-2- 



emergence of the moths is complete in the south-central section, three - fourths complete 

 in north-central Illinois, and just beginning in the northern area. 



If treatment is needed in southern Illinois, this would probably be applied during the 

 week of June 8. Cool temperatures can slow-down borer development, allowing the corn 

 plants to reach a more desirable height. If corn is 50 inches tall (leaves extended) 

 or more by the week of June 8, and if at least 75 percent of the plants show any whorl 

 feeding, apply carbaryl (Sevin) or diazinon as granules. 



Rootworm eggs have already begun to hatch. If you plan to apply a basal application 

 of soil insecticide, this should be done immediately; if possible, also cultivate in 

 order to incorporate the insecticide. We have had many questions about the effect of 

 heavy spring rains on planting-time treatments of soil insecticides. The insecticides 

 we have suggested for 1970 performed well during 1969 under heavy rainfall conditions. 

 We expect the same to be true this season. 



SMALL GRAINS AND GRASSES 



Armyworms can still be found in many wheat fields in southern and central Illinois. The 

 greatest number is along the eastern side of the state. One disease and a number of 

 parasites are killing many of the worms. In some localities, armyworms have migrated 

 to corn fields from wheat fields or grass areas. Although no report of cutting-off 

 wheat heads has been received, this could happen as the wheat begins to ripen. 



To determine the need for treatment, strike the plants vigorously, then count the worms 

 on the ground or in the debris- -even in the cracks and crevices in the row. If the 

 average count is 6 or more worms per linear foot of drill row throughout the field, 

 apply an insecticide when the worms are about 3/4 of an inch long. An armyworm eats 

 39 linear inches of wheat leaf in its lifetime, but 80 percent of that feeding occurs 

 after the worm is over 5/4 of an inch long. Leaf feeding is not serious when worm 

 populations are low, but an average population of less than 6 worms per linear foot 

 of drill row can still be damaging if the worms are cutting off the heads of the 

 wheat. Also if most worms are about 1-1/4 to 1-1/2 inches long and are fat, they are 

 through feeding. Do not use insecticides then; it is too late. 



Treatment is justified if there are six or more armyworms per foot of drill row, as 

 an average over the field. Applications of 1 to 1-1/4 pounds of malathion, 1 pound of 

 trichlorfon (Dylox) , 1-1/2 pounds of carbaryl (Sevin), or toxaphene will control army- 

 worms. Do not apply carbaryl on small grains after the boot stage. Do not feed for- 

 age or straw treated with toxaphene or trichlorfon to dairy cattle, livestock being 

 fattened for slaughter, or poultry. There is no waiting period between the appli- 

 cation of toxaphene and grain harvest; a week is required when applying malathion, 

 21 days for trichlorfon. 



Remember, toxaphene is very toxic to fish. Do not use it near fish-bearing waters. 

 If there are honey-bee colonies adjacent to fields to be treated, toxaphene is the 

 safest of the four to use. Carbaryl is the most dangerous one to use around bees. 



Where there is migration into corn, spray the infested rows as well as a 25- to 30-foot 

 strip of wheat adjacent to the corn. 



CLOVER AND ALFALFA 



Alfalfa weevil damage is common in many unmowed fields in the central section of the 

 state. In the southern third of Illinois, weevil activity has slowed down very much. 

 Some newly-mowed fields show damage to the new growth of the second crop. It is better 

 to cut the first crop and spray the new growth before it is damaged. 



