SPECIAL NOTE TO EXTENSION ADVISERS 



Several have asked about methods of counting corn rootworm larvae. One method is 

 to spread a piece of canvas on the ground, dig up a corn plant along with the 

 soil in a 6 -inch square about 4 to 6 inches deep, and examine the soil carefully 

 by sifting it through your hands several times. Then tear up and split the roots, 

 also looking at the debris which has fallen off the roots. 



A second method resembles the first. Examine the soil, but cut off the roots and 

 place them in a plastic bag. Look for worms that will leave the roots at 24-, 

 48-, and possibly 72-hour intervals. 



A third system is to examine the soil in the field and save the roots. Place 

 them on hardware cloth over a bucket, having first placed a piece of moist paper 

 in the bottom of the bucket. Keep this moist and examine for worms at the end of 

 48 hours. 



A fourth, the flotation method, is to mix a pound of salt per gallon of water. 

 Place this in a bucket and put the dirt and roots still attached to the base of 

 the plant in this salt solution. Any salt will do- -it does not have to be table- 

 grade. Swish the roots and soil around several times. The rootworms will soon 

 float to the top with the debris and foam. Sometimes this is an excellent method 

 and \\'orks perfectly. At other times, the worms get mixed in with the debris which 

 must be examined carefully several times. After the count is made, the salt water 

 could be strained into another bucket and reused at least a few times. One problem 

 is disposal of this concentrated salt solution. Do not dump it in the field. 



Interpretation? If the worms are still very small, and hatches just starting, 

 and you find 4 or 5 per plant, make a basal application. Later when the worms 

 are larger and hatch has progressed, 10 to 15 worms are needed to necessitate a 

 basal treatment. 



READ THE LABEL AND FOLLOW ALL PRECAUTIONS 



This weekly report was prepared as follows: 



Insects: H.B. Petty, Steve Moore, Roscoe Randell, Don Kuhlman, and Stephen 

 Sturgeon, University of Illinois College of Agriculture and Illinois Natural 

 History Survey. 



Cereal Leaf Beetle: T.J. Lanier, USDA, Plant Pest Control. 



Bees: E.R. Jaycox, Department of Horticulture. 



Plant Diseases: M.P. Britton, Department of Plant Pathology. 



Weeds: Ellery Knake, Department of Agronomy; J.D. Butler, Department of 

 Horticulture. 



Ag Communications : Del Dahl . 



The information for this report was gathered by these people, staff members, 

 county Extension advisers, and others, in cooperation with the USDA Agricultural 

 Research Service, Plant Pest Control Branch. 



