COLLEGE OF 

 AGRICULTURE 

 UNIVERSITY OF 

 ILLINOIS AT 

 URBANA-CH AMPAIG N 

 AND NATURAL 

 HISTORY SURVEY 

 URBANA. ILLINOIS 



NSECT WEED & PLANT DISEASE SURVEY BULLETIN 



rATE/COUNTY/LOCAL GROUPS/U.S. DEPARTMENT OF AGRICULTURE COOPERATING 



FOR IMMEDIATE RELEASE 



No. 8, May 26, 1972 



This series of weekly bulletins provides a general look at the insect,weed, and plant 

 disease situation (fruit and commercial Vegetables excepted) , along with suggested, 

 abbreviated, control measures. Each individual should check his own fields to deter- 

 mine local conditions. 



I 



SMALL GRAIN INSECTS 



THE LIBRARY OE IHi 



NSECjflN 14 1972 



UNIVLKtoliY OF ILLINOIS 

 ATURBANA-CHAMPAIGN 



True armyworm populations are high in some of the thick, rank stands of wheat, bar- 

 ley, rye, and grasses in the southern half of Illinois. However, many of the sus- 

 pect fields we checked had only a few worms. Each field should be gone over sepa- 

 rately to determine the level of infestation. The worms we saw were mostly about 

 half grown, around three-quarters of an inch in size. There have already been some 

 migrations of armyworms from grasses and grains into corn. 



High temperatures produce a disease that can kill many of the worms within a few 

 days. Worms killed by this disease will often be seen stuck to the stem near the 

 top of the plant. As yet, only a few diseased or parasitized worms have been ob- 

 served. 



To count armyworms, shake the plants vigorously to dislodge the worms and count 

 those on the ground and in the dead leaves and other trash at the base of the 

 plant. Make counts in several places in the field. If you find an average of 6 

 or more worms per linear foot of row, an insecticide treatment is justified. Leaf- 

 feeding is not serious when the worm population is low; but when the average is 

 fewer than 6 worms per foot of row, damage can still occur if the worms begin cut- 

 ting the wheat heads . 



For control, apply 1-1/2 pounds of toxaphene per acre. Do not feed the straw to 

 dairy cattle, animals fattening for slaughter, or poultry. There are no restric- 

 tions on the use of the grain. One and one-half pounds of malathion per acre may 

 be used to within seven days of harvest, or 3/4 pound per acre of trichlorfon (Dy- 

 lox) to within, twenty-one days of harvest. 



Where worms are migrating into corn, spray the infested rows as well as a 25- to 

 30-foot strip of grass or grain adjacent to the corn. Also, watch fields in which 

 no-till corn has been planted on grass sod or after rye. Armyworm moths may have 

 deposited eggs in the grasses or rye and the worms will move readily to the small 

 corn. The insecticides used on wheat can also be used on corn. In addition, car- 

 baryl (Sevin) , used as a spray on com, will effectively control armyworms. 



CORN INSECTS 



Black cutworms have been reported damaging corn in the south-central and western 

 sections. Just a few scattered reports have been received. 



