Now is the Time to Sample for Corn Nematodes
By Greg Tylka, Department of Plant Pathology
Integrated Crop Management News
Links to these articles are strongly encouraged. Articles may be republished without further permission if published as written and if credit is given to the author, Integrated Crop Management News, and Iowa State University Extension and Outreach. If articles are used in any other manner, permission from the author is required.
Reviewing Decision Thresholds for Pest Insect Control
By Jon Tollefson, Matt O’Neal, and Marlin Rice, Department of Entomology
Three tools need to be understood in order to make decisions regarding the control of insects found on crops: damage boundary, economic injury level, and the economic threshold. The existing values for these three variables are now being questioned with the increase value of Iowa’s row crops and the cost of controlling the pests. This article reviews the use of these tools in regards to soybean aphid control.
Preventative vs. Curative Fungicides
By Daren Mueller and Alison Robertson, Department of Plant Pathology
We have received several questions about selection of fungicides, especially with regards to deciding between “curative” and “preventative” fungicides. People want to know if they should be applying a strobilurin fungicide, triazole fungicide, or a premix of both.
Is that Common or Southern Rust Showing up in Iowa Fields?
By Alison Robertson, Department of Plant Pathology
Is that common or southern rust showing up in Iowa fields? Chances are it is common rust. It has probably been too cool and wet so far this growing season to see southern rust. Symptoms of the two rusts are very similar but there are subtle differences.
Soybean Cyst Nematode Females now Apparent on Soybean Roots
by Greg Tylka, Department of Plant Pathology
Many Iowa soybean fields may be infested with the soybean cyst nematode (SCN) but the infestations may not be known because SCN does not always cause obvious, above-ground symptoms. In fact, yield loss of up to 40 percent has been documented without above-ground symptoms occurring.
Renovating Pastures or Hay Meadows Damaged by Flooding
By Stephen K. Barnhart, Department of Agronomy
Flooding has damaged pasture and hay meadows across the state of Iowa. While most forage will likely recover, other areas that were eroded or silt- or sand-covered will require some reseeding. The following considerations may guide you in your planning and management.
Yellow corn, Wet soils, and Nitrogen loss (Part 3)
by John Sawyer, Department of Agronomy
Earlier I provided observations in two articles (June 19 and June 26, 2008) on corn growth and response to nitrogen (N) applied in an anhydrous ammonia study being conducted at the ISU research farm between Ames and Boone. Following are some final observations (July 7, 2008).
Reseeding Flood and Weather-Damaged Forage Crops in Late Summer
By Stephen K. Barnhart, Department of Agronomy
New forage seedings are susceptible to a wide array of problems and stresses -flood, hail, drought, weed competition, insects, etc. Late summer can be a good time to ‘patch in’ bare or thin spots in forage stands or reseed entire fields. However there are some risks. The following steps will improve the chances for successful forage stand establishment in late summer.
Managing CRP for Hay or Pasture
By Stephen K. Barnhart, Department of Agronomy
Corn Following Corn in 2008
By Mahdi Al-Kaisi, Roger Elmore, Antonio Mallarino, Palle Pedersen, Alison Robertson, John Sawyer, and Jon Tollefson