-5- 



This problem is not a common one in Illinois , but it has occurred in research fields 

 and occasionally in farmers' fields. We know it can occur. The best way to avoid 

 it is to heed the 2,4-D label directions, being careful not to spray from the tassel 

 to the dough stage. 



GARDEN WEED CONTROL 



Symptoms of 2,4-D injury may show up on some garden crops at this time of the year. 

 The inj ury may appear as a crinkling or "puckering" of the leaves and as parallel 

 vernation- -the veins of the leaf tend to run parallel to each other and in the same 

 direction as the midrib. 



An extremely small amount of 2,4-D moving into a garden may be enough to produce these 

 symptoms. Although 2,4-D is not considered a highly toxic herbicide, the psychologi- 

 cal effects on people who have eaten produce from an affected garden can be real- -even 

 if no actual danger to health exists. In some cases, 2,4-D may be blamed for an en- 

 tirely unrelated illness. 



To be on the safe side, it is best NOT to recommend eating any garden produce that has 

 been contacted by a herbicide- -unless the herbicide is registered for use on that spe- 

 cific crop and a tolerance has been set. 



PLANT DISEASES 



SMALL-GRAIN DISEASES 



Crown rust- -or leaf rust- -of oats is now showing up, especially in northern Illinois. 

 Small, scattered, oval -to -oblong, orange -yellow pustules develop primarily on oat 

 leaves, but may also occur on the leaf sheaths, stems (culms), and panicles. The pus- 

 tules soon break open to release a dusty mass of golden-colored summer spores. 



The number and size of the pustules vary greatly, depending on the susceptibility of 

 the oat variety and the severity of the infection. If the weather favors infection 

 (high humidity, fogs, frequent heavy dews or light rain, and temperature about 70° F.), 

 the pustules become numerous and may run together as the season progresses. A new 

 generation of summer spores may be produced every seven to fourteen days. These spores, 

 in turn, are blown by air currents, spreading the disease from plant to plant and from 

 field to field during the remainder of the growing season. 



As the oats mature, black overwintering spores are formed. These spores may also de- 

 velop during periods of adverse weather- -for example, during periods of extreme drought, 

 excessive moisture, or very high temperatures. 



The most effective control measure is to grow varieties that are resistant to crown 

 rust, that mature early, and that are adapted to your area. Early maturing varieties 

 often escape moderate to severe rust damage. Planting as early as possible in the 

 spring also helps the crop escape the rust. Whenever possible, eradicate rust- 

 spreading buckthorn growing within a mile of oat fields. 



For more information on this disease, see Report on Plant Diseases No. 109, available 

 from the Department of Plant Pathology, 218 Mumford Hall, Urbana, Illinois 61801. 



READ THE LABEL AND FOLLOW ALL PRECAUTIONS 



This weekly report was prepared as follows: 



INSECTS: H.B. Petty, Steve Moore, Roscoe Randell , Don Kuhlman , and Tim Cooley , College 

 of Agriculture, University of Illinois at Urbana-Champaign , and the Illinois Natural 

 History Survey. 



