Tar Spot
A new report details the need for more ag funding to address existing weeds, insects and diseases as well as agronomic problems that have yet to reach U.S. shores.
The disease is causing turmoil for farmers who have a large crop in the making. In some cases, a Hail Mary fungicide application at R4 up to early dent (R5) might make sense this season, say agronomists.
On the heels of Crop Tour, Pro Farmer projects corn yields at 6.1 bu. below USDA’s August estimate, while soybean yield numbers are nearly aligned.
Iowa could be the nation’s top state this year for corn and soybeans, but both crops are in a race to beat disease pressure that’s gaining momentum. Illinois corn continues to ride the struggle bus, while the soybean crop there is positioned to deliver high yields.
There is still up to 55% of the kernel dry weight left to be accumulated by many corn hybrids at this point — starch that can contribute significantly to grain fill and higher test weights.
Got tar spot? Economic data shows two passes can offer ROI, depending on the hybrid. However, if your crop got dinged at pollination that’s a different scenario and might require a revised game plan that takes yield estimates into consideration.
Farmers and aerial applicators tell Randy Dowdy and David Hula some of the key considerations for effective fungicide applications are timing, droplet size and product reach in the crop canopy.
Unlike most leaf diseases, tar spot starts impacting the crop at the bottom of plants. That means fungicides you apply must penetrate and get deep into the crop canopy to provide effective treatment. If you opt to not treat the disease, consider making plans to harvest early and pre-booking some dryer gas.
Now’s the time to be scouting for the disease, especially where the inoculum is present. Tracking weather data, particularly daily humidity levels, can help you keep an eye on tar spot this season.
Corteva Forcivo will feature three modes of action to address foliar diseases in corn, soybeans, wheat and other crops via overlapping preventive and curative activity.
Despite being outside the optimum window for tar spot control, this Wisconsin field trial yielded strong results.
Iowa farmers say a foliar fungicide application can add more bushels per acre by preventing losses to disease pressure and minimizing the impact of environmental factors, such as heat stress and drought.
Scientists from the Agricultural Research Service have identified several different species of fungi and bacteria that can stop tar spot from developing.
There’s a big crop in the field for many Midwest growers, and it requires fuel. N supplies ears with the energy they need to add kernels all the way to their tips and to pack on weight.
If you have tar spot, Southern rust or other disease pressure and plan to dry the crop in the field, you might want to spray again.
When average daily humidity levels reach and stay at 75% or above, that’s a signal your crop could be at high risk from the disease.
Some growers are struggling with waterlogged fields that are producing stunted, yellowing corn. Field Agronomist Ken Ferrie offers farmers hope and help with his practical, no-nonsense recommendations.
Ken Ferrie outlines various treatment scenarios, depending on what farmers find in their fields. He cautions that severe infections can easily cause 60-bu.-per-acre yield losses.