"** I 



COLLEGE OF 

 AGRICULTURE 

 UNIVERSITY OF 

 ILLINOIS AT 

 U R B AN A-CH AM P Al G N 

 AND NATURAL 

 HISTORY SURVEY 

 URBANA, ILLINOIS 



NSECT WEED & PLANT DISEASE SURVEY BULLETIN 



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



3R IMMEDIATE RELEASE 





l<& 



: 



2 







No. 12, June 13, 1969 



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

 Isease situation (fruit and commercial vegetables excepted) , along with suggested, ab- 

 breviated control measures. Each individual should check his own fields to determine local 

 editions . 



INSECTS 



DRN INSECTS 



ged-corn beetle damage is still being reported to us. Plant stands are erratic, and plants 

 ary greatly in size. Since these beetles have eaten the food stored in the seed, the small 

 prout dies before it emerges; or if it does emerge, the seedling is weakened. Therefore, 

 lere are normal plants in the field, weak plants less than half normal size, plants that 

 ave never emerged, and seeds that did not germinate. Variation in size can also be due to 

 ertilizer burn, wind, fungus infection, and planting -depth differences. However, if the 

 eed was definitely hollowed out, the damage is probably seed beetle. Seed-beetle damage 

 as been observed where no treatment was applied, as well as where aldrin or heptachlor 

 ad been used as soil insecticides . 



arn blotch leaf miners are becoming more common. They are not of economic importance, but 

 an be confused with other problems. The adult, which is a fly, makes tiny elongated punc- 

 ures in groups about 1/16-inch long- -usually in the tip of the leaf. The maggot mines 

 stween the upper and lower leaf surfaces . A dirty-yellow maggot can usually be found in 

 tiese mines . 



ommon stalk borers are now appearing in cornfields and can be expected to appear in many 

 rops--oats, wheat, corn, tomatoes, and many flowers --during the next three weeks. Although 

 tiey are still only 1/4-inch long, the distinctive coloration is noticeable. They have 

 ellow-to-white stripes running lengthwise along the body. The middle section of the body 

 5 purple, black, or brown; both ends are lighter colored. 



hese pests usually infest crops near fence rows, ditch banks, grass waterways, or any 

 ther area where weeds were present for the moths to deposit eggs last August. These eggs 

 re now hatching, and the worms are migrating to the nearest plants. 



ontrol is rarely recommended, since these worms usually remain on one plant and do not 

 igrate throughout the field- -contrary to the impression held by some people. 



orn flea beetles are tiny, black, shiny beetles found on com leaves. They jump at the 

 lightest disturbance, so approach the plants cautiously if you want to see them. The 

 eetles strip tiny areas from the surface of the leaf. The tiny "scratches" are parallel 

 o the leaf veins. Although not numerous enough to be damaging, these beetles transmit 

 tewart's disease of corn, No control on field corn is practical for these insects unless 

 hey are killing plants. 



