Recent Research Results:

Final Report to Pennsylvania Soybean Promotion Board
(For complete report click here)

Research to develop an Integrated Pest Management Program for Soybean Aphid, Aphis glycines, to the serve the Pennsylvania and Mid-Atlantic region has been ongoing for four years. The soybean aphid was first officially recorded in Pennsylvania in 2001, but was likely to have been present prior to this time. Early surveys for the pest found it in all counties of the state. Today, it is can easily be found in all Pennsylvania counties that produce soybeans.

Research to develop a soybean aphid IPM program has been focused on improving our understanding of its biology and population dynamics. The three major research focus areas are: 1) quantification of damage-loss relationship to estimate economic thresholds, 2) temperature dependent development studies for the development of a stage specific phenology model, and 3) field level population dynamics studies.

For this project funded by the Pennsylvania Soybean Promotion Board, the major objectives were: 1) quantify developmental rates of soybean aphid life stages for use in the development of a model that predicts timing and magnitude of infestations, 2) investigate the field colonization rate of aphids and the role that predators, parasitoids, and disease organisms play in pest population buildup and decline, and 3) establish economic thresholds for soybean aphid management.

Simulation of Monarch Life Stages and the Corn
Pollination Period
(For the complete report, follow this link.)

The goal of the present study is to determine which monarch life stages are coincident with corn pollination at a selected number of locations. In particular, the study focused on the timing of the first three monarch instars, with respect to corn pollination period. The first three larval instars are considered to be the most sensitive to Bt pollen and likely to experience lethal and nonlethal effects, if present, during corn pollination.

Two models were constructed to carry out separate simulations of monarch and corn development over the growing season. The results of these model simulations were overlaid on each other and presented in graphs to illustrate when a particular monarch life stage is likely to interact with corn pollen. As mentioned earlier, the most important overlap is when the first three instars are coincident with corn anthesis. The underlying goal of the modeling effort was to determine if a particular monarch instar occurred during corn pollination. The models were not concerned with predicting monarch population density or risk of exposure. What the model output provides is a picture of which monarch life stages are present at a given geographic location during the corn pollination period.

Both monarch and the corn developmental models required weather data as input. These data came from the 1961-90 climatography issued by the National Climatic Data Center (NCDC). The data were in the form of hourly temperatures derived from 30-year monthly averages for stations located in the states selected for the study.

Verification of Monarch Phenology and Corn
Pollination Models
(For the complete report, follow this link.)

The present document is a follow-up to an unpublished study entitled "Simulation of Monarch Life Stages and the Corn Pollination Period" (Calvin, et al., 2000). In the earlier study, simulated monarch development stages and the corn pollination periods were generated for selected sites using 30-year (1961-90) hourly temperature averages (National Climatic Data Center) as input.

The goal of the earlier study was to determine if the first three monarch instars were coincident with corn pollination periods at the selected locations. The premise was that the early instars (smaller larvae) would be more sensitive to the Bt concentrations in pollen than late instars (larger larvae). Coincidence, if confirmed, would provide some indication of possible exposure of the monarch butterfly to Bt pollen. Since climatological data were used as input into the models, the coincidence of monarch stages and pollination periods could not be verified in the field. The goal of the present study was to overcome this limitation. It was to verify the monarch phenology and corn pollination models by using weather data for specific years in addition to climatological records.

The verification process required two data sets. First, monarch life stages, in particular the first three instars, and corn pollination periods had to be simulated using seasonal temperature data. Second, the simulations had to be made for locations where monarch field data were being collected for a given year. Several entomologists across the United States were enlisted to collect monarch data. They periodically surveyed a corn field over the course of a growing season and recorded monarch butterfly numbers and stages. The verification process included comparisons of the simulated and observed monarch stages and pollination periods for selected sites. Before discussing the comparisons between simulated and observed monarch and corn data, it may be helpful to review the models, which were previously described in detail in the earlier study by Calvin, et al. (2000).

Soybean Aphid Interim Report - 2003
(For the complete report, follow this link.)

Study Objectives:

1. Conduct growth chamber experiments to quantify developmental rates of soybean aphids and develop models that predict timing of infestations.
2. Investigate field colonization rate of soybean aphids and the role of predators, parasitoids, and disease organisms in regulating buildup of the pest.
3. Establish Economic Thresholds for Soybean Aphids.

Soybean Aphid Research Report - 2002
(For the complete report, follow this link.)

Study Objectives:

Survey Pennsylvania soybean fields to determine the presence and intensity of soybean aphid and bean leaf beetle populations

Determine the seasonal dynamics of the soybean aphid

Evaluate key soybean insecticides for efficacy against the soybean aphid

Evaluate differences in soybean varieties susceptibility to the soybean aphid

Assess the success of grower's in meeting their soybean stand goals

Incorporating Bt-corn Hybrids into Field Crop IPM Programs
(For the complete report, follow this link.)

From 1 July 2001 to June 30, 2003, field and laboratory studies were conducted to assess the yield performance of Bt-corn hybrids relative to their near isoline and leading non-Bt hybrids across multiple production zones in the Northeast. In addition, studies were conducted to determine if Bt-corn isoline base genetics and leading conventional hybrid genetics were equally susceptible to injury from European corn borer. Using this information and a region wide survey of European corn borer infestation levels, the economic value of Bt-corn hybrids to Northeast corn producers was estimated. Finally, using information from the above studies, an extension publication is being developed to assist corn producers make rational decisions about the economic value of using these hybrids. Below is a bulleted summary of key finding from this research/extension project. Appendices I & II are research papers submitted for publication from this work.

Economic Benefits of Transgenic Corn Hybrids for European Corn Borer Management in the United States. A Report to the Monsanto Company. (Links to: Part 1, Part 2, Part 3, Part 4, Part 5, Part 6, Part 7)
(For the complete report, follow this link.)

Abstract: ...The use of genetically modified corn hybrids that contain a gene to produce the delta-endotoxin of Bacillus thuringiensis subspecies kurstaki will help many farmers recover yield lost from eCB infestations. Transgenic corn hybrids provide protection from the ECB using a pesticidal protein that is produced by the plant over the plant's growth period. Because the pesticidal protein is produced by the plant, there is no cost for an insecticide and its application or associated scouting costs. The only cost associated with a transgenic corn hybrid is the premium on a bag of seed. A seed corn premium of $3.00 to $10.00 per acre would result in lower economic thresholds for ECB management than current insecticide based management programs. Implementation of this new technology, therefore, would allow U.S. farmers to recover significantly more of the yield lost to ECB feeding at a lower cost. The use of genetically modified corn hybrids would have additional benefits, including increased farm worker safety and decreased pesticide rinsate and container disposal problems.