Crop Update from Aurora, NE
Mild winter and warm spring was to bring on more insect issues.
We had the lowest amount of first generation corn borer larvae in recent memory. I have quite a bit of non-Bt yellow and white corn that normally requires some fields to be treated.
Corn blotch leaf miners are trending to be much lower than last year. Very few western bean cutworms have been found.
There are few bean leaf beetles on soybeans, although most fields got an insecticide treatment on the seed. Japanese beetles are on their usual local isolated fields so far.
The continuous corn fields that I check have had very little rootworm feeding. But almost all had full rates of bifenthrin with fungicide soon after tassel the past 2-3 years. I know bifenthrin isn’t the best on controlling rootworm beetles, but egg laying does seem to be reduced. Most of my continuous corn is non rootworm Bt and we used a liquid insecticide in furrow with 10-34-0. I have heard of many fields with very high rootworm beetles numbers that had to be controlled to prevent silk clipping.
Gray leaf spot and common leaf rust are at low levels on corn with the much drier conditions so far this year. However, the dreaded southern rust has been appearing on some lower corn leaves in the past 7-10 days. Most of the field corn, popcorn and white corn have received a fungicide along with an insecticide aerial application soon after tasseling. This has helped greatly on plant health in previous years and controlling to some degree rootworm beetles, stink bugs, leaf miners and good residual corn borer control.
If one is not a firm believer in early preplant burndown/residual weed control on both corn and soybeans, I’m not sure what it will take to change the grower’s mind after this spring. Continued lower yields will be their result and bringing on resistant weeds for the rest of us to deal with in the future.
Observing soybeans fields in the area, many growers allowed volunteer corn plants to get 3-4 feet tall to control with one application. This has resulted in poorer control and in some cases many partial escapes.
The uncontrolled volunteer corn does make good territory marking posts for the dickcissel birds.
The importance of some early irrigation management allowed for a better nodal root system to be developed on the corn. Letting the top 12 inches to get very dry before some rain finally fell at the V10-11 stage, had the developing nodal roots not forming properly and plants leaning in the field from the dry winds. One pass with the pivots made a big difference. Roots are well into the 3rd and 4th foot now on the silt loam soils with blister to milk stage corn.
Drought is taking a big toll on non-irrigated areas. A big difference is seen on various tillage practices and whether weeds were controlled early before drying out the ground. Strip-till non-irrigated has more heavily stressed corn and soybeans than no-till or even ridge-till.
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