Biological Control of Pests

PROJECT BACKGROUND
Our farm operation is a ridge till type cropping system. We have incorporated some lower input strategies within the last few years. We farm and manage 1500 acres of crop land. The major crops for our operation consist of corn and soybeans. We alternate corn and soybeans on all of our acres within a three year period. The corn grown on our farm in commercial yellow. Soybeans grown by us are commercial yellow and Vinton (tofu) varieties. We farm predominantly pivot irrigated ground with a small portion of both gravity irrigation and dry land crop production. We are a family farming operation with a row crop enterprise. We grow broiler chickens and turkeys by grazing them on alfalfa (movement to fresh alfalfa every two days), with a feed ration from our own non-GMO corn, and without the use of antibiotics. We have enjoyed this addition of small livestock into our operation. Years past we have been involved in commercial seed corn and soybean production as well as a small dabbling in vegetable production.

PROJECT DESCRIPTION AND RESULTS
Our objective to develop a cropping system which would provide biological control of crop pests, specifically European Corn Borer. Along with this, we wanted to find what beneficial insects are native to our area, how we could improve their habitat, and how they could be used to help reduce pest pressure in corn. The system must be economically feasible as to provide suitability for a diverse group of farmers in applying the same system to their operations. We intercropped alfalfa with corn (264 corn rows bordered on the east and west with 60 foot strips of alfalfa) in order to research alfalfa’s suitability for habitat of beneficial insects. Also, the application of sugar and yeast treatments on the alfalfa to facilitate growth of insect populations was done. The treatments were integrated to define their importance. We tried to determine the timing of cutting the alfalfa and its importance as well. Both of these were compared and contrasted to find the best possible answer for providing beneficial insect populations to thrive and migrate into our corn field. Hopefully, a benefit of the use of alfalfa is to provide additional income to the operation through the sale of the cuttings of alfalfa. This would be a beneficial financial offset to the reduced corn acres in production.

Process:
We disked up the 60 foot strips for seeding alfalfa. It was seeded in the spring of 1999. the initial stage of the project was complete with a good stand of alfalfa being established in early in the year. The second phase of the project consisted of collection of data. This collection took place June 9-August 10, 1999. Alfalfa was allowed to bloom, initially, for two weeks and then a cutting was made. No yeast of sugar treatments were made. The second cutting of alfalfa happened right at bloom with treatments of yeast and sugar being applied directly after the cutting. Yeast was applied on one strip of alfalfa while sugar was applied on the second strip of alfalfa. We wanted to isolate the beneficial treatment if there was one. The third and final cutting of alfalfa was allowed to bloom for two weeks with treatments of yeast and sugar on their respective strips following the cutting. The yeast and sugar treatments are, theoretically, food sources for the beneficial insect populations while the alfalfa regenerates and provides suitable habitat for insect populations again. We wanted to see if field studies provide the same answer. The collection was done by trained individuals to sweep the alfalfa and corn with sweep nets. Also, sticky traps were used as collection tools for insect identification.

People:
David Kreutz, project leader, and Andrew Christiansen, Hamilton County Extension educator, were working extensively together on this project. Dave provided the necessary labor and physical work for the project. Andy provided much of the collection of data and training. Adena Kreutz, Dave’s wife, along with Erin Whitney and Emily Clark were trained by Andy in collection and identification of insect population collected. This team of individuals was a great asset to the success of this project. The continued timely collection provided valuable research for tabulation. Paul Huenefeld, neighbor, worked with us in an advisory role. He provided valuable application suggestions in trying to implement this into a farm operation rather than just research situations. His valuable insight as an organic producer was welcomed as he shared with Dave and Andy suggestions and questions. Sam Moyer, bank president, provided community encouragement to persevere in seeking out a viable alternative to chemical insect control. He talks with many farmers and provided the necessary questioning of implementation of this strategy for insect control into his clients farming operation. He helped keep this at the forefront of our minds as the project progressed. The help and coordination of all of these individuals provided a positive end result for evaluation of the project.

Results:
The project results were not totally definitive. A continuation of the project seems necessary for further data collection. We collected spiders and lady beetles on a regular basis throughout the entire insect collection period (June-August). Green lacewing collection was sporadic with three being caught. Each green lacewing was caught during the sweep before the alfalfa was cut. Spider and lady beetle collection dropped after each cutting of alfalfa. There were no Trichogramma wasps or Brachanid flies collected. Insect movement into the corn field was observed; however, reliable insect collection in the corn field was not feasible as the corn progressed. Definitely, the insects thrived in taller alfalfa. The greatest obstacle to the project was timing the cutting of the alfalfa with the flight and laying and hatching of eggs of the European Corn Borer. We tried to coordinate cuttings with these essential ECB events for optimum data collections. Yeast and sugar treatments made no recognizable differences in the increase of beneficial insect populations. We observed ECB moths, egg masses and worms within the corn field and each level stayed well below emergency treatment thresholds. On other corn fields of ours the same year, it was necessary to treat ECB infestations. Alfalfa is a wonderful flowering crop for insect habitat. However, the use of it in a strip situation is not recommended if one is also trying to sell the alfalfa cutting for income. Allowing the alfalfa to bloom has a significant negative impact on the quality of yield of the alfalfa throughout the year. The field yielded 156 bushels per acre.

These results were not what we expected. We expected more green lacewings and some trichogramma wasps and brachanid flies. However, the numbers of spiders and lady beetles were a positive observation. Also, the difficulty in timing the alfalfa with flowering and cutting was more than anticipated. We realized it would be crucial to the migration of the insect populations; however, we didn’t realize how significant the effect would be on the growth pattern of the alfalfa itself. The thought that significant production of alfalfa will be harvested for sale to offset lost corn production is unrealistic.

We will continue the project nest year and mow the alfalfa without the attempt to cut it for baling and income. We anticipate this will provide us with greater ease in managing its blooming stage for insect habitat development and migration. The interseeding with alfalfa of various clovers is a viable addition to offer a diverse blossom color selection for the inset populations.

Discussion:
We learned so much from this project. We learned, through researching introduction of insect populations, we want to promote the growth of existing insect populations for our area. We learned lady beetles and spiders are most predominant in our area to be made to promote their increase. We learned it is unrealistic to expect trichogramma wasps to participate in a biological insect control situation without their introduction. Introduction, as mentioned above, is not the best option for beneficial insect populations to help manage pest populations in corn. We learned although alfalfa is a suitable habitat source of beneficial insect populations, an effort must be made to provide varying blossom colors to attract and promote continued and expanding population growth. The intermixing of various clovers seems appropriate.

We will continue this project in its current form to see if years can help build populations and attract other insect species. The other aspect we will implement is providing this type of habitat at all of our grassy areas and pivot points in our fields. It doesn’t seem cost effective to put strips through the field for a commercial grower. However, we believe changing the habitat surrounding our fields will be an addition no matter how small it may seem.

The advantages of this type of beneficial insect habitat and biological control system are the reduction of pesticides on the farm and potential for high control of all insect pests. The disadvantages are increased management through the alfalfa stripping, promotion of beneficial insect populations significant enough to do adequate control of pest insect populations, and income difference for not harvesting a sellable alfalfa product. These disadvantages may be offset with continued practice of and coordination of this system. The change in philosophy and management techniques takes time.

We have had many opportunities to talk with farmers regarding our project. Some responses have been favorable while others remain negative. This is to be expected and we are not discouraged by the negative. We will continue to work at implementing some type of beneficial insect habitat for promotion of these populations. We will continue to share our experiences and projects with those interested in listening.

OUTREACH
We told others about this project through the newspaper. Articles were written by Andy Christiansen highlighting the work done on our farm with the project. This sparked further newspaper coverage. The newspapers covering the project were the Aurora News-Register and the Grand Island Independent (at Husker Harvest Days time). Along with these, we have had tour groups out to visit and question the project and its directives. Dave received publicity from Acres USA for the project as well. These all promoted the questions that came from neighbors and others. We have spent countless hours talking through the project with people who are curious. This has been a positive aspect of the project we didn’t expect to see. All of the new coverage worked up the curiosity of farmers. It has been rather exciting to communicate a philosophy change for our operation and see other farmers work it through their own operations. We are all a very independent group of people who want to make a positive impact while making a living. This has appealed to many for this reason.