- 2 - 



mixture is applied around the. trees. 



Mechanical agitation cannot be provided as easily as jet agitation. Jet 

 agitators have been developed which can be connected to the pressure line between 

 the pump and the by-pasS valve. The agitation consists of a head with three 

 orifices from which streams of spray solution are expelled. It is suspended by a 

 hose to the bottom of the tank. where the expelled streams agitate the spray 

 suspension. 



Herbicides should not be applied with a high-pressure spray rig unless It is 

 modified. The equipment should have an operational pressure of 30 to 40 pounds 

 per square inch. Low pressure and low gallonage rates help avoid forcing the 

 spray into the soil - a common cause of herbicide injury. 



There are two basic types of general farm sprayers - boomless and boom 

 equipped. Either of these are available with a variety of pumps and carriers and 

 can be tractor or trailer mounted. The boom sprayers in common use would have to 

 be modified for, orchard grass control because of the limited area to be covered. 



Herbicides 



Bearing Apple Orchards 



1. Dalapon - Recommended for control of grass under apple trees at least 4 

 years old. Use Dalapon at the rate of 1 pound to 10 gallons of water. Apply 10 

 pounds of Dalapon per acre on the area treated. The grass should be sprayed when 

 it is 4 to 6 inches high which is usually in May. Re-treat later if necessary. 



2. Diuron - Recommended for control of certain seedling annual weeds. Use 

 only under trees which have been established in the orchard for at least i year. 

 Do not use under dwarf or semi-dwarf trees. Apply at the rate of 4 pounds of 

 Diuron per acre of treated ground area. Continuous agitation is required to keep 

 Diuron in suspension. Apply in the early spring prior to germination and growth 

 of annual weeds-. 



3. Dalapon plus Diuron - Dalapon controls the grass but has no practical 

 effect on weeds. The combination should insure more complete grass control and 

 will control many weeds that are likely to take oi/er where the grass has been 

 subdued. Apply either 10 pounds of Dalapon plus 4 pounds of Diuron or 5 pounds 

 of Dalapon plus 4 pounds of Diuron per acre on the area treated. According to 

 Prof. 0. F. Curtis, Geneva Experiment Station, whether Dalapon is advisable at 10 

 pounds rather than 5 pounds when applied with Diuron will depend in part of the 

 grower's attitude. "If he is anxious to depend on one single spray treatment in 

 the spring, the 10 pound rate of Dalapon is likely to be more effective than the 

 5, but if he is willing to undertake a second spray application, if needed, he 

 may make better use of [)alapon by using 5 pounds with the Diuron. If this is not 

 effective (i.e., the grass is still growing in height 2 to 3 weeks after treat- 

 ment), then a repeat Dalapon treatment can be used. Even after apparently 

 effective control early in the season, regrowth of quack grass sometimes begins 

 in August and having the second 5 pound application to use at this time can be 

 helpful." 



4. Simazlne - Apply Simazine (80 per cent wettable powder) at the rate of 



