-4- 



susceptible varieties (primarily Arthur), prior to the suggested "fly-free" date. 

 These factors, plus weather conditions favorable to high survival of the fly and 

 a partial second generation were responsible for a sudden buildup in numbers and 

 subsequent injury to wheat. 



Many fields damaged last fall by the fly have recovered to a considerable extent. 

 However, a large number of "flaxseeds," the puparium or overwintering stage of the 

 Hessian fly, have been found in these fields. During the next few weeks, the 

 spring generation of the fly will emerge and deposit tiny eggs in the grooves on 

 the upper sides of the wheat leaves. These eggs have the appearance of a string 

 of wieners. 



Newly hatched larvae, which are reddish and later turn white, can be found just 

 above the point where the leaf sheath joins the stem. The maggots feed by rasping 

 on the straw; but they never enter the stem, as do some other insects. Yields of 

 susceptible varieties may be reduced by the feeding activity of the maggot. Plants 

 may break over before harvest at the point where the stem was weakened by the 

 larval feeding. 



There are no chemical control methods available to prevent damage by Hessian flies 

 this spring. 



LIVESTOCK INSECTS 



Face flies . Low in numbers were observed for the first time this week on pastured 

 cattle. Those near wooded areas had the worst problem, but still only averaged 

 two flies per animal. Since face flies are just coming out of hibernation, the 

 number per animal will probably increase by 10 to 30 within the next week to ten 

 days if the weather is warm. 



Although the face fly populations during the last three years have been on the in- 

 crease, it is still too early to make predictions for this summer. 



Apply Ciodrin for control at this time, in order to prevent these overwintering 

 adults from laying eggs and producing the first generation this year. 



WEED CONTROL 



INCORPORATION EQUIPMENT 



The adequacy of herbicide incorporation depends on the type of equipment used, 

 plus such factors as speed, setting, physical condition of the soil, soil moisture, 

 and atmospheric conditions. Under similar conditions, a disk may do a little better 

 job of incorporation than a field cultivator. But the cultivator may be adequate, 

 especially if it is of the shovel type and if a harrow is pulled behind, the units 

 are moved fast enough to create a good mixing action, and the operator does not 

 skimp on the herbicide rate. 



The main purpose of the first incorporation is to cover the herbicide and to pro- 

 tect it from surface loss. Check to see that this job is being done. Let someone 

 else drive the tractor so you can walk behind and watch the soil action, to be sure 

 you are getting good mixing action and coverage. There is no big rush for the 

 second incorporation. It is mainly to give a more-uniform distribution, avoiding 

 "hot spots" and skipped-over areas. Some research at the University of Illinois 

 suggests that two trips in the same direction may produce about the same results as 

 cross -disking. 



