Author: Brandy VanDeWalle

Things to do while in the combine

With harvest in full swing, many farmers are probably reflecting on the season, but might not be taking notes for next year. This is the time to start planning for next year’s crops.  While in the combine, look for weed and insect problems to fix for next year. Harvest provides an opportunity for a final evaluation of your weed management program and to a lesser extent, your insect management program. As you travel over all of your fields, take a minute to record observations such as where weeds are present.  Be sure to note the exact locations and details so you know how to correct it for next year.

The next step of being a “crop scene investigator” is to make the linkages and relate weed or insect problems with management decisions that were made.  Use your yield monitor to help you adjust your problem areas. 

Former UNL Weeds Specialist, Alex Martin once provided the following on weed management: Small grass and broadleaf weeds are likely to have developed after the first month of the growing season, perhaps after a POST treatment or cultivation or after a PRE treatment has become ineffective. These smaller, late developing weeds may produce seed and perpetuate the problem but are unlikely to have impacted yield. These late developing weeds are most likely in areas where the crop canopy developed more slowly, allowing penetration of the light necessary for weed establishment. Large weeds present at harvest likely are escapes which were not controlled by your primary weed management program. Depending on the number of these weeds, a change may be indicated for your weed management program. 

You may be able to see indications of herbicide resistance at harvest although the picture would have been clearer with an earlier examination. Herbicide resistance is first evident as a limited number of escapes in the field. There are many causes of weed escapes other than herbicide resistance. The key is to look for scattered large plants or small patches that were not controlled by your primary program. Dead weeds adjacent to the large ones provide even more evidence that resistance may be present. These fields should be monitored closely the next year.

Weed patches indicate that your weed management program is not uniformly effective across the field. There may be several causes, however the effect is the same – these field areas will have higher concentrations of weed seed as compared to the rest of the field. This means the problem next year will be most serious in these patches. If you continue to manage the field as in the past, the patches will persist or become larger. A change in management is needed to prevent “growing” these weed patches.

Finally, perennial weeds typically occur in patches and many are less susceptible than annuals to most weed management programs. Perennials usually call for special attention not warranted on the entire field. Identifying problem areas in the fall can make it easier to target them in the spring.

With a little extra effort at harvest you can gather information that will be useful in developing next year’s weed management program.

Control Thistles during October

As a kid growing up on the farm, my sister and I were always responsible for controlling the thistles in our pastures and on the farm which usually meant picking the heads off of them and using a shovel to dig the plant out.  Along with hauling irrigation pipe, it was not the most enjoyable job on the farm, but it did teach us hard work and responsibility.  If you have thistles and don’t enjoy digging them, now is actually the time to control them with herbicides.

If you walk out to the usual patches, I’ll bet you find many thistle seedlings.  Most thistle seedlings this fall will be small, in a flat, rosette growth form, and they are very sensitive now to certain herbicides.  So spray this fall and thistles will not be a big problem next year.

Bruce Anderson, UNL Forage Specialist offers some great information on controlling thistles this fall. Several herbicides are effective and recommended for thistle control.  Maybe the most effective is a newer herbicide called Milestone, or a combination of Milestone and 2,4-D called Forefront.  Two other very effective herbicides are Tordon 22K and Grazon.  But be careful with Tordon and Grazon since they also can kill woody plants, including trees you might want to keep.  2,4-D also works well while it’s warm, but you will get better thistle control by using a little less 2,4-D and adding a small amount of Banvel or dicamba to the mix.   

Other herbicides also help control thistles in pastures – like Redeem, Cimarron, and Curtail.  No matter which weed killer you use, though, be sure to read and follow label instructions, and be sure to spray on time.

Next year, avoid overgrazing your pastures so your grass stands get thicker and compete with any new thistle seedlings.  Give some thought now to thistle control during October and November.  Your pastures can be cleaner next spring.

 Evergreens turning brown?

If you have noticed that some of your coniferous trees have started to turn brown and have been loosing needles, more than likely your trees are going through a normal phase of their life cycle called fall needle drop.  This can cause concern for homeowners when they see their evergreen trees turn brown, but realize that  the older needles on the inside of evergreen trees are shed each fall after they turn yellow, brown or reddish tan in color.  Some years the process is very subtle and therefore not noticed, especially when it is on the inside part of the tree.  Pine trees can hold their needles for 2-5 or more years, depending on the species. Spruce trees generally hold onto their needles longer than pine trees do, approximately 5-7 years.

Fall needle drop is a natural condition and is not a sign of disease or insect infestation; however, any factor that increases stress on evergreen trees will intensify the autumn needle drop. Stress factors include drought, herbicide injury, root damage and insect or disease damage.