Soybean aphids on the go: Results from the suction trap network

Since the soybean aphids\u27 arrival in North America during 2000, there has been much speculation about how this new pest will establish and thrive. On-the-ground estimates have been helpful in measuring the range of this invasive species--currently, it is found in more than 22 states and three Canadian provinces

2005 Wrap-up

The 2005 growing season left many growers with very different experiences managing insect pests in soybeans. Aphids were feared to return to economic populations, and for nearly 2 million acres in Iowa, they did. However, many growers reported fields with 250 or more aphids per plant next to fields that had few if any aphids. I was a bit skeptical of this last observation, but such a situation occurred next to one of our research plots in Story County. Just as one would expect, the field that we had carefully marked and planted for research had a sub-economic population of soybean aphids

Different thresholds, different states: Why?

By now you have heard the story: there are two economic thresholds suggested for managing soybean aphids--10 or 250 aphids per plant. The difference is remarkable for anyone who has scouted for soybean aphids in Iowa. At 10 aphids per plant, it\u27s hard to imagine a year when we would not treat possibly millions of acres of soybeans in Iowa. Although 10 aphids per plant can reproduce into hundreds if not thousands per plant, this type of dramatic outbreak has not occurred consistently in Iowa. During the 2004 growing season, it was uncommon for fields in Iowa to reach even 100 aphids per plant

Field-based Research Experience in Earth Science Teacher Education

This is an overview of a field-based research experience in Earth Science teacher education program that was conducted for secondary science teachers from Prince George's County, Maryland. The goal of the program was to produce well-prepared, scientifically and technologically literate Earth Science teachers through a teaching- and research-oriented partnership between in-service teachers and a university scientist-educator. Program participants were exposed to a broad background in field-based instruction in physical, historical, and environmental aspects of Earth Science content and teaching methods, followed by participation in an authentic, technology-rich field research project. Although attrition rates were high, program participants indicated that they were more confident in their Earth Science content knowledge and teaching ability than they had been initially. All respondents also indicated that they were currently using methods, strategies, and activities they had learned in the program within their own classrooms. Educational levels: Graduate or professional

Survey: Are insecticide/herbicide tank mixes commonly used?

Last week, Carol Pilcher, Marlin Rice, and Todd Vagts reported results from several surveys conducted in 2003 illustrating the economic impact of the soybean aphid. This article presents a followup from a survey given to commercial pesticide applicators attending the Iowa State University Commercial Agriculture Videoconference during February 2005. A similar survey was given to growers throughout Iowa by Marlin Rice during winter 2004 and is part of a larger multi-state project that includes Wisconsin, Minnesota, and Michigan. We will review the results of the multi-state grower survey later in the summer

Soybean insecticides for 2007

Soybeans typically harbor an incredible diversity of insects that feed on the plants from the time they start to crack the soil until the last leaf has dropped in the late summer. And somewhere between these two extremes, insect and spider mite populations occasionally build up to economically damaging populations. When this happens, often the most effective pest management tactic for most growers and crop managers is to apply a foliar insecticide to reduce the population

Management options for soybean aphids

If producers need to treat for soybean aphids this year, Iowa State University (ISU) has recommendations on when and how insecticides should be used to manage this pest. Do not use insecticides when small populations of soybean aphids are first found in the field. Natural enemies may help suppress small aphid populations. Producers should determine if the aphid population is increasing or decreasing

Soybean aphids scattered across Iowa

Soybean aphid populations remain at low densities in monitored fields across the state, but the known distribution for 2006 now covers most of Iowa. On June 19, Extension field crops specialists reported soybean aphids from northeastern (Allamakee, Clayton, Winneshiek counties), southeastern (Lee County), central (Story County), and northwestern Iowa (Cherokee County). Aphid densities were less than one aphid per plant in all counties. In the June 5 newsletter, we reported an aphid colony containing 40 insects, but two weeks later when 80 plants were inspected in the same field, only a single plant was found with only four aphids on it

Soybean aphid numbers increase...and decrease

As might be expected, soybean aphid populations have increased slightly in some locations around Iowa. The most notable increases, although they have been small, were reported from northeastern Iowa by Brian Lang, extension field agronomist in Decorah. The average number of aphids per plant increased from 6.6 to 30 with the percent infested plants also increasing from 59 to 95 percent (Table 1). The population in northeastern Iowa most closely parallels the same trends from 2005 with respect to aphid numbers and percent infested plants. Fortunately, we are not yet observing a population increase that would mirror the major outbreak year of 2003, and that is good news