Integrated Crop Management News
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November 20, 2023Authors
Each year, Iowa State University prepares a list of soybean varieties available in Iowa that are resistant to the soybean cyst nematode (SCN). The list was updated in October 2023 and the publication is now available online. There are 48 more varieties in the 2023 list than in 2022 including 40 more with Peking SCN resistance. Varieties with Peking resistance are highly useful for managing SCN because they limit reproduction of most Iowa SCN populations and protect against yield loss more effectively than varieties with the common PI 88788 resistance.
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November 10, 2023Authors
The soybean cyst nematode (SCN) is estimated to cost soybean producers $1.5 billion annually in North America. A new online resource called the SCN Profit Checker, from the SCN Coalition, uses data collected from Iowa State University research to estimate percent yield loss from SCN and the cost of yield reductions in dollars lost in individual farmer fields. This article explains more about this resource, where to access it and how to use it.
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November 6, 2023Authors
The soybean cyst nematode (SCN) is the most damaging pathogen of soybeans in Iowa and the entire US, costing producers $1.5 billion annually. The pathogen warrants more attention and effort to detect and manage than often is given. It is easily detected and quantified from soil samples. An optimum time to collect soil samples from fields is immediately after corn and soybean harvest are complete. This article explains why and how to collect and submit soil samples for SCN testing.
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October 9, 2023Authors
Harvest has taken off in recent weeks as crops are quickly drying down. The open fields are tempting manure applicators to get started on their manure applications; however, it is worthwhile to pause and consider the fertilizer value that is given up when manure is applied to warm soils.
What is the value and cost of manure?
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September 28, 2023Authors
With yet another sighting of Asian copperleaf (Acalypha australis) this fall, it’s a good reminder to keep an eye out for this new species during harvest. Asian copperleaf (Acalypha australis) was first discovered in Iowa in 2016 in a corn field near Cedar Falls. Prior to this discovery, the only documented infestation in North America was within New York City.
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September 25, 2023Authors
Across Iowa, grain harvest is ramping up. A challenge this harvest season will be dealing with variable grain moistures from field to field as well as within individual fields. Additionally, drought conditions that have persisted all year and rapid accumulation of growing degree days are leading to grain that quickly became overly dry. Follow the below set of tips to limit yield loss this fall.
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September 15, 2023Authors
Decisions for phosphorus (P) and potassium (K) fertilization should consider slightly lower but still fluctuating crop and fertilizer prices compared with last year and very variable rainfall across the state. The current or expected crop and fertilizer prices after harvest and the yield level this harvest have a major impact on producers' fertilization decisions.
Soil-test P and K interpretations were updated last winter
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September 5, 2023Authors
While the registration of 2,4-D and dicamba products for over-the-top use in resistant-varieties has improved waterhemp control for many farmers, weed scientists warned that these herbicides would eventually select for resistant waterhemp populations. Bayer recently reported the discovery of two likely dicamba-resistant waterhemp populations in Iowa, which warrants a discussion on best management practices to slow the evolution of resistant waterhemp populations.
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August 16, 2023Authors
This is a great time of year to scout for Palmer amaranth (Amaranthus palmeri) in Iowa crop fields. While Palmer amaranth has been identified in more than half of Iowa’s counties, new identifications have slowed since the widespread introductions on non-crop acres in 2016.
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August 7, 2023Authors
Since 2010, aphids have been colonizing corn later in the summer and can build up to surprising levels in Iowa. They can be found at the base of the stalk, around the ear and sometimes above the ear leaf. Aphids have been sighted in corn again this summer.
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August 7, 2023Authors
Soybean aphids have been quiet the last few growing seasons in Iowa. This year there have been isolated fields in northern counties that exceeded the economic threshold, but most fields have not warranted insecticides. However, many scouting reports and our observations in northern Iowa counties for the last two weeks show soybean aphids are established. We strongly encourage sampling soybean now to gauge the pressure and make timely treatment decisions.
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August 4, 2023Authors
The Ag Container Recycling Council (ACRC) works with private and state contractors across the United States to collect and recycle 55-gallon or smaller containers. In 2022, over 900,000 pounds of pesticide containers were collected and recycled in Iowa.
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July 12, 2023Authors
When it comes to soybean, one of the most common types of injury is defoliation from insects. This damage can be easily detected in the canopy by observing holes in the leaves or along leaf margins as insects with chewing mouthparts consume leaf tissue. The insects most responsible for defoliation are bean leaf beetles, Japanese beetles, and grasshoppers.
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June 26, 2023Authors
Corn rootworm egg hatch in Iowa typically occurs from late May to the middle of June, with an average peak hatching date of June 6 in central Iowa. Development is driven by soil temperature and measured by growing degree days (GDDs). Research suggests about 50% of egg hatch occurs between 684-767 accumulated GDDs (since January 1; base 52°F, soil).
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June 16, 2023Authors
Japanese beetle development seems to be a bit ahead of schedule this year, much like other pests we track each spring. Japanese beetle adults begin emergence when approximately 1,030 growing degree days (GDD; base 50°F) have accumulated since January 1 and will continue emerging until 2,150 GDD have accumulated. Japanese beetle adults likely began emerging in the southern portion of the state last week, and emergence will likely occur within the next two weeks in northern Iowa (Figure 1).
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June 16, 2023Authors
Plant-parasitic nematodes that feed on corn are relatively common in Iowa, but their presence in fields does not mean that damage and yield loss are occurring. The number of nematodes necessary to damage corn varies greatly among different nematode species, and the potential for yield loss can only be assessed by determining the types and numbers of nematodes present in a field. This article explains how to sample corn fields to determine if nematodes are causing damage and likely to reduce corn yields. Management options for nematodes on corn also are listed in the article.
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June 12, 2023Authors
Variable rainfall and soil temperatures across Iowa since April have resulted in variable planting dates and early crop growth. As of today, June 12, upper soil moisture ranges from deficient to about normal. Some producers and consultants are wondering if the dry conditions are affecting the normal crop uptake of soil nutrients and plant tissue-test results.
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June 12, 2023Authors
Most soybean producers in Iowa have heard of the soybean cyst nematode (SCN) and are aware it is considered the most yield-reducing soybean pathogen in Iowa. Adult females of SCN can be seen on infected soybean roots with the unaided eye and they now are present on soybean roots. Read more in this article about digging roots to check for SCN.
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June 8, 2023Authors
Two male adult soybean gall midges were found in emergence cages at the Northwest Research and Demonstration Farm near Sutherland on June 6. This is about one week earlier than previous first captures in Iowa since we started monitoring emergence in 2019. The first Midwest report of soybean gall midge emergence in 2023 was May 31 near Mead, Nebraska. You can keep up with soybean gall midge emergence at soybeangallmidge.org/.
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June 6, 2023Authors
Stalk borer is an occasional pest of corn, but it can be persistent in some fields, especially those fields near perennial grasses that serve as overwintering sites (fence rows, terraces, and waterways are typical sources). Tracking degree days is a useful way to estimate when common stalk borer larvae begin moving into cornfields from their overwintering hosts. Foliar insecticide applications are only effective when larvae are migrating and exposed to the insecticide.