-2- 



a few eggs have hatched. If the corn is in the whorl stage and if 75 percent or more of 

 the plants are showing recent whorl feeding, apply carbaryl (Sevin) or diazinon as gran- 

 ules or sprays. Aerial sprays on tasseled corn are effective; but on whorl-stage corn, [ 

 aerial applications should be granules and not sprays. Direct ground -applied sprays into 

 the whorl of whorl-stage corn, and from the ear zone upward in tasseled corn. Use 1-1/2 

 pounds of carbaryl or 1 pound of diazinon per acre. Wait 10 days after applying diazinon 

 before ensiling the corn. No waiting period is required for carbaryl. 



In late-maturing sweet corn, apply an insecticide every 3 to 5 days if there are 20 

 or more unhatched egg masses per 100 plants and the corn has a tassel ratio of 30 or 

 more. For corn in silk, spray at the ear zone every 3 to 5 days to protect against 

 both corn borer and corn earworm. The addition of 0.5 to 0.75 pound of parathion to 

 the 1-1/2 pounds of carbaryl applied per acre improves earworm control. Allow 12 days 

 between the last application of parathion and harvest. 



Fall armyworms continue to damage late-maturing corn, particularly in the southern 

 half of the state. Infestations will continue until fall as new generations are 

 produced. Generally, the damaged plants are not killed but recover and produce a 

 near normal yield. Therefore the benefits from control have been somewhat question- 

 able. However, if 20 percent or more of the plants are infested and the worms are 

 less than 1-1/4 inches long, control is probably justified. A full-grown fall army- 

 worm is about 1-1/2 inches long when it ceases to feed. Yellow-striped armyworms, 

 corn earworms, and cat- tail caterpillars are also present in some fields. 



Carbaryl, Gardona, or toxaphene at 1-1/2 pounds per acre or diazinon at 1 pound are 

 effective. Sprays are effective when they reach the worms. If the worms are deep 

 in the whorl, granules are generally more effective. Wait 5 days after applying 

 Gardona and 10 days after applying diazinon before ensiling the corn. Do not feed 

 toxaphene -treated corn as forage to dairy cattle or livestock fattening for slaughter. 



Corn rootworms. The adults are becoming more numerous as they continue to emerge from 

 the soil. The yellowish to pale-green northern rootworms, the yellow and black-striped 

 western worms, as well as the twelve -spotted southern corn rootworms, feed on fresh 

 silks. They can interfere with pollination and reduce kernel set. 



Continue to check fields coming into fresh silk, particularly in the northern half of 

 the state. If there is an average of 5 or more of these beetles per plant and if the 

 field is not over 50-percent silked, treatment is justified. Apply carbaryl (Sevin), 

 malathion, or diazinon at 1 pound of actual chemical per acre. There is no waiting 

 period between application and harvest for carbaryl. Allow five days for malathion 

 and ten days for diazinon. 



Count the number of beetles per plant for the next three to four weeks. When the aver- 

 age is one or more beetles per plant each week, the field may profit from a soil insec- 

 ticide treatment next spring, if the field is planted in corn. 



HOMEOWNER INSECTS 



Second -gene rat ion sod webworm moths have been emerging and laying eggs in lawns . This 

 egg-laying will continue for several more weeks. Apply ample fertilizer and water to 

 the lawn to help lessen the possibility of serious damage by these insects. Once 

 started, this program must be continued to avoid serious damage. If needed, an appli- 

 cation of carbaryl (Sevin) , diazinon, or chlorpyrifos (Dursban) as a spray or granules 

 will effectively control the worms for a week or two. Use 3 to 4 gallons of water per 

 1,000 square feet of lawn area. A good time to apply the treatment is about two weeks 

 after a heavy moth flight. An additional treatment may be needed if egg- laying con- 

 tinues heavy into late August. 



