Integrated Crop Management News
-
July 14, 2021Authors
Cornfields are starting to tassle and silk all over Iowa. Many insects like to feed on silks, so it is a critical time to assess pollination rates. This article highlights a few of the most common silk feeders of importance.
-
July 13, 2021Authors
In the last decade, cover crops have grown in both interest and acres, yet there is still room for more adoption across Iowa and the region. It is obvious that cover crops require more management though and with that management there will undoubtedly be challenges. In just a few weeks the cycle for cover crop establishment, growth and termination will begin.
-
July 13, 2021Authors
Rainfall has been extremely variable this season in Iowa. There has been severe drought in many areas of Iowa. In contrast, rainfall has been excessive in some areas of southeast and southern Iowa. Soybean with poor growth with pale green or yellowish color has been observed in low-laying fields or field depressions with poor drainage and frequent waterlogged soils since May.
-
July 9, 2021Authors
Corn tassels began showing in some Iowa fields this past week and in the next week corn in most fields will be at the R1 stage (silking). Most soybean fields are at R2 or will be at the R2 to R3 growth stage soon. Nutrient concentrations vary greatly with crop growth stage and plant part sampled.
-
June 17, 2021Authors
This week, the first adult soybean gall midges (Photo 1) were collected in Iowa and Minnesota. Thanks to Lauren Schwarck (Corteva Agriscience) for monitoring several emergence traps this year. The positive detections were located in Buena Vista County, an area with persistent soybean gall midge populations since at least 2017.
-
June 14, 2021Authors
Corn rootworm egg hatch in Iowa occurs from late May to the middle of June, with an average peak hatching date of June 6 in central Iowa. Even with recent warm temperatures, hatching is a bit delayed this year due to cool spring temperatures. 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).
-
June 11, 2021Authors
The soybean cyst nematode (SCN) is the most damaging pathogen of soybeans in the United States. Farmers in Iowa successfully managed SCN for many years by growing SCN-resistant soybeans in rotation with corn. However, almost all resistant varieties contain SCN resistance genes from the same breeding line, named PI 88788. Not surprisingly, SCN populations in fields throughout the state are overcoming the PI 88788 resistance because of use of those resistance genes for more than 30 years.
-
June 11, 2021Authors
Iowa State University (ISU) Extension and Outreach field agronomists have been receiving phone calls and texts about striped corn leaves this past week. There are many reasons for striped corn, and the cause of light green, whitish, or yellowish stripes sometimes is not obvious. Here is a review of some of the reasons for striped corn and also methods to distinguish what might be causing the stripes.
Genetic Striping
-
June 11, 2021Authors
This spring, we have had several reports of fields with high numbers of grubs from field agronomists in central Iowa. There are multiple species of white grubs in Iowa, including the Japanese beetle. Recent warm temperatures are accelerating insect development, and with forecasted temperatures, Japanese beetle emergence could begin in southern Iowa counties this week (Figure 1).
-
June 8, 2021Authors
Stalk borer is an occasional pest of corn, but it can be persistent in some fields, especially those fields near fence rows, terraces, and waterways that serve as overwintering sites. Tracking degree days is a useful tool 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.
-
June 8, 2021Authors
ISU Extension and Outreach Field Agronomists recently highlighted a significant number of phone calls related to fomesafen carryover injury to corn rotated from 2020 soybeans.
-
June 2, 2021Authors
“How much nitrogen (N) has been lost?” is a question we get this time of year, particularly in areas that have received more rainfall. Although most of the state is dry, the southeast part of the state has received above normal rainfall, and there are valid concerns that some N has been lost and additional N could be needed.
-
May 28, 2021Authors
Canada thistle has been a consistent threat to crop production and perennial habitats since its introduction to the state in the late 1800s. Canada thistle is commonly found in crop fields, pastures, hayfields, CRP, and other full sun habitats. While fall is typically the best time to manage this weed species, late spring, when Canada thistle plants are in the bud or early bloom stage, is a close second for providing consistent herbicidal control.
-
May 26, 2021Authors
Multiflora rose (MFR) is a common weed in pastures, CRP, timber and other areas that are not annually disturbed. Now is an appropriate time for treatment of these weeds in pastures and other areas they invade.
-
May 13, 2021Authors
Iowa’s most significant soybean insect pest, soybean aphid, has host-alternating biology. Its primary host is buckthorn, an invasive shrub often found in hedgerows and roadside ditches, and its secondary host is soybean. For the majority of the year, soybean aphids exist as cold-hardy eggs on buckthorn branches near leaf buds. As spring temperatures increase, the eggs hatch and a few generations are produced on buckthorn before moving to soybean.
-
May 11, 2021Authors
Black cutworm (BCW) is a migratory pest that arrives in Iowa with spring storms each year. It is sporadic and unpredictable, making it essential to scout to determine whether BCW larvae are present in a field and management is required. Since much of the corn planting around the state is complete and many fields have emerged, now is a good time to begin scouting for larvae.
-
May 11, 2021Authors
Performance of preemergence herbicides in many areas of the state may be less effective than normal due to limited rain following application. Although weed emergence following planting was reduced by dry soils and cool temperatures, it is likely that most fields will have some weeds that emerged during this period. Systematic scouting of fields, beginning shortly after crop emergence, will be essential to determine how best to manage weeds throughout the remainder of the season.
-
May 10, 2021Authors
Pesticide applicators and handlers need to wear, at a minimum, the Personal Protective Equipment (PPE) specified on pesticide product labels. Most pesticide labels require a long-sleeved shirt and long pants. Proper laundering of work clothes that may be contaminated with pesticide residues is essential to reduce pesticide handlers’ short- and long-term exposure to pesticides and prevent the potential of residue cross-contamination onto other clothing.
-
May 5, 2021Authors
The growth and development of alfalfa is affected by many factors, including temperature, soil moisture, stand age and even cultivar. Alfalfa growth has been slower than normal due to cool conditions in April. This is a good reminder that using a calendar date to determine when to harvest the first crop of alfalfa may not the best method.
-
April 21, 2021Authors
Bean leaf beetle adults (Photo 1) are susceptible to cold weather and most will die when air temperatures fall below 14°F (-10°C). However, they have adapted to winter by protecting themselves from harsh temperatures under plant debris and loose soil. Each spring, adult beetles emerge from their overwintering habitat and migrate to available hosts, such as alfalfa, tick trefoil, and various clovers. As the season progresses, bean leaf beetles move to preferred hosts, like soybean.