Utilizing Pumpkins as a “Reverse” Trap Crop Essay Example

Utilizing Pumpkins as a â€Å"Reverse† Trap Crop Essay In the world of agriculture, trap crops are normally used to lure pests away from a commercial crop by presenting the pest with a more attractive alternative. But when conducting research to develop new seed traits that provide better yield, drought resistance, or even insect resistance, trap crops can be used to test the performance of a new trait.The western corn rootworm beetle (Diabrotica virgifera virgifera) causes billions of dollars in damage to corn crops throughout the United States each year. Recent seed research has helped develop new corn varieties to combat this problem. These new varieties of corn have a protein (Bt protein) that causes stomach distress in adult western corn rootworm beetles that result in death. Thus, the pest resistance is literally bred into the seed, eliminating the need for harmful pesticides. This type of corn is considered to be rootworm resistant.Normally, in order to be able to â€Å"test† the performance of a specific rootworm resistant corn variety, a test plot has to be infested with western corn rootworm eggs manually. This tends to be costly and very labor intensive. The infested eggs then develop into larva, which feed on underground roots. Adult rootworms feed on the above ground tissue of the corn plant. Both the roots and the above ground tissue contain the Bt protein. The corn plant is then â€Å"harvested† prior to the pollination period in a process called a â€Å"root dig†.During a ‘root dig† the corn plant is cut off at approximately two feet above the ground, the roots are dug up and rinsed with a high power stream of water to expose the roots which are then rated for damage by the corn rootworm larva. Based on the data collected during the â€Å"root dig†, researchers are able to evaluate the effectiveness of the resistance that is bred into that variety of corn. Root dig washing process is shown in picture on the left. Diagram of corn root damage by corn rootworm be etles is shown in picture on the right.HYPOTHESIS: What if one could utilize a â€Å"trap crop† to entice the adult western corn rootworm beetle to a test plot, allowing the adults to feed and eventually lay their eggs? I predict that by adding pumpkins (independent variable) as a trap crop in rootworm resistant corn will allow for a greater number of eggs (dependent variable) to be deposited in the test plot naturally versus the rootworm resistant corn without the trap crop, therefore eliminating the need for manual infestation.To test this hypothesis, we selected pumpkins to plant as a trap crop in a one acre square plot containing rootworm resistant corn. This would be the independent variable in this experiment. It is known that the adult western corn rootworm beetle is highly attracted to pumpkin vines and flowers. A second test plot of the same size (same farm) would be planted with the same variety of rootworm resistant corn without the pumpkin crop. The dependent vari able would be the egg counts in both test plots. The control in this experiment would be utilizing acreage on the same farm.Special steps were taken to replicate the exact soil conditions by a pre-planting soil analysis; utilizing the same â€Å"batch† of chemical in herbicide spray applications, and the close proximity to each other to control factors such as precipitation, number of days with full sunshine, humidity, etc. This will aid in controlling the experiment’s internal validity and act as a guide in any subsequent replications of this experiment. Adult western corn rootworm beetles are shown on a pumpkin flower in the picture on the left.Damage by rootworm beetles on a mature pumpkin shown in picture on the right. Pumpkins were planted in the test plot # 2 in the spring of 2012 and were allowed to mature naturally. During flowering, a sizable increase in the adult rootworm beetle was observed in test plot #2. Based on the observable increase in adults, we pred icted that there will also be an increase in the number of eggs in said test plot when compared to the number of eggs in the test plot without trap crop (pumpkins). Soil samples will then be collected and analyzed for egg counts.If it is proven that planting a trap crop increases egg counts naturally, there could be a considerable cost savings in the process of evaluating the effectiveness of desirable traits in corn. This experiment was conducted at an agricultural Ramp;D site in northwestern Indiana during the summer of 2012 in preparation for this task. Egg count data has been received and is currently being evaluated in preparation for the 2013 planting season. In preparation for this experiment, several independent scientific papers were reviewed. Sorghum as a Trap Crop for Nezara viridula L. (Heteroptera: Pentatomidae) in Cotton in the Southern United States†, P. G. Tillman (1); â€Å"Case Study: Trap Crop with Pheromone Traps for Suppressing Euschistus servus (Heteropt era: Pentatomidae) in Cotton†, P. G. Tillman and T. E. Cottrell (2) and â€Å"Trap Cropping to Manage Green Vegetable Bug Zezara viridula (L. ) (Hereroptera: Pentatomidae) in Sweet Corn in New Zealand†, James H. Rea, Stephen D. Warren, Richard Sedcole, Peter J. Cameron, Stuart I. Davis, R. Bruce Chapman (3) were considered for background information.These studies were helpful in explaining the commercial use of trap crops as an effective method of removing pests from cash crops and served as a basis for our unique application of a â€Å"reverse† trap crop in testing the effectiveness of ongoing corn research. Testing methods were similar but our research did not include any type of Pheromone study. Our experiment was based on the premise that by planting pumpkins in the test plot (known to attract western corn rootworm beetle), we could naturally increase the numbers of western corn rootworm beetle eggs in that plot.An increase in the number of naturally occurrin g eggs could result in a significant reduction in our annual research expenses. - KEY WORDS:western corn rootworm beetle (Diabrotica virgifera virgifera), trap crop, rootworm resistant corn. - METHODS and MATERIALS: This experiment was conducted at a seed research and development facility in northwestern Indiana during the 2012 growing season in preparation for RINT Task 3.This method of scientific design was chosen because it is a replication of a similar experiment conducted at a research and development facility in Iowa and has shown viable results. It was designed to compare the viability of planting a trap crop to attract the western corn rootworm beetle to evaluate the performance of corn containing rootworm resistant traits from different areas of the Midwest. The acreage, chemicals, sampling tools and laboratory facilities were readily available. In addition, if the hypothesis can be proven to be true, there is a potential for cost savings in other areas of our research.Inse ct Species: Western corn rootworm beetle (Diabrotica virgifera virgifera). Corn rootworm larvae can destroy significant percentages of corn if left untreated. In the United States, current estimates show that 30 million acres (120,000  km? ) of corn (out of 80 million grown) are infested with corn rootworms and that area is expected to grow over the next 20 years. The USDA estimates that corn rootworms cause $1 billion in lost revenue each year, which includes $800 million in yield loss and $200 million in cost of treatment for corn growers (The Dow Chemical Company). (4)Shown above from left to right, corn plant damage in the field and examples of actual root damage done by western corn rootworm beetles in the center and right picture. Healthy roots are shown as a full root system; damaged roots are short to nonexistent. Sampling Technique: Using a golf course cup cutter, take 4† diameter x 4† deep soil core samples. Collect ten (10) core samples per acre (trial area) . Core samples should be taken at various locations within the test plot. Include samples taken from within the corn rows and between rows. Place core samples in individual gallon bags.Be sure to break up any large clumps and remove stalks and other residue. Making the soil as fine as possible will aid in the washing process. Send individual samples to a laboratory with capabilities to wash eggs and provide egg counts. Taking multiple core samples at various locations throughout the test plot and then analyzing all ten (10) samples separately allows for a broader analysis of the entire test plot. The measuring unit of one (1) pint that was chosen for the final sample allows the lab sufficient soil to run the required tests.Once the samples arrive at the laboratory, each individual sample is mixed with a saturated salt solution. A sample of this mixture is then placed on a special microscope slide (Whitlock Universal or Whitlock McMaster). The saturated salt solution makes the rootwo rm eggs float to the top of the mixture in the slide where they are then counted. Data was collected from each individual sample to obtain egg counts for each test plot. EXPERIMENT: Two, one (1) acre test plots were selected at opposite ends of a ten (10) acre field. Soil type, topography, and precipitation were identical.Each plot was measured at 200 ft. wide by 220’ deep and marked off with flags. This is approximately one (1) square acre. Both fallow (empty ground) test plots were plowed utilzing a chisel plow set at a depth of six (6) inches to turn the soil over and prepare the soil for planting. Both test plots were then planted using a four (4) row custom bulk planter and a rootworm resistant variety of corn. The corn rows were spaced 30† apart. The corn seed within the rows was spaced 6† inches apart. Each test plot had a total of 80 rows of corn. Both test plots were also treated with Glyphosate in a concentration of 1. quarts to 15 gallons of water to ki ll any existing weeds. This amount of Glyphosate solution was enough to cover one (1) test plot. It was replicated twice to cover both test plots in the experiment. Once the rootworm resistant corn had been planted in both test plots, a trap crop of pumpkins was also planted throughout the test plot #2 (independent variable), utilizing a custom two (2) row planter. Pumpkin seeds were planted in between the rows of corn, spaced five (5’) feet apart. A cable winder was used to mark off the five (5’) foot increments needed to plant the pumpkins.A cable winder is used with a custom planter and calibrated to â€Å"click† when it is time to manually drop the seed. Both plots were allowed to grow throughout the summer. Visual observations were made in each plot, on the first Monday of each week between July 1st and September 1st to obtain adult rootworm beetle population counts. Ten observations in multiple locations across the test plots were taken each time. Random p umpkin plants were selected to count the total number of adult rootworm beetles in each observation. After harvest, prior to the first hard frost, soil core samples were taken, following the above mentioned sampling procedure.Core samples were then sent to an outside laboratory for analysis. - RESULTS: An increase in adult rootworm beetles was observed in test plot #2 (with pumpkins) when compared to test plot #1 (without pumpkins) but without soil egg count analysis, this data in inconclusive. Solid data is available once soil samples are analyzed for egg counts (dependent variable). Historically more than ten (10) eggs in a pint sample of soil are considered to be a high amount. In 2012, test plot #1 and #2 both showed an average of approximately two (2) eggs per pint sample.Samples taken at four different test sites in Iowa yielded six (6), zero (0), one (1) and four (4) eggs respectively or an average of 2. 75 eggs per pint sample. All data collected is reflecting little to no m easurable increase in the total number of western corn rootworm eggs that are occurring naturally when using a trap crop. Egg Count Core Sample Data for Test Plot #1 and Test Plot #2 Test Plot #1|   |   | Test Plot #2|   | |   |   |   |   | Core Sample #| Egg Count #|   | Core Sample #| Egg Count #| 1| 0|   | 1| 0| 2| 1|   | 2| 3| 3| 0|   | 3| 2| 4| 1|   | 4| 2| 5| 4|   | 5| 3| 6| 3|   | 6| 2| | 2|   | 7| 1| 8| 2|   | 8| 0| 9| 1|   | 9| 2| 10| 0|   | 10| 2| Ave # of Eggs| 1. 4|   | Ave # of Eggs| 1. 7| Egg Counts in Test Plot #1 Compared to Test Plot #2 Number of Eggs/Pint Sample Number of Samples/ One (1) Acre Test Plot - CONCLUSION: Based on the data that was collected, there did not seem to be a significant increase in the number of western corn rootworm eggs occurring naturally in test plot #2 when compared to test plot #1, even though there was an observable increase in adult western corn rootworm beetles in test plot #2.Where test plot #2 contained the trap crop (independent variable) and test plot #1 that did not contain a trap crop (dependant variable) in a single ten (10) acre test strip (constant variable). After carefully analyzing the data that was collected during this experiment, I have concluded that the introduction of a trap crop (pumpkins) to attract adult western rootworm beetles in rootworm resistant corn does not significantly increase naturally occurring corn rootworm beetle eggs. This data disproves my hypothesis that it would significantly increase the number of naturally occurring eggs.No cost savings can be associated with this experiment and conventional infestation methods are just as effective as this experimental method. DESIGN AND REPLICATION: The experimental design to test this hypothesis was constructed with ease of replication in mind. It utilizes simple techniques and materials that are readily available at most seed research and development sites. If the design is poor or if proper samp ling procedures are not followed then data in the experiment can be skewed, resulting in unreliable data.Based on potential cost savings in research, unreliable data can be an expensive mistake. In addition, if the design is well done, an increase of reliable data is shown time and time again with the same results. Replication is so important because it gives validity to the experiment’s results. As the same data shows the same results and the same conclusions over multiple replications, that data can become accepted as scientific fact. REFERENCES: (1) http://www. ars. usda. gov/sp2UserFiles/person/5648/PDF/ARIS 8-Sorghum as a Trap Crop for SGSB. d Tillman, P. G. 2006. Sorghum as a trap crop for Nezara viridula L. (Heteroptera: Pentatomidae) in cotton in the southern United States. Environmental Entomology. 35(3):771-783. (2) http://www. hindawi. com/journals/psyche/aip/401703 Tillman, P. G. , Cottrell, T. E. 2012. Case Study: Trap crop with pheromone traps for suppressing eu schistus servus (Heteroptera: Pentatomidae) in cotton. Psyche. DOI: 10. 1155/2012/401703. (3) http://onlinelibrary. wiley. com/doi/10. 1046/j. 1461-9563. 2002. 00130. x/full Rea, J.H. , Wratten, S. D. , Sedcole, R. , Cameron, P. J. , Davis, S. I. and Chapman, R. B. (2002), Trap cropping to manage green vegetable bug Nezara virdula (L. ) (Heteroptera: Pentatomidae) in sweet corn in New Zealand. Agricultural and Forest Entomology, 4: 101-107. doi: 10. 1046/j. 1461 (4) http://en. wikipedia. org/wiki/Diabrotica_virgifera; The Dow Chemical Company. Product Safety Assessment (PSA): Herculex RW Rootworm Protection. September 26, 2006. URL: http://www. dow. com/productsafety/finder/herculex. htm.