The greatest possibility of milk contamination from use of aldrin or heptachlor as 

 corn soil insecticides exists in use of harvested cornfields as a grazing or rest- 

 ing area for dairy cattle. As the animals contact the treated soil and pick up 

 corn from the ground, they pick up soil containing sufficient insecticide to be de- 

 tectable in the milk. Use of aldrin or heptachlor as corn soil insecticides does 

 not present a residue problem in the grain. Corn for ensilage or stover should be 

 cut about 18 inches above the ground, if soil treatments of aldrin or heptachlor 

 have been used. Hay produced even 2 years after the last soil application may have 

 slight residues from contaminated soil particles. 



When buying corn ensilage or other forage, be sure it does not have an objection- 

 able residue. Question the supplier; if in doubt, have a chemical analysis made. 

 These statements apply to heifers and dry cows, as well as producing cows. 



Do not apply these chlorinated hydrocarbons to dairy buildings or barns or on dairy 

 cattle. 



Toxaphene is a chlorinated hydrocarbon not included in the above list. It will ap- 

 pear in the milk when dairy animals eat toxaphene- treated forage; however, it is 

 not stored in the animal's body, and they will produce clean milk in about 1 week 

 after exposure. A dairyman may wish to use toxaphene on his farm to control insect 

 pests of soybeans, corn (for grainj , or small grain providing he does not use them 

 for pasture, hay, ensilage, or stover. In using toxaphene, the dairyman should 

 take all precautions to avoid drift onto dairy pasture, hay, or other forage crops. 



SOYBEAN FARMS 



Recent research shows that aldrin and heptachlor (and their breakdown products, 

 dieldrin and heptachlor epoxide) are translocated to the beans grown in the field 

 the year of application. This research also shows that soybeans following corn, 

 to which the soil insecticides aldrin and heptachlor have been applied, absorb small 

 but still-detectable amounts of these insecticides. 



On the basis of preliminary research and guided by the results of random surveys 

 of Illinois soybeans, we suggest to Illinois soybean producers the following uses 

 of insecticides in 1968: 



1. Do not use the soil insecticides, aldrin, chlordane, dieldrin, endrin, hepta- 

 chlor, or lindane as a soil or foliar treatment for soybeans. Aldrin, dieldrin, 

 and heptachlor are not cleared for use on soybeans as a foliar treatment. DDT 

 was granted a tolerance in soybeans, but we do not recommend that it be used 



by Illinois farmers. 



2. At present, allow 2 years to elapse after the last application before planting 

 soybeans in a field where either aldrin or heptachlor have been applied annually 

 for 5 or more years. Thus, if aldrin or heptachlor were applied to a field from 

 1963 through 1967, skip 1968; and do not grow soybeans in this field until 1969. 



3. For the common Illinois rotations (which include soybeans, corn, and grains), 

 continue to plant soybeans as you have in the past. The future of this sugges- 

 tion depends on research and survey data. 



