Integrated Phytophthora blight management in vegetable crops with enhanced soil health from cover crops, reduced tillage, and brassica biofumigation

Integrated Phytophthora blight management in vegetable crops with enhanced soil health from cover crops, reduced tillage, and brassica biofumigation

Summary

The crop disease Phytophthora blight (PB) is a top concern for vegetable growers in the northeast (including the northeastern Midwest) where susceptible cucurbit and nightshade species of crops contribute to major portions of farm incomes and to the greater vegetable industry. Soil health improvement has been proposed as a fundamental component of an integrated PB management program. Certain brassica cover crops are capable of providing biofumigation services to soils with high soil-borne pathogen loads, and reduced tillage can allow for soils to regenerate functions that further mitigate soil borne disease. This project is aimed at increasing grower awareness and adoption of integrated PB management through demonstration and research trials that incorporate novel components 1) of biofumigation with brassica cover crops and 2) reduced tillage on six NY farms and at Cornell’s Long Island Horticultural Research and Extension Center (LIHREC).

Between August 2014 and March 2015, the project team was able to recruit six growers (two tentative) to collaborate in our on-farm research component. Four growers established on-farm trials in the fall (Fig. 1) with winter brassica biofumigation cover crops (‘Nemat’ arugula) compared to their standard overwinter practice (cereal rye or fallow). Two other growers plan on planting a spring biofumigant variety (‘Caliente 199’) in April 2015 (along with two others that also planted a winter variety). Plot-scale trials have also begun at the LIHREC where the fall-planted treatments are currently established. To date, the project team already has spoken to researchers outside NY in the greater Great Lakes region about the project, and to >110 growers about biofumigation, reduced tillage, and an integrated PB management approach since the project began. Four other growers besides the core six farmer colaborators are also trialing biofumigation in 2015 as a result of this project (Fig. 2). 

• Fig 2. ‘Nemat’ arugula biofumigation cover crop being infomally trialed by Hudson Valley grower in bed system
• Fig. 1) ‘Nemat’ arugula biofumigation cover crop adjacent to cereal rye at on-farm research site, Hudson Valley

Objectives/Performance Targets

Forty vegetable growers across three regions of NY will integrate multiple soil borne disease management practices that may include biofumigation with brassica cover crops and reduced tillage on at least an 5 acres per farm, recovering $1000 – $4000 per acre otherwise spent and/or lost on diseases like Phytophthora blight.

Accomplishments/Milestones

1) 6 growers battling PB in three distinct regions of NY are recruited by Extension and guided through the process of choosing treatments and establishing a trial including a brassica cover crop for biofumigation and reduced tillage. September 2014 – April 2015. Milestone 66% complete as of March 2015. Four of six recruited growers have winter biofumigant varieties planted for trials (Fig 1). Two growers who chose to plant spring varieties have not planted yet. Planting and milestone completion anticipated by April 2015.

2) 75 growers attend field days (25/region) and learn about PB and integrated approaches to managing PB and soil-borne diseases through viewing trials and from the project’s grower collaborators and research team. June 2015. The project team is ahead of schedule on a portion of this milestone, having already spoken to at least 110 growers in NY about the project components.

3) 300 growers total attending winter conference/meeting presentations will learn about integrated approaches to managing PB and soil-borne diseases and year 1 trial results. January-March 2016. The project team is ahead of schedule on a portion of this milestone, having already spoken to at least 110 growers in NY about the project components.

4) 75 growers attend field days (25/region) and learn about PB and integrated approaches to managing PB and soil-borne diseases through viewing trials and from the project’s grower collaborators and research team. June 2016.

5) 300 growers total attending winter conference/meeting presentations will learn about integrated approaches to managing PB and soil-borne diseases and project results. January-March 2017.

6) 1500 beneficiaries total nationally will learn about our biofumigation with brassica cover crops and integrated approaches to managing PB and soil-borne diseases via the above contacts, and Extension materials posted online, a webinar, and an instructional video. Ongoing until September 2017. The project team is ahead of schedule on a portion of this milestone, with one collaborator having spoken to researchers in the greater Great Lakes region (including Canada) about the project components.

7) 40 growers in three distinct regions of NY (10-15/region) are mentored by our grower collaborators and/or Extension in implementing integrated approaches to PB and/or soil-borne disease management in each respective region represented in the project. Ongoing until September 2017. The project team is ahead of schedule on a portion of this milestone, with four other growers in addition to the six formal core collaborators trialing biofumigation cover crops in 2015 under the guidance of Extension (Fig.2).

Impacts and Contributions/Outcomes

Prior to the project start date, the P.I., O’Dea, visited project team collaborators in both of their respective regions in summer of 2014 to meet with area growers and to discuss research plans for the project. In June 2014, O’Dea and collaborators Menasha and McGrath met in Long Island (Suffolk County) and visited with four different area growers battling PB to discuss the project; each grower expressed interest in the research, and particularly the use of brassica cover crops. Growers that had grown brassica cover crops before perceived general positive effects on subsequent cash crop yields and were further interested in quantifying the impact of their use in mitigating PB. Favor for the reduced tillage aspect was present for some growers, but less ubiquitous. One grower expressed earnest interest to be a grower collaborator for the on-farm trials in spring 2015. Research plans for the plot scale trials at the LIHREC were also discussed; research plans remain mostly unchanged, but due to spatial complications, the research team agreed to lower the number of replications from six to four. The research plot area was also increased to encompass a 6-acre area (previously 3.4 acres).

In August 2014, O’Dea met with collaborator Hadad and visited two growers battling PB in far western NY (Erie County). Each grower expressed interest in expanding the number of tools available to them for managing PB. Similar to Long Island, again, the core of the interest was in using brassica cover crops, but growers in this region expressed crop rotation concerns (disease risk concerns) because brassica cash crops are common in this region. Western NY growers were also more unsure of the reduced tillage aspect; reduced tillage in this region is less widely adopted than in Long Island, and growers were unfamiliar with the practice and lacked equipment. One grower agreed to participate in the project, and another regional Extension agent was able to make a connection that will allow for reduced tillage equipment to be borrowed for the second year of trials in this region. O’Dea was also abke to attend a grower twilight meeting that day on vegetable diseases (including PB), where O’Dea and Hadad were given the opportunity to explain the upcoming project to an audience of ~22 area growers.

In August, O’Dea recruited two areas growers to participate in the on-farm trials. Both growers agreed to trial both winter and spring biofumigation varieties; one of the two growers owns reduced tillage equipment, and has agreed to provide the service to the other participating grower for the second trial year. Trials at each site were established at each site in mid-September with a winter variety, ‘Nemat’ arugula, planted adjacent to plots of winter rye (Fig. 1). There was extra arugula seed to spare after the trials were planted, so remaining seed was given out to four other Hudson Valley farms eager to trial the biofumigants informally in small plots (Fig.1); all planted by the end of September. The informal trials also provide an opportunity for an observational assessment of cover crop performace on differnt farms, soils, and planting dates. An early observation of the arugula was variability in plant vigor due to an apparent strong response to available nutrient levels that varied across different soils. O’Dea also had the opportunity to explain the project at an Extension grower twilight meeting in the Hudson Valley in July to ~30 participants including area growers and extension specialists.

Collaborator Hadad was able to find two collaborators in western NY that planted Nemat arugula by late September for the on-farm research trials. Hadad was also able to speak to western NY growers (~33 participants) and Great Lakes region researchers (including Canadian researchers) at two separate meetings in February; both growers and researchers expressed eagerness to hear the results of the project due to their respective concerns about the impact of PB. Another grower working group in western NY met this winter and listed PB as one of the top 5 concerns for vegetable growers.

Collaborators Menasha and McGrath successfully planted plots of ‘Nemat’ arugula, ‘Nemat’ arugula + Dutch white clover, and rye control plots this past fall at the LIHREC. The spring biofumigant varieties will be sown in April, and winter squash will be grown as the response cash crop across all treatments in the coming year. Menasha has tentatively secured two grower collaborators that will be planting spring biofumigant varieties for the on-farm trials. Menasha has been mentioning the project and biofumigation as part of an integrated PB management program in one-on-one consultations with 14 interested area growers to date.

Collaborators: