- Fruits: pears, general tree fruits
- Crop Production: food product quality/safety
- Education and Training: demonstration, extension, farmer to farmer, on-farm/ranch research, participatory research
- Farm Business Management: risk management
- Pest Management: economic threshold, field monitoring/scouting, integrated pest management, physical control, prevention
- Production Systems: organic agriculture, transitioning to organic
The principle pests of pear production in the Northeastern US are pear psylla, Cacopsylla pyricola (Foerster), and Fabraea leaf spot, Fabraea maculata. These two pests cause premature defoliation, reduced fruit size, reduced quality and yield, premature decline and death of the tree. Insecticide resistance results in lower levels of efficacy, is reducing the effectiveness of currently used synthetic insecticides. Recent studies conducted at Cornell University’s Hudson Valley Laboratory have demonstrated excellent control of the pear psylla using newly developed OMRI products. These products, a kaolin clay based product called Surround WP and a highly refined horticultural oil (HRO) made by Petro Canada, PureSpray Green, were used successfully in pre-bloom and season long programs. IN previous years in research and commercial pear orchards we observed applications of HRO’s supress Fabraea leaf spotting, resulting in reduced defoliation.
Seasonal use of HRO’s in the Northeast for pear management beyond the delayed dormant stage of pear tree phenology has yet to be adopted in commercial orchards. In last years study on this topic we demonstrated the commercial effectiveness of this strategy, providing economically viable pest management and commercial grade fruit. In the second year of this study, Hudson Valley pear growers will augment commercial pest management tools with OMRI products. Growers will use cultural techniques of sucker removal to reduce the need for mid-season applications aimed at managing pear psylla that will provide open canopy for greater material coverage. Air induction nozzles will be compared to hollow disk nozzles to study the effects of off target drift. And to optimize material effectiveness we propose to evaluate sprayer calibration. Extension outreach to Northeast pear producers will include on-demand web based video vingettes of recommendations and text protocols for OMRI production methods, while oral presentations to the NYS pome fruit producer audience will be made at field meetings and winter fruit schools
Project objectives from proposal:
In 2007, the U.S. pear production was valued at 364 million dollars. New York is ranked fourth nationally in pear production with 1200 bearing acres and a crop valued at 5.1 million dollars (NASS-USDA 2007). New England including Connecticut valued their crop to be over 1.1 million dollars with 335 acres planted to pear (NASS-USDA 2006). Principal varieties of pear (Pyrus communis L.) grown in New York and New England are Bartlett and Bosc with increasing Asian and winter French varieties being planted on newly developed dwarfing rootstocks for earlier and increased yields.
The two primary pest obstacles limiting pear production prevalent throughout the northeast are pear psylla, Cacopsylla pyricola (Foerster), and Fabraea leaf spot, Fabraea maculata. The nymphal life stage is responsible for causing tree and fruit damage. This foliar feeding stage of pear psylla gives rise to five primary types of damage: leaf scorch, sooty mold development, fruit russet, psylla shock, and pear decline (Burts 1970, Agnello 1995). During the early instar stages of development the fragile young nymphs shunt excess sap called ‘honeydew’, encapsulating themselves with moisture to avoid desiccation. High sugar concentrations in the honewdew remain on the foliage causing leaf scorch. During heavy dew and rain the honeydew drips onto fruit causing fruit russetting, supporting growth of sooty mold fungi, and making fruit unmarketable. The 2nd generation of pear psylla causes the most severe damage to pear.
Fabraea leaf spot (FLS), Fabraea maculata, is of commercial importance in the mid-Atlantic region, the Hudson Valley of New York and the southern New England states. Fabraea leaf spot is a fungal pathogen that can cause mid-summer defoliation to susceptible cultivars including European varieties such as Bosc and Bartlett. Fruit infections result in cracked, misshapen, and disfigured fruit resulting in an unmarketable crop. EBDC fungicides, such as the mancozeb products, are most effective at controlling FLS. Mancozeb use must be discontinued 77 days prior to harvest, requiring the use of more costly late season strobilurin fungicide applications to maintain control of Fabraea during summer (Rosenberger 2008).
Additional pests of concern that require management include the plum curculio, Conotrachelus nenuphar (Herbst), pear leaf curl midge, Dasineura pyri, and the pear rust mite, Epitrimerus pyri. Secondary pests vary by locality and include the lepidopteran complex consisting of the codling moth, Cydia pomonella (L.), obliquebanded leafroller, Choristoneura rosacana (Harris), San Jose scale (SJS): Quadraspidiotus perniciosus, comstock mealybug, Pseudococcus comstocki, European red mite, Panonychus ulmi (Koch), and two spotted spider mite, Tetranychus urticae Koch.
Many of the older chemistries used for insect pest management in pear production systems have become ineffective due to insecticide resistance of the principle pear insect, pear psylla. This invasive species, introduced from Europe during the 1800’s, is endemic in commercial orchards, predisposing this pest to intense selective pressure for insecticide resistance with four generations each year. Newer reduced risk insecticides have recently been developed and are efficacious against pear psylla. Yet these newer insecticides are considerably more expensive. Most growers are making two to three applications per generation for pear psylla management, adding substantially to pest management costs. Pesticide drift to off target sites is a growing concern expressed by homeowners living adjacent to orchards. The use of HMO’s and Kaolin clay have not been shown to cause resistance in insect populations as their mechanism for control is primarily mechanical, while HMO’s being less susceptible to wind shear, maintain larger droplet size and so are inherently less likely to drift off target.
Over the past four years studies have been conducted at Cornell University’s Hudson Valley Laboratory and grower pear orchard blocks to determine the viability of Surround WP and HMO’s as synthetic insecticide replacements. We employed Organic Materials Review Institute (OMRI) approved pest management materials in both organic pest management strategies and as rotational materials to augment conventional pear psylla management programs 2. Studies using the kaolin clay product Surround WP (anhydrous aluminum silicate) proved to be very effective at controlling the 1st generation of pear psylla. Three early season applications of Surround WP followed by 5 late season oil applications was comparable to the most effective conventional treatments in research plot evaluations 3. Surround WP was also effective at controlling the early season fruit feeding insect complex when using dilute handgun applications. Season long applications of a 1% concentration of HMO’s demonstrate a significant reduction of both pear psylla oviposition and subsequent damage, reducing the incidence of Fabraea leaf spot. The use of summer oil has few negative impacts on fruit or foliage with damage to fruit appearing as slight russeting and raised lenticils. When leaf disks containing Fabraea lesions removed from oil-sprayed leaves 14 days after the preceding oil spray, spore release was reduced by 94% compared to Fabraea lesions of untreated control leaves. Spore germination was 63% lower for spores from oil-treated leaves compared to Fabraea lesions of untreated control leaves 4. HMO treated foliage and fruit showed reductions in fruit infection and a decrease in defoliation caused by Fabraea maculata. This is the first report that oil alone can provide commercial control of Fabraea leaf spot in seasons of moderate Fabraea pressure.
HMO’s employed during the season to gain control of pear psylla populations appear to be most effective when applied prior to the onset of egg laying and hatch for each of the four generations. Early season management using Surround WP, followed by HMO’s in the latter part of the season could be used successfully to produce organically grown pears in years of moderate to light Fabraea pressure. We will be employing Surround WP followed by HMO’s during this project in conventional programs to increase the efficacy of commercial pear pest management.
Experimental trials conducted on both apple and pear fruit have shown dramatically improved results of organic materials when applications are made using dilute volume rates above 200 gallons per acre with orchard tree row volume measuring 200 GPA or greater 5. However, in commercial orchards, conventional materials are successful using concentrate application rates of < 100 gallons per acre. For pear producers to achieve optimum results using organic materials such as Surround WP and HMO’s, growers will need to alternate between high and low volume sprayer output.
The use of air induction nozzles on sprayer systems reduce the pressure exerted on the liquid at the point of discharge, while reducing the percentage of fine droplets. Air induction nozzles use a venturi design to draw air into the nozzle body, incorporating the air droplets into the sprayed liquid droplets. This increases droplet size, and has been shown to reduce downwind particle drift significantly. In this study the use of air induction nozzles will be employed to increase deposition and reduce off-target drift of the airblast sprayer. Additional adjustments in calibration will be made to the sprayer by increasing output volume by increasing nozzle size. And decreasing sprayer travel speed will assist in optimizing spray coverage.
Comparing the combined cost of synthetic insecticides and fungicides to kaolin clay and oil used to manage Fabraea and pear psylla, may show these OMRI materials to be a less expensive alternative to the conventional synthetic insecticide / fungicide pear management programs.
Successful Fabraea management in commercial orchards begins shortly after bloom. It requires the use of bi-weekly manzate or strobilurin based fungicide program applied to susceptible European varieties. Given what we already know about the effectiveness of using oil for both pear psylla and Fabraea management, alternating the use of oil with a commercial fungicide on a bi-weekly program may provide optimum control of both psylla and Fabraea. Determining the appropriate application rate, timing and optimum number of applications required for each season is critical in obtaining optimum profitability levels. To reduce program costs to producers, we propose to limit the use of Surround WP to early season applications, followed by alternating HMO with synthetic fungicide applications for managing pear psylla and Fabraea through the remainder of the season. In so doing, materials costs can be restrained.
The rotation and or replacement of conventional pest management tools with HMO’s and Surround WP, coupled with shoot pruning, will serve to fulfill the ‘Tree Fruit IPM Stakeholder Research Priorities for New York State’. This priority is described as "Development and testing of alternative materials and non-pesticide options for pest and crop management" 6. HMO’s employed as insecticides have not been shown to promote resistance in insects due to their ‘mechanical’ mode of action, causing anoxia or smothering of the adult, egg and nymph stages.
[See summary of previous results in Documents attached: Tables 1-4; Hudson Valley Laboratory Plan Plot Map/Tables 5-8]
III. Project Methods:
1. Producers will use commercial application equipment with air induction nozzles to reduce off-target drift and increase deposition. Improving calibration to increase volume output, decrease speed and pump pressure, will improve material deposition resulting in superior efficacy.
2. Producers and researchers will determine the timing windows of OMRI materials using IPM scouting observations, weather forecasting and efficacious timings of prior studies. The successful results of this study will assist us in determining the number of applications, optimum timing and environmental conditions best suited to conventional and transitional organic pest management programs using OMRI materials.
3. Producers and researchers will consider costs, yield and quality to determine the economic factors of profitability using OMRI materials.
4. With the assistance of HVL research technical staff, producers will conduct shoot removal to reduce 2nd generation of pear psylla eggs and nymphs. This cultural practice, applied at the proper timing, will reduce damage to foliage and fruit during this ‘honeydew’ production period. Shoot removal will open the tree canopy for air and material movement during spray applications for greater material deposition.
5. Producers will become more familiar with CCE based computer information technology by viewing web-based extension publications and video throughout the season. These materials will be produced and made available to producers so as to obtain time sensitive information related to OMRI pear production methods.
Procedures: Two orchards will be used to evaluate the effectiveness of OMRI pest management materials to control pear psylla and Fabraea leaf spot on European pear varieties (Bartlett and Bosc). Increased deposition of materials will be achieved through proper calibration. Reduction of travel speed, increased volume output, use of air induction nozzles to both reduce off-target drift and increase droplet size, shoot removal of tree canopy to enhance material distribution throughout the tree canopy for better deposition will be conducted. Use of OMRI materials will be applied in season long pest management programs. They will be evaluated throughout the season and at harvest to determine insecticide and disease management effectiveness compared to commercial and untreated orchard blocks.
The LM Clarke Orchard will be divided into five sectors. Each sector will contain 4 replicates that transect across treated and untreated trees. Block 1 will contain a 2.5-acre block to which OMRI materials will be applied using air induction nozzles. Block 2 will contain a 2.5-acre block to which OMRI materials will be applied using hollow cone nozzles. Block 3 & 4 will contain two 5-acre blocks to which conventional materials will be applied using both air induction nozzles and hollow-cone nozzles. Block 5 will contain untreated trees. The one-acre HVL research pear orchard will have 7 dedicated comparison plots. Split plots of treatments of OMRI, OMRI / conventional treatments, conventional, and untreated plots will be replicated 4 times. Treatments will be applied using both dilute handgun and ‘simulated airblast’ handgun treatments with 300 and 100 GPA outputs respectively. Treatments at both sites will be applied at the same rates and timings, acting as replicates for purposes of statistical analysis.
Procedure 1. Through the use of air induction nozzles installed onto commercial application equipment, producers will reduce off target drift and increase material deposition. Grower concentrate airblast speed sprayer will receive 6 to 8 air induction nozzles mounted onto ‘flip over’ stems. These stems allow for the easy switching from air induction nozzles to conventional hollow cone disks at each nozzle position, seamlessly permitting the grower to flip nozzles to make the application of one material at two application rates in two distinct Blocks.
Evaluation: Analysis of foliage to determine coverage will be made during the white bud stage as foliage increases and expands. Leaf samples of 25 leaves will be removed from each plot, bagged, labeled, placed in coolers and brought back to the lab for computer scanning and deposition analysis using iVision software. Water sensitive cards will be stationed within 4-quadrants of the tree canopy, and at 5’ intervals leeward of the prevailing wind relative to the sprayer. Evaluation of deposition and drift using water sensitive cards will be conducted during white bud and three summer application dates beginning 1st cover (June 15th) , 3rd cover (July 15th) and 6th cover (August 15th). Cards will be labeled and brought back to the lab for computer scanning and deposition analysis using iVision software.
Procedure 2-3. Producers and researchers will determine the effectiveness of OMRI pest management materials in pear production. Applications of OMRI and conventional materials will be made for comparative purposes as described above. Data generated from the study taken from untreated treatments will be statistically analyzed to the OMRI and standard treatments. Treatments made to the HVL plots will employ a three point hitch mounted ‘Rears’ sprayer with high pressure handgun applications applied both dilute and ‘simulated airblast’ using a handgun to European varieties of Bosc and Bartlett in a randomized block design, using the same materials and same timing as the LM Clarke orchard.
Evaluations: Foliar and fruit evaluations of insecticidal and fungal efficacy is to be conducted throughout the season in each treatment including untreated controls of 4 replicates throughout blocks or plots. Pear psylla ovipositional data will be collected throughout the season beginning 1 March. 25 terminal cuttings containing 5 buds each will be pruned and bagged with the eggs deposited on buds followed counted using HVL dissecting scopes. Bi-weekly leaf samples of 25 leaves per treatment will be collected and evaluated for pear psylla nymphs and eggs. Foliage will also be rated at that timing for % infections of Fabraea beginning 1 June. Vacuum samples of adult pear psylla made using 3-minute foliage sweeps to determine adult presence will be conducted weekly beginning 1 March. Beginning the 15th June, trees in each block or plot will be rated for % defoliation. Harvest fruit evaluations will be conducted on 15 August for Bartlett and 1 September for Bosc at both sites. 100 fruit per treatment will be sampled and rated for % damage for all fruit feeding insects, Fabraea, sooty mold, russet, and phytotoxicity.
Yield and fruit weight measurements will be taken to determine plot and per acre yields. Percent clean and yield data will be combined to determine profitability curves for economic analysis.
Procedure 4: Shoot removal will be conducted in sub-plots of each treatment in both sites and data taken during foliar and fruit analysis partitioned to reflect plot distinctions.
Evaluations: Data from foliar and fruit collections partitioned to reflect differences in plots, collected as per Evaluation 2-3. Sucker removal costs to be incorporated into economic analysis with timed removal of suckers in ten representative trees.
Procedure 5: Producers will be trained to use a home computer to access to the Hudson Valley Regional Fruit Tree web site. Examples of video viewing, text access, and IPM scouting information will be presented with book marks of browser pages set for easy access.
Evaluations: Grower IP address will be recorded during grower presentation. Web site statistics will record times and dates of grow usage. Actual application timing will reflect web based timing recommendations.
V. Dissemination of Project Results: Extension outreach to Northeast pear producers will be available during oral presentations to the NYS pome fruit producer audience through pre-bloom and petal fall field meetings, held each year at the Fix Brothers Farm in Hudson, NY, and Crist Brothers Farm in Milton, NY. Yearly extension meetings at the Lake Champlain Tree Fruit School in Lake George, NY and Commercial Tree Fruit School in Kingston, NY, with over 300 eastern producers in attendance yearly, will be made in 20 minutes presentations.
Both literature and video will be available on-demand, available through the use of computer and internet access. Video vingettes, comprising 6 seasonal video clips of pome fruit production recommendations will be hosted on the Regional Tree Fruit web site (http://hudsonvf.cce.cornell.edu/scoutingreport.html). Samples of video recommendations produced in 2009 by the department of entomology at the HVL can be seen at (http://hudsonvf.cce.cornell.edu/photogallery.html ) under the video category. We will publish our final report in the form of a pdf file, hosted on the Hudson Valley Laboratory site (http://www.nysaes.cornell.edu/hudson/faculty.php), Cornell University faculty site (http://www.nysaes.cornell.edu/ent/faculty/jentsch/index.html#pro), and regional Hudson Valley Tree Fruit site (http://hudsonvf.cce.cornell.edu/scoutingreport.html). These data will also be accessible on demand by producers in the Pest Management Guidelines for Commercial Tree Fruit Production (http://ipmguidelines.org/TreeFruits/default.asp).