For the next 4 weeks, examine silks and plants every week for the green, northern 

 corn-rootworm beetles or the striped, western corn-rootworm beetles. You are 

 most likely to find western rootworm beetles already in second-year cornfields, 

 where they will lay eggs for next year's crop of rootworms. Northern rootworm 

 beetles will be most common in fields where corn has been grown for two or more 

 years successively. They will also migrate, and will occasionally be found this 

 fall in fairly large numbers in first-year cornfields. 



If you find no beetles, it is unlikely that you will have rootworm problems next 

 year. If you find beetles, this does not necessarily mean you will have rootworm 

 problems next year, but the odds are that you will. Egg laying is underway right 

 now . 



How many beetles should you find to predict problems next year? We do not know; 

 but 1 per plant is a start, and 5 per plant can lead to serious problems. If 

 you find this many, plan on using one of the phosphate or carbamate insecticides, 

 because all rootworms in Illinois can now be considered resistant to aldrin or 

 heptachlor. 



If the western corn rootworms have not been reported from your county, please 

 send suspicious -looking beetles to us. See your Extension adviser in agriculture 

 for a list of counties where this pest has already been found. The western corn 

 rootworm was found for the first time in Mason and Logan counties this week. 



Corn leaf aphids are about as conspicuous now by their absence as they were by 

 their presence a few weeks ago. Winged aphids have been migrating from infested 

 fields as soon as they reached the dry-silk stage. Huge numbers of these winged 

 aphids have infested the whorls of late corn, where some build-up of wingless 

 offspring may occur. In general, however, the aphid problem is disappearing. 



Fall armyworms are appearing in very late-planted corn that is just now in the 

 whorl or very- early- tassel stage. These grey to brown worms can be found deep 

 in the whorl. As the partially damaged leaves emerge, they are very ragged. 



Damage is most common in patches or areas in the field; the female moth will 

 deposit a cluster of several dozen eggs on one leaf. As they hatch, the tiny 

 worms migrate or are blown onto adjacent plants- -thus affecting several plants 

 in the one spot. 



Usually, yields are not seriously affected. Sometimes, however, these worms enter 

 the ear and stalk. They are damaging if they feed extensively in ears. Although 

 this is usually not the case, it can occur. 



Control is difficult, since the worms are either deep in the whorl or in the ear 

 before they are discovered. Carbaryl (Sevin) or toxaphene granules will help 

 control them in the whorls; carbaryl sprays will help prevent ear infestations, 

 but will not control the worms after they are deep in the ear. 



SOYBEAN INSECTS 



Green cloverworm populations continue to decline. The fungus disease that has 

 killed them apparently is now widespread in the state, and the worms have 

 disappeared rapidly. Beans should soon mature enough that reinfestation would 

 not seriously affect yields. 



