-3- 



Bronze birch borer adults are emerging from the upper limbs of birch trees. The bronze 

 beetles will lay eggs on roughened bark on the upper part of trees. Good control of 

 this borer can be achieved if the trunk and limbs are sprayed with dimethoate (Cygon, 

 De-Fend) as the eggs start to hatch. Use 1 cup of the 2 -pound-per- gallon formulation 

 per 25 gallons of water. Begin about May 25 in southern Illinois, June 1 in the cen- 

 tral section, and June 7 in the northern area. Repeat the dimethoate spray three weeks 

 later. Spray only those trees that are infested. 



Bagworms are hatching in southern Illinois , and will be hatching in the central sec- 

 tion by June 10. These tiny worms can defoliate evergreens such as junipers, as well 

 as some shade trees. As they feed, these worms construct a spindle-shaped bag in which 

 they live. In the southern section, sprays can be applied now. The target date for 

 spraying in the central area is after June 15; in the northern section, after June 30. 

 Control bagworms while they are small and easy to kill. Once the bagworms become half- 

 grown or more, insecticide spraying often fails. 



For control, apply a spray containing carbaryl (Sevin) , diazinon, malathion or Baailus 

 thwingiensis (Biotrol , Dipel, Thuricide and others). Follow the directions on the 

 label. Check carefully for plants that could be injured by the insecticides used. 



Bean leaf beetles are beginning to chew holes in leaves of green beans. Some of these 

 brown, yellow or dull -red, beetles have no black spots; others have two or four spots. 

 Bean leaf beetles can be controlled easily with carbaryl (Sevin) , applied as a commer- 

 cially prepared 5-percent dust or as a spray containing 2 tablespoons of 50-percent 

 wettable powder per gallon of water. 



WEEDS 



SENCOR 



Sencor has been widely advertised, but supplies will be rather limited. Soybean tol- 

 erance to Sencor is also somewhat limited. Rates should be selected very carefully 

 for the soil. Applications should be very accurate and uniform. Sencor will not be 

 adapted to fields with wide variations in soils. 



There is a strong desire for improved broadleaf weed control in soybeans. Sencor has 

 the potential to provide this. But with only limited supplies available and the rather 

 close soybean tolerance involved, we would suggest trying Sencor on a test acreage this 

 year, in order to gain experience before using it on a large scale. 



Sencor can control most of the major broadleaf weeds found in soybeans, including cock- 

 lebur. It is not a good answer for annual morningglory. Sencor can also provide some 

 control of annual grasses, but a little higher rate is generally needed for grasses 

 than for broadleaf weeds. And as you increase rates, of course, the risk of soybean in- 

 jury also goes up. 



The label rates for Sencor for our area are 3/4 to 1-3/4 pounds of the 50-percent wet- 

 table powder per acre on a broadcast basis, depending on soil. NOTE: The manufacturer 

 recently lowered the recommended application rates. We would suggest going easy on 

 rates above 1-1/2 pounds per acre on Illinois soils. 



Combinations with reduced rates of Sencor plus a good grass killer to improve crop tol- 

 erance and grass control are possibilities for the future, but are not yet cleared. Reg- 

 istration for a Treflan preplant incorporated application followed by Sencor on the sur- 

 face is being requested. Registration for a tank mix of Lasso plus Sencor is also being 

 requested. 



