- 523 - 



in Monroe County showed light infestation by third instars in lateral shoots. 

 (Newman). Found in field corn, especially in central areas. Most larvae in whorls 

 or in stalks. Some pupation. New adults will emerge next 14-21 days. Heavy and 

 spotty in field corn in Kent County (Knisely) and Shiawassee County (Austin) , 

 (Sauer) . INDIANA - About 50 percent of fields usually visited during fall corn 

 insect survey in southern area examined for first-generation Ostrinia nubilalis 

 infestations. Percent infestation as follows: Southwest - 12.4 (range 0-36) In 

 9 fields with average of 9 (range 0-16) larvae per 100 stalks; south-central - 

 6.8 (range 0-20) in 7 fields with average of 8.6 (range 0-28) larvae per 100 

 stalks; southeast - 7.5 (range 0-24) in 8 fields with average of 5.5 (range 0-20) 

 larvae per 100 stalks. More than 2 larvae in single stalk observed only once; 

 all ages of larvae frequently found in single fields. (Meyer), WISCONSIN - 

 Blacklight trap collections light at all reporting sites. Larvae in all stages of 

 development. Surveys showed 80 percent infestation near Endeavor, 32 percent at 

 Westfield, 32 percent at Weyauwega, 56 percent at Hancock, 1 percent at Horton- 

 ville, 1 percent at Green Bay, 48 percent at West Salem, 40 percent at Eau 

 Claire, 10-70 percent in Dodge County, and up to 100 percent at some sites in 

 Trempealeau and Adams Counties. (Wis. Ins. Sur.). MINNESOTA - Average number 

 infested plants (average number of borers) per 100 plants by district: Southwest 

 36 (72), west-central 61 (204), central 55 (161), east-central 17 (41). (Minn. 

 Pest Rpt.) . 



NORTH DAKOTA - 0. nubilalis light in southeast grain corn producing counties. 

 Shotholing in 513 percent of fields checked in Richland, Dickey, and Barnes 

 Counties; 0-25 percent of plants infested. Egg masses still in Richland County. 

 Most borers in second instar. (Brandvik) . SOUTH DAKOTA - Continues to infest corn 

 in eastern areas. Adults abundant and oviposition noted in northern Moody County 

 and into Brookings County. Infestations of 100 percent in some fields in Sanborn 

 and Beadle Counties. Mostly in whorls. In heavily infested counties, infestations 

 100 percent in some grain sorghum. Borers in sorghum not expected to survive. 

 (Jones, July 9). IOWA - First-brood survey completed in 32 randomly selected 

 cornfields in Boone County July 12-13. In each field, 26 plants dissected. Borers 

 62 per 100 plants with 63 percent of plants infested. Survey showed 10,813 borers 

 per acre which compares to 3,271 per acre in 1970, (Iowa Ins. Sur.), NEBRASKA - 

 Infested plants ranged 34-49 percent with 0-3 third to fifth instars per plant 

 in 4 Furnas County fields, (Keith), First generation beginning to pupate at Mead, 

 Saunders County (Munson) , MISSOURI - Last instars, pupae, adults, and eggs found 

 in northern areas. Moth flights probably at peak in southeast area. (Houser) . 

 KANSAS - Recent blacklight trap catches indicate first-generation moths emerging 

 in Brown and Riley Counties, (Bell). 



WESTERN CORN ROOTWORM ( Diabrotica virgifera ) - COLORADO - Pupation about 30 per- 

 cent and some adult emergence in Logan County. (Donahue, Hantsbarger) . OKLAHOMA - 

 Adult emergence light in cornfields in Texas and Beaver Counties. (Okla. Coop. 

 Sur.). MISSOURI - Adults averaged 1 per plant in several fields in northeast area. 

 Averaged 5 in severly lodged cornfield in north-central area. (Munson). NEBRASKA - 

 Pupation 50-75 percent and adult emergence 15-25 percent in Saunders County. 

 Adults average about 4 per corn plant, mostly males, (Munson). 



NORTHERN CORN ROOTWORM (Diabrotica longicornis ) - TENNESSEE - Adults averaged 6 

 per ear of early planted corn in Weakley County, This is a new county record. 

 (Pless, Eisler) . INDIANA - Adults (counts usually very low) present in occasional 

 field of corn in southwest, south-central, and southeast districts. Averaged 4 

 per plant in field beginning to silk in Hamilton County. (Meyer). 



CORN ROOTWORMS (Diabrotica spp.) - OHIO - Larvae peaked this period. Adults of D. 

 longicornis (northern corn rootworm) and D. undecimpunctata howardi (southern 

 corn rootworm) appearing. (Musick) . SOUTKTdAKOTA - Diabrotica spp. larvae severely 

 damaged corn in Freeman area of Hutchinson County; some damage in fields treated 

 at planting time. Larvae damaged corn near Renner, Corson, and Garretson in 

 Minnehaha County. Damage to corn in these localities attributed to low degree of 

 control from misapplication of insecticides at planting time. Damage heavy in 

 Moody County. Heavy in 45-acre field of untreated corn. In same area, heavy in 15 

 acres of corn planted previously in Sudan grass in 1970. (Kantack) . 



