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NSECT WEED & PLANT DISEASE SURVEY BULLETIN 



TATE/COUNTY/LOCAL GROUPS/US. DEPARTMENT OF AGRICULTURE COOPERATING 



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FOR IMMEDIATE RELEASE 



No. 14, June 22, 1973 



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 determine local conditions. 



INSECTS 



FORAGE INSECTS 



Alfalfa weevil damage is decreasing rapidly. Most of the larvae have pupated and 

 the adults are emerging from the pupae. The adults are feeding on the leaves, but 

 this is slowing down. These adults soon will go into their summer hibernation 

 stage, and will not become active again until the weather turns cooler this fall. 



Alfalfa producers in the southern half of Illinois who had trouble with alfalfa 

 weevil this spring should plan now to apply an insecticide to their fields in ear- 

 ly November. The adult weevils will have migrated back into the alfalfa fields by 

 then and can be killed before they deposit their eggs. 



Potato leafhoppers are also pests of alfalfa. These tiny, green, wedge-shaped in- 

 sects run sideways when disturbed. They feed by sucking sap from the plant and in- 

 ject a toxin as they do so. Damaged alfalfa plants turn yellow to purple and are 

 severely stunted. When this occurs, cut the field; the new growth should be all 

 right. If populations of leafhoppers are very high, however , an application of 1 

 pound of malathion or 1/2 pound of methoxychlor will provide good control. There 

 is no waiting period between the application of malathion and harvest, but there is 

 a week's waiting period for methoxychlor. 



SMALL GRAINS 



Stored- grain insects can be a problem if wheat is to be stored; clean up and 

 sweep out the storage bins and the area around the bins before putting in new grain. 

 (See Bulletin No. 12, June 8,1973, for details about spraying the bin and the grain.) 



CORN INSECTS 



Corn leaf aphids could be a problem on late corn. Plan now to examine these fields 

 at regular intervals in late July and early August. 



Corn blotch leaf miners will soon appear on corn leaves. The white trails that ap- 

 pear on the leaves are made by dirty yellow maggots burrowing between the upper and 

 lower surfaces of the leaves. When these maggots are abundant, the leaves appear to 

 have alternate green and white stripes . They are not thought to be economically im- 

 portant, but many people become quite concerned when they see the damage. 



