly species have cov- 
ered themselves. 
Kerosene emulsion is prepared as follows: Take 2 gallons of 
kerosene, one-half pound of laundry or fish-oil soap, and 1 gallon 
of water; dissolve the soap in hot water, remove the solution from 
the fire, promptly add the kerosene, and agitate the mixture vig- 
orously for about 5 minutes until it becomes creamy — an emulsion. 
A most effective way of agitating the mixture is to pump it back 
1 For further information on the habits of these insects and methods of control, see 
U. S. Dept. Agr. Farmers' Bulletin 747. 
