Rust could prevent big yields in US corn crop

The US corn crop has all the potential to be a big one, but Southern Rust is creeping its way up the crop and the question now is if the crop can fill out before the disease takes over. One agronomist on the tour said that he has never seen rust like it in 36 years.

Key to the potential big yields this year have been the earlier planting dates and rainfall levels.

The Irish Farmers Journal travelled to the US this week to take part in the Pro Farmer Crop Tour and saw the big yields in the field, as well as the wet land. Mucky boots were the order of the week and irrigators were turned off in many fields this year as soil moisture levels were more than satisfactory.

Crops were impressive and look like they could yield very highly, with yield predictions of over 200bu/ac in many cases, but there are still a number of weeks to go until harvest and crops have a long way to go.

Southern rust, similar to yellow rust that we see in wheat in Ireland, has affected many crops in Iowa, one of the biggest states for corn. Scouts on the tour also reported tar spot in parts of Iowa.

A second fungicide application was being recommended to growers to get that rust under control.

Randy Dowdy, a farmer known for breaking the world record for soybean yields, in the south east of the US, said farmers can’t afford to not apply that second fungicide. He has seen 60 bu/ac declines in crop yields as a result of Southern rust where crops were sprayed and not sprayed.

Emily Carolan, who crunches the numbers on the tour said that she doesn’t think a fungicide application would help some of the crops at this stage as the disease has progressed so much. Looking in with the Irish Farmers Journal’s eyes this statement is reasonable as rust levels in my opinion are very high in some crops and in some cases out of control, but a fungicide may still help where rust levels are low.

Southern rust was visible in all states on the crop tour, but was worse in some crops. Travelling in Minnesota on Thursday the Irish Farmers Journal saw less in the crops visited compared to Iowa crops on Wednesday.