This project investigated and compared four Lepidoptera populations among three geographically diverse farms employing various reduced and conventional tillage techniques. The objective was to determine the influence of tillage on the Lepidoptera pest complex. Pheromone traps were placed within covered low tunnel cages where any emerging Lepidoptera moths in the field were trapped. The same sets of traps were placed outside of the covered tunnel cages in the field and along field edges. Traps were monitored weekly during emergence beginning in mid-April and continued through the first week of August. Moths were collected in pheromone traps directly outside of the covered tunnel cages as well as along field edges at farm sites. No moths were recovered within the covered tunnel cages on any tillage treatments at farm locations participating in this study.
In 2010, New York State fresh market sweet corn was grown on 23,500 acres and valued at $71.1 million while processing sweet corn, grown on 17,000 acres, was valued at $9 million. This makes sweet corn the most widely grown and valuable vegetable crop in NY. Reduced tillage has been adopted with much success on thousands of acres of sweet corn.
Growers recognize the advantages of reduced tillage including improvement of soil health, reduced labor and fuel costs, as well as marked increases in yields. Though the benefits of reduced tillage have been well demonstrated, questions have been raised concerning the effect of zone tillage on overwintering Lepidoptera populations of European corn borer (ECB), Black cut worm (BCW) and Corn ear worm (CEW) in sweet corn fields. ECB has traditionally been the major concern in sweet corn production, but has been fairly easy to control with well-timed, pyrethroid insecticides. In NY, ECB overwinters in fields where sweet corn and other susceptible vegetable crops are grown. To date, CEW has not been observed overwintering in NY but is believed to migrate into NY from southern states. In recent years, however, CEW is arriving about 6 weeks earlier and in much higher numbers. There is speculation that CEW may be overwintering in corn fields now. Cutworms are generally a sporadic problem on farms; some species overwinter while others migrate in.
Increasing Lepidoptera populations observed by some farmers using reduced tillage has given reason to suspect that there may be a relationship between reduced tillage and higher Lepidoptera populations. If this is the situation, reduced tillage may be increasing farmers’ reliance on insecticides and increase the number of sprays used. Furthermore, the perception by farmers that reduced tillage increases pest populations may be a barrier to the adoption of a beneficial soil management practice.
There is reason for concern as reduced tillage growers are not completely turning under crop residue by deep disking or mold board plowing fields, which may lead to Lepidoptera pests successfully overwintering in those fields. If reduced tillage systems are adversely influencing pest populations, growers may be required to make additional compulsory insecticide applications to maintain economically viable yield. This would reduce the savings and environmental benefits usually gained from reduced tillage systems.
The overarching objective of this project was to gather field based information to determine if fresh market sweet corn in Reduced-till systems is at greater risk to Lepidoptera pests. Through trapping and monitoring activities as described in the methods section below, we were able to:
1)investigate and compare four Lepidoptera populations, ECB E &amp; Z, BCW and CEW, among three geographically diverse farms employing various reduced and conventional tillage techniques
2) determine if ECB, CEW and cutworms overwintered in the field
3) determine the influence of tillage on the pest complex
In each treatment at farm A, B and C, a set of 3 (6 foot X 25 foot) low tunnel cages were erected using galvanized hoops( 72” W by 36” H) covered with Agribon row cover purchased through Tek Supply. ( See attached photos of set up). The farms and treatments were:
Farm A (Gill Farm, Hurley NY) we prepared 3 in-field treatments: each treatment area was approximately 3 acres.
? Treatment 1 (conventional tillage) Set up 4/30/12 , removed 7/27/12
? Treatment 2 (single cut)- ears of corn harvested, stalk left behind infield. In the Fall farmer seeds cover crop and discs in seed and stubble. In the spring the field is disced again and zone tilled. (This is how John Gill has been managing the Fields since 2008.) Set up 4/18/12, removed 7/17/12
? Treatment 3 (double cut) – ears harvested, stalks left in field. In the fall farmer discs first, then seeds cover crop, then discs again. In the spring the field is disked again and zone tilled. (the difference from treatment one is that the crop residue is disced in twice in the fall) Set up 4/30/12, removed 7/27/12
Farm B (Walkill View Farm-Peter Ferrante ), New Paltz, NY prepared 3 acres for project
? Treatment 1 (conventional tillage)- Field flooded during Hurricane Irene and Tropical storm Lee, entire unharvested stalks left in field. In the fall stalks disked and cover crop seeded. In spring plowed and disced. Set up 4/30/12, removed 7/27/12
Farm C (Altobelli Family Farms, Kinderhook, NY) will prepare 2 field treatments, 3 acres each.
? Treatment 1 (conventional tillage) Set up 4/30/12, removed 7/17/12
? Treatment 2 (reduced tillage) set up 5/18/12, removed 8/5/12
Low tunnel cages were placed in the field after the farmer seeded corn except for farm B where the farmer decided to not plant corn in 2012 and leave the field fallow for the season; he did plow and disc the field treatment area as he would if he were planting sweet corn before we put up the low tunnel cages. He planted sweet corn in adjacent fields. In each of the low tunnel covered cages, a set of pheromone traps were placed to capture emerging overwintering Lepidoptera moths, ECB-E, ECB-Z, CEW and BCW.
Sampling was conducted in an area with enough potentially infested corn stubble from the previous growing season. Each low tunnel cage covered an area that grew approximately 115 corn plants. For each treatment, the total area sampled equaled 450 ft.&#178;, containing a total plant population of 345 plants. The netted cages and traps were monitored weekly until the corn growing underneath got close to harvest and Lepidoptera emergence had completed. Moths of each species were counted and recorded.
At farms A&amp; B, at each treatment field, one set of pheromone traps were placed in the field outside of but close to the covered low tunnel cages. Farms A, B , and C, a set of pheromone traps were placed outside of the cages along the perimeter of the treatment fields to monitor for migratory or overwintering populations from weedy field edges.
In addition, a set of heliothis traps were placed at each farm to monitor overall farm ECB E and Z and CEW pressure.
Moth counts were monitored and recorded weekly. Pheromone lures were changed out every two weeks.
The data from each treatment on three different farms was compared and analyzed to determine if significantly higher numbers of overwintering Lepidoptera species occurred on reduced till field treatments.
We monitored for any occurrence of overwintering CEW as this has not been documented in NYS.
Data collected from the three farm sites and the various treatments suggests that ECB E, ECB Z, CEW, &amp; BCW, do not overwinter in the field in significant numbers. (See attached data sheets in Excel) No moths were trapped in any of the covered low tunnel cages regardless of the tillage treatment. At the same time, we did trap moths of all species in traps placed directly outside covered low tunnels. For ECB, these tended to be lower catches than in the traps placed in the weedy edges of fields especially at farm A. This suggests that the significant population of ECB is overwintering in weedy field edges on alternate hosts. It is likely that ECB emerge from the weedy field edges and then make their way to the sweet corn fields.
Comparing moth counts overall, across the tillage treatments; it does not appear from this study that reducing tillage influences Lepidoptera populations substantially. At Farm A and C where there were both reduced and conventional tillage treatments, we did not see a significant difference in moth counts among the treatments. Farm A consistently had higher moth counts for ECB in traps along weedy field edges regardless of the tillage treatment, suggesting this farm has a large refuge area to overwinter ECB.
As with the other Lepidoptera species, CEW was not recovered from within the covered low tunnel cages. It appears that they are not overwintering in the field in the Hudson Valley and are migrating in.
BCW was found only at farm A from traps placed outside of the covered low tunnel cages and weedy field edges where moth counts tended to be a bit higher. The weedy areas surrounding fields are likely providing refuge for this species as well as ECB.
The perception of some farmers that reduced tillage increases pest pressure can be a barrier to the adoption of the practice or influence a farmer to consider reverting back to conventional tillage as in the case of Farm A. This could prevent the farmer/farm from benefiting from the advantages of reduced tillage including improvement of soil health, reduced labor and fuel costs, as well as marked increases in yields.
Results from this study support that sweet corn grown in reduced tillage systems is not at greater risk to Lepidoptera pests, ECB E, ECB Z, CEW and BCW, than in a conventional tillage system.
Education & Outreach Activities and Participation Summary
Project presented at Vegetable Twilight Meeting held in Ulster County on July 12, 2012 and Capital District July 11, 2012. 52 growers participated.
January 24, 2013 – Power point presentation of project and results titled Overwintering Lepidoptera in Reduced Tillage System by Teresa Rusinek at the Sweet Corn session at the 2013 NYS Fruit and Veg EXPO in Syracuse. 102 session participants (see attached Power point)
Article titled Summary of SARE Study of Overwintering Corn Pests in Reduced Tillage Systems, written by Teresa Rusinek, published in Eastern New York Horticulture Newsletter Vol. 1, Issue 2 April 11, 2013. Distributed to growers throughout 17 counties in Eastern NY Hort program. ( see attached newsletter)
Areas needing additional study
Further investigation is warranted at the Gill Farm A in Hurley where populations of ECB E tend to be higher than other sweet corn farms in the area. Changes in weed management in areas bordering fields may help reduce ECB populations by eliminating refuge areas where ECB successfully overwinter.