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

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

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

Hot, dry weather mite be a problem: Two-spotted spider mites infesting soybeans

Adding insult to injury, the dry conditions that many growers are experiencing in eastern Iowa and Illinois are bringing additional problems: two-spotted spider mites. These eight-legged arthropods feed on a variety of plants and are typically not a pest of soybeans during cool, humid summers. Under these conditions, the mites are kept in low numbers by fungi that attack arthropods. When this control is disrupted, spider mites are capable of reproducing quickly in large numbers

A soybean is a soybean is a soybean: Do aphids reproduce the same on all varieties?

Since the soybean aphids\u27 arrival in Iowa, many growers have observed that soybean aphid outbreaks vary across different varieties of soybeans. As mentioned in earlier articles within this special edition, several factors can influence soybean aphid population growth (plant health, predators, overwintering success). Adding to the factors that influence aphid population growth is variation in soybean aphid response to different varieties of soybeans, but the source of this variation is unclear. Typically, external features like leaf hairs or internal factors that contribute to aphid feeding (antibiosis) can influence how well an aphid population grows on a given plant

Soybean aphids and K-deficient soybeans: Why are there aphids in my field and not my neighbor\u27s?

There were frequent reports of fields infested above 250 soybean aphids per plant adjacent to those with lower populations that never reached threshold. The lowest aphid populations were seen in the southern tier of Iowa counties. However, Mark Carlton, extension field crop specialist in southeast Iowa, called me several times during the season to report that he had scouted fields that were above threshold. By the third call, it became a bit of a routine, with each field sharing some remarkable similarities

Soybean aphid suction trap network up and running in Iowa

Funding from the North Central Soybean Research Program and the North Central Integrated Pest Management (IPM) Center allowed the soybean entomology lab at Iowa State to establish four soybean aphid suction traps during the 2005 growing season. The traps are designed to capture soybean aphids as they migrate to new soybean fields or back to buckthorn, their overwintering host. The traps are composed of a 20-foot vertical tube with an electric fan at the base. The fan pulls air through the tube and deposits aphids into an alcohol-filled jar. The jar is replaced every week and the contents are sent to David Voegtlin at the Illinois Natural History Survey

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

Soybean Aphid Aphis glycines Matsumura (Homoptera: Aphididae) Suction Trap Monitoring Network in Iowa

Beginning in July 2005 the Soybean Entomology Laboratory established four suction traps within Iowa. These suction traps have helped entomologists and growers understand the year to year variability in soybean aphid populations