Nutsedge overwinters primarily as tubers (nutlets) that sprout in the spring and 

 form rhizomes. A coronal node forms on the rhizome about 1 to 1-1/2 inches below 

 the soil surface. From this crown area roots, shoots, and new rhizomes form. The 

 rhizomes produce plants at first, but later in the season they tum down and develop 

 new tubers for overwintering. 



The crown area that develops below the surface of the soil is a critical area for 

 yellow nutsedge control. The most -effective control program involves a combination 

 of preplant tillage, an incorporated herbicide, and postplant tillage. Nutsedge is 

 usually found in low- lying, wet areas. It usually emerges about the corn-planting 

 time or when the sprouts come up. 



Controlling nutsedge in soybeans is generally easier than in corn, because soybeans 

 are planted later. This gives the farmer time to locate isolated areas of nutsedge 

 infestation, use preplant tillage, and broadcast a herbicide just on those areas. 

 The two herbicides that have proven useful for nutsedge control in soybeans are 

 alachlor (Lasso) and vernolate (Vernam) . Both should be used at the highest rec- 

 ommended rate, and should be incorporated. This can be combined with preplant 

 tillage. 



The herbicides used for nutsedge control in corn are alachlor (Lasso) , butylate 

 (Sutan) , and atrazine (AAtrex) . EPTC (Eptam) has provided adequate control, but 

 the corn tolerance has not been sufficient. The best treatments in research trials 

 on corn have been either butylate (4 pounds per acre) or alachlor (5 to 4 pounds 

 per acre) --applied preplant, incorporated, and followed by an early postemergence 

 treatment of atrazine (2 pounds per acre) plus nonphyto toxic oil (1 gallon per acre). 



CHECK WEEDY SPOTS 



It pays to check fields for weedy spots during the spring. Giant ragweed is now 

 germinating, and smartweed will soon start. These are two of the first field 

 problems with weeds. Giant foxtail and pigweed will start germinating in about 

 one to two weeks, depending on the temperature. I 



If you find areas of high infestation, it might be worthwhile to consider broad- 

 casting a herbicide on these potential trouble sports. Such areas are often found 

 along drainageways , turn- rows, headlands, and fence lines --places where it is most 

 difficult to cultivate. Use a band application of herbicide on these areas. Cul- 

 tivate the rest of the field. 



TANK-MIXING HINTS 



Many herbicides are being applied with liquid fertilizers. Problems of compatability 

 sometimes arise when emulsifiable concentrates are mixed with liquid fertilizers be- 

 cause the emulsifier is not salt-stable. Some manufacturers have special pesticide 

 formulations for liquid-fertilizer application. Others specify that the emulsion 

 stability must be checked and if needed, that a compatability agent such as Compex 

 or Sponto/68 be added. 



Check compatability in quart jars before mixing an entire tankful . First, deter- 

 mine the volume of spray per acre. With liquid fertilizers, this will depend on 

 the analysis used and the rate desired. Next, determine the volume or weight of 

 the pesticide to be applied per acre. Then, convert the number of quarts or pounds 

 of additives and gallons of spray carrier to the amount per pint of spray. 



