Progress 10/01/04 to 09/30/07
Outputs
OUTPUTS: Activities: Seed Corn Maggot: A series of field experiments over the three years of this proposal were conducted to determine the relationship of stand losses from seed corn maggot feeding and resultant yield losses of grain. A single adapted variety of soybeans was planted using current commercial practices and seeding rate on the Cornell Musgrave farm located near Aurora, NY. Shortly after plant emergence, seed corn maggot damage was simulated by plant removal. Stand losses simulated were 0, 10, 20, 30, 40, and 60 percent. Plots were harvested, yield data was collected and yield losses was correlated to damage levels. Year Soybean Aphid: The impact of soybean aphid on NYS adapted soybeans was examined using timely treatments of insecticides to eliminate aphids during the desired plant growth stage and for the remainder of the season. A single soybean variety was utilized. The following experimental regimes were established and maintained. 1) Season long aphid control. 2)
Aphids eliminated during pre-bloom and maintained for the remainder of the growing season. 3) Aphids eliminated during bloom and maintained for the remainder of the season. 4) Aphids eliminated during pod-fill and maintained for the remainder of the season. 5) Aphids eliminated during post-pod fill and maintained for the remainder of the season. 6) No control of aphids during the season. The timing of crop colonization by the winged stage of soybean aphid was studied using yellow pan traps to identify the flights into fields from the over wintering hosts outside of the fields. Events: Both series of experimental plots were located on the Cornell Musgrave farm located near Aurora, NY. In two of the three years of this research, the experimental plots were a tour stop on the annual Aurora Farm Field Days.
TARGET AUDIENCES: The target audience for this research was the soybean growers of NYS. Information was dispersed to the target audience through extension eduational winter meetings and summer Aurora Farm tours.
Impacts
Seed Corn Maggot: A moderate infestation of SCM can reduce the stand of soybeans by 4 percent and reduce the yield of soybeans by 3 bushels per acre when planted at a drop rate of 200,000 seeds per acre. Depending on the price of soybeans, this loss ranges from $18-24 per acre. A seed treatment of insecticide active on seed corn maggot ranges from $2-10 per acre and results in a net profit of $13-19 per acre. The impact of seed corn maggot feeding was studied by planting soybeans at three different densities and then thinning each density at four different levels. Stands were thinned shortly after plant emergence. Plots were then protected from insect injury until harvest when the impact of the different treatments were measured. The three seeding rates were 150,000, 200,000 and 250,000 seeds to the acre. The thinning rates were 0 pct, 10 pct, 25 pct and 50 pct. At the highest seeding rate, the yield of the 0 pct, 10 pct, 25 pct and 50 pct were not significantly
different. At the medium seeding rate, there was no significant difference between the yield of the 0 pct, 10 pct and 25 pct thinning rate. The numerical differences followed a logical pattern with 0 pct thinning having the highest yield and the 50 pct thinning having the lowest yield At the low seeding rate, there was no significant difference between the 4 thinning rates. This study shows that soybeans have a large potential to recover from early stand loss with the remaining plants filling the open spaces and compensating with increased yield. There were no significant differences in yield from plant stands with 112,000 plants to 250,000 plants per acre. Soybean Aphid: Soybean aphid is primarily a long-ranged migrant which enters NYS on favorable winds/weather systems from the overwintering areas located to the north and west of NYS. There is a small localized population which overwinter on local hosts. Three years of yellow pan trap data indicate that the local aphids begin
colonizing soybeans in late May through mid-June. These flights were always very light and never resulted in an economic population in the experimental plots. Around the first of July, the yellow pan traps detected an influx of aphids considered to be long-ranged migrants because their appearance followed the passing of a weather front. This weather front connection is typical of long-ranged migrants of many species. In spite of aphids colonizing the experimental plots each year from both local and distance sources, economic populations never established through the 3-year window of this project. Without an economic population, the experiments could not be conducted. Change in actions: Seed Corn Maggot: Soybean seeding recommendations made by Cornell Extension specialists have been changed as a result of this research. Not only does this information focus on seed corn maggot stand loss but also focuses on the impact of stand loss from soil crusting and seedling pathogens. Recommended
seeding rates will be reduced from 200,000 seeds per acre to 180,000 seeds per acre.
Publications
- Cox, W. J. and E. J. Shields. 2007. When to palnt soybeans in New York. What's Cropping Up? 17 (2): 1.
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Progress 01/01/06 to 12/31/06
Outputs
Simulated Seed corn maggot injury: Seed corn maggot frequently thins soybean stands during plant emergence. The impact of seed corn maggot feeding was studied by planting soybeans at three different densities and then thinning each density at four different levels. Stands were thinned shortly after plant emergence. Plots were then protected from insect injury until harvest when the impact of the different treatments were measured. The three seeding rates were 150,000, 200,000 and 250,000 seeds to the acre. The thinning rates were 0 pct, 10 pct, 25 pct and 50 pct. At the highest seeding rate, the yield of the 0 pct, 10 pct, 25 pct and 50 pct were not significantly different but there were numerical differences with the 10 pct and 25 pct higher than the 0 pct and the 50 pct thinning rate was the lowest. At the medium seeding rate, there was no significant difference between the yield of the 0 pct, 10 pct and 25 pct thinning rate. Also, there was no difference between
the 25 pct and 50 pct thinning rate. The yield at the 50 pct thinning rate was significantly lower than the 0 pct and 10 pct thinning rate. The numerical differences followed a logical pattern with 0 pct thinning having the highest yield and the 50 pct thinning having the lowest yield At the low seeding rate, there was no significant difference between the 4 thinning rates. There were numerical differences with the 0 pct thinning having the highest yield, followed by the 25 pct, 10 pct and then the 50 pct thinning rates. This study shows that soybeans have a large potential to recover from early stand loss with the remaining plants filling the open spaces and compensating with increased yield. There were no significant differences in yield from plant stands with 112,000 plants to 250,000 plants per acre. Plans are in place to repeat this study on a larger scale for the 2007 growing season. Soybean aphid threshold research: Soybean aphid, a long range migrant failed to migrate to New
York in 2006 in sufficient numbers to provide high enough populations in the field for meaningful research. All the research plots were planted in late May 2006 to evaluate Midwest thresholds for soybean aphid injury on New York soybean. However, an insufficient number of aphids arrived from their over wintering area.
Impacts
This research will have an impact on the seeding recommendations made by Cornell Extension specialists starting with the 2007 planting season. Not only does this information focus on seed corn maggot stand loss but also focuses on the impact of stand loss from soil crusting and seedling pathogens. Recommended seeding rates will be reduced from 200,000 seeds per acre to 180,000 seeds per acre for 2007. Perhaps with a second year of data, the recommended seeding rates can be reduced even further.
Publications
- No publications reported this period
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Progress 01/01/05 to 12/31/05
Outputs
A series of three experiments were conducted during the 2005 growing season. All field experiments were conducted at the Musgrave Research Farm located in Aurora, NY. The focus of the first experiment was the impact of seed corn maggot on soybean yield and to quantify the amount of stand reduction which could be tolerated before yield was impacted. The experimental protocol required the planting of an area of uniform plant stand and the stand loss from seed corn maggot injury would be simulated in a very controlled manner by the removal of plants in a specified pattern and quantity. Very dry conditions and lack of rain during the planting/germination period in 2005 resulted in a very uneven stand in the test plot area. The extended spring drought prevented the test area from being replanted so this portion of the experiment was abandoned. The focus of the second experiment was to quantify the impact of soybean aphid management practices on soybean aphid populations
and yield. The experimental protocol specified that the aphid populations would be allowed to become established and build until a predetermined plant growth stage, then the aphid population would be controlled for the remainder of the season. Yield differences would reflect the impact of the aphid population and duration of the aphid presence on the plant. In 2005, soybean aphid, a long-ranged migrant arrived in two different windows. The first arrival was in early June and the number of aphids were very few. We suspect that these aphids were from a local over-wintering source. Insect populations were very slow to build from these initial migrants. A second influx of aphids occurred in early July. After aphid populations increased for 2 weeks and the experiment looked promising, the aphid population suddenly crashed. We suspect that a fungal epizootic killed all the aphids but no infected cadavers were found. The focus of the third experiment was to evaluate the interaction between
planting date, insecticide seed treatment, aphid densities and yield. The plots were established with 3 planting dates, 2 seed treatments, a foliar insecticide and an untreated check. Even with the lighter than expected aphid populations in 2005, there was an interesting interaction between the seed treatments, planting dates and yield. On a single year of data, it would appear that a seed applied systemic insecticide has enough aphid suppression to have a positive impact on soy bean yield.
Impacts
The expected impact of this research is to improve the management of Seed Corn maggot and soybean aphid on soybeans grown in New York State.
Publications
- No publications reported this period
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