-5- 



yellow, black, or red) suck the sap from plants and may cause the leaves to begin to 

 curl and dry. The aphids secrete a sugary, sticky material ("honeydew") that coats 

 the leaves, making them glisten. A black mold may develop when the honeydew deposits 

 are heavy. 



Ants feed on the sugary secretions of aphids, so a large number of ants on a plant 

 may be a sign that the aphids are numerous. Another "warning" signal is the presence 

 of white specks on leaves. These are the cast skins of the aphids. 



In most cases, aphids do little damage. If injury occurs, apply a spray using 2 tea- 

 spoons of 25-percent diazinon or 2 teaspoons of 50- to 57-percent malathion liquid 

 concentrate per gallon of water. Do not use malathion on African violets or canaert 

 red cedar. Do not use diazinon on ferns or hibiscus plants . 



Galls , or wart-like growths, appear on many species of trees at this time of the 

 year. These warty-looking growths usually develop on the leaves. They rarely cause 

 any damage to branches of the trees, other than that of disfiguration. Some galls 

 are caused by wasps, jumping plant lice, mites, and midges. The abnormal growth of 

 plant tissue results from a stimulation by one of these pests, causing the tissue to 

 develop around them, When galls can be observed on leaves, it is generally too late 

 for control. (See Bulletin No. 5 for suggestions on control) 



Lace bugs are appearing on sycamore trees- -which in many areas are already having 

 their problems with sycamore anthracnose. They are small, usually whitish insects 

 and can be recognized by the sculptured lace-like pattern on the upper surface of 

 the body. This pattern is found only in adults; the nymphs are usually spiny. Their 

 feeding on the underside of leaves causes a yellow spotting of the leaf and with con- 

 tinued feeding the leaf becomes brown and falls off. If control is necessary, apply 

 sprays of carbaryl (Sevin) or malathion. 



SPECIAL NOTE TO EXTENSION ADVISERS ON CICADAS 



Dr. L.J. Stannard, Entomologist and Taxonomist with the Illinois Natural History Sur- 

 vey, would like to obtain specimens of nymphal skins and adult periodical cicadas 

 from northern Illinois. Please send these to: Dr. L.J. Stannard, 285 Natural Resources 

 Building, Illinois Natural History Survey, Urbana, Illinois 61801. Please include the 

 location (county and town) where the specimens were collected. 



PLANT DISEASES 



WHEAT DISEASES 



Septoria leaf blotch and root rots are the diseases primarily responsible for thin, 

 weak wheat stands throughout the state. As a result of the unusually cool, wet weather 

 that prevailed all spring, Septoria can now be found even on the flag leaves of grow- 

 ing wheat. This is one of the worst years in history for this disease. 



Septoria glume blotch , caused by a closely related fungus, is now attacking glumes, 

 causing a dark, purple-brown discoloration. As this disease advances, small, black 

 specks (fungus -fruiting bodies) develop in the infected area. 



Scab is the most important wheat disease to watch for now. Look for prematurely 

 bleached heads that are empty or contain shriveled kernels . Pinkish-orange mold may 

 also develop, especially at the bases of the glumes. Later, look for black specks 



