When the combines are about ready to roll, or are getting started, there are usually three big issues we think about: How are yields doing, how is our equipment holding up, and what is the weather forecast?
It's been a pretty challenging summer, with most of the state fighting serious drought, storm damage in many areas, and some regions even dealing with excess moisture.
With spring fieldwork starting in some areas, we'll be going full speed with fertilizer and herbicide applications over the next few weeks if the weather cooperates. Hopefully, planters will start to roll on time as well, and before we know it, we'll be ready to scout emerged crops.
It's challenging to think about soybean populations when it's below zero outside in mid-February. Heck, I don't even like to think about our seed sitting in storage in temperatures like this. But the other day, a seed dealer and I were talking about various soybean topics, and he reminded me that we may be in the field a couple months from now.
If there was ever a vote on a year that folks would like to get a “do over” on, 2020 would be a leading candidate. Since we can’t vote 2020 away, we keep grinding away at it a day at a time. And it won’t be too much longer before it will be time to start soybean harvest.
An article I wrote a month or so ago hit on a lot of pests to watch for in soybeans, focusing on the more common ones. At the time, we were in pretty solid shape in terms of soil moisture, so we didn’t spend much time on pests that can hit when hot summer temps combine with dry weather. With that dynamic changing in much of the state, it’s time to share a “heads up” on some sporadic pests on the rise this season.
With 2020 being an election year, the ads will be relentless, so we’ll probably all need a break from TV, radio and social media occasionally. There are likely other more exciting (or more relaxing) things to do or places to be, but scouting soybean fields has a lot to offer! Scouting to find issues early and taking action when needed is still the best method for a lot of our pest issues.
What might seem like a pretty simple question can be a pretty loaded one, too. This time of year, some version of “Should we treat our soybean seed, and if so, with what?” comes up fairly often. Sometimes the answers are short and sweet, but more often, the question turns into a discussion. The nearly infinite combinations of field conditions, management decisions, weather, seed genetics and many other factors make the seed treatment decision too dynamic for a simple yes or no.
Over the years, continued planting of soybean varieties with PI 88788 resistance has caused soybean cyst nematode to develop resistance to SCN-resistant soybean varieties. There are hundreds of SCN resistant varieties available, but almost all of them have resistance genes from the PI 88788 breeding line. Fewer than 5% of SCN-resistant soybean varieties available for farmers to plant have the alternative source of resistance named Peking.
In last month’s column, we discussed ways to fine-tune your soybean seed selection for 2020 planting. One of the steps mentioned was matching soybean agronomic traits to your particular soils and production systems. One of these traits, a very important one, is variety resistance to soybean cyst nematode. SCN is found in about 75% of Iowa soybean fields.
We’re getting to the end of another challenging crop year, but that doesn’t mean the work lets up much. On top of wrapping up harvest, fall anhydrous application and fieldwork, it’s also time to start other 2020 crop planning. With prepay season coming up fast, let’s talk about fine-tuning soybean seed selection for next year.
This analogy might seem like a stretch, but hang in there: Think of crop nutrients and lime like a football offense. In a high-powered offense, your quarterback, running backs and receivers typically make the highlight reels with exciting plays. In most cases, a successful offense starts with solid blocking from the line. Good line play doesn’t always get the credit it deserves; unless you are really watching, it may go unnoticed. But without it, an otherwise high-powered offense generally struggles.
While we typically think of potassium deficiency as showing up in the lower crop canopy, it often shows on the upper leaves late in the season. We saw late-season potassium deficiency in some fields this year and last.
Some plants may have interveinal chlorosis (yellowing) and necrosis (death) on leaves in the upper canopy. There are a number of potential causes, and an article from the Crop Protection Network does a nice job of outlining the causes and how they differ.
Farmers have seen several soybean insects show up in fields this summer in Iowa. These pests include thistle caterpillars, soybean aphids and soybean gall midge.
Soybean fields have been invaded by unusually high populations of thistle caterpillars, which defoliate soybean leaves. It is recommended that soybean growers apply a foliar insecticide if damage exceeds 20% per plant after plants reach reproductive stage. If you have caterpillar feeding damage before bean plants are in reproductive growth stage, the treatment threshold is 30% defoliation per plant.
With the extremely wet spring and delayed planting this year, a significant percentage of Iowa’s soybean crop was planted in June. According to USDA’s weekly survey, 70% of Iowa’s 2019 soybean crop was in the ground as of June 9, leaving 30% to be planted later. The survey for the week ending June 16 showed 11% of the expected bean acreage yet to be planted.
Looking at their fields this summer, many farmers are wondering: Will my late-planted beans reach maturity before the first killing frost hits this fall?
The old saying “honesty is the best policy” is often attributed to Benjamin Franklin and is sound advice. But he probably never had a bunch of soybean farmers — that had already been through the wringer — wondering what the next kick in pants from Mother Nature would be.
So, when I’m trying to figure out how to talk about challenges these later-planted beans may face, it’s tempting to sugarcoat it a little. Leave it to Mark Twain to bail me out with his wisdom: “Honesty is the best policy, when there is money on it.”
