Determining the commercial viability of an exclusionary production system using disease-resistant columnar apple and sweet cherry cultivars

Determining the commercial viability of an exclusionary production system using disease-resistant columnar apple and sweet cherry cultivars

Summary

The project manager continued to develop 5 ‘exclusion’ sites (including 1 CSA farm (Community sponsored agriculture), 2 commercial farms, 1 historic farm, and one research site at Cornell's Hudson Valley Lab.). The disease-resistant apple trees using columnar architecture planted in a 30-degree v-trellis high-density system and dwarfing sweet cherry varieties on Gesila 6 rootstock were maintained for optimum growth in preparation for 2007 fruit production. The addition of wood chip mulches, weed removal, use of the drip irrigation, and development of the fixed-canopy spray system (HVL site only) were used to familiarize fruit growers with an integrated pest management system to protect against insect and vertebrate pests, hail and in the case of cherry, rainfall, without the use of synthetic and, in a replicated block design in a single site, without the use of organic pesticides. For a second successive year, the winter of 2006-07 was relatively mild compared to the winters of 2004-05, causing no apparent fruit tree injury or reduction of fruiting buds and developed flowers on apple and cherry throughout the Hudson Valley. Commercial crop estimates throughout the region were again very high for the second straight year. The period of pollination and mason bee release began on 2 May, lasted 12 days, with ample time and temperature for bee activity and fruit set. Fruit related evaluations were conducted throughout the 2007 season and initial estimates of fruit volume were promising given the numerous flowers of all four Stark varieties (Wijcik, Emerald Spire, Ultra Spire, Crimson Spire). The trees used in the project were in their 5th leaf this season and should have produced an abundant crop this year, Yet again, although commercial varieties had excellent crop loads, the Stark scab resistant varieties utilizing the columnar tree architecture did not produce a significant fruit quantity in 2007 to be economically viable. They did however increase in productivity from the previous year. This again seems to be a varietal response in the columnar trees we have chosen for the project. In all but the research site, there was no significant crop on any of the four varieties of apple in 2007. The cherry crop yielded a heavy crop across all four varieties (Attica, Benton, Regina, Sweetheart) with near drought conditions two weeks prior to harvest. Placement of netting to reduce insect and vertebrate damage to the cherry planting was added in spring 2007 and data to determine the efficacy of netting relative to non-netted plots was evaluated. For a third year we evaluated the degree of insect and disease pressure and efficacy of netting versus the non-netted plots as well as efficacy of organic pest management efficacy of the fixed spray system within the netting versus the non-netted plots. We evaluated weed presence using mulch treatments in the netted and un-netted plots while determing weed species and density. A new pomologist was added to the staff of Cornell’s Hudson Valley Lab as of September 2006. Steve Hoying, the new Horticultural Extension Associate yet due to staffing shortage and grape responsibilities was not able to assist in the project.

Objectives/Performance Targets

The exclusion production system continued to be developed on each of the 5 farms and research sites. Evaluation of weed presence in research plots, insect and disease presence on foliage and fruit, weather monitoring maintained to record environmental data, was conducted throughout the growing season. Overhead fixed spray system continued to be developed for canopy and fruit applications for both apple and cherry plots at the HVL site. Continuation of weed management through the application of weed barrier of composted chipped hardwood to limit weed plant competition for optimum tree growth. Continuation of use of the mason / blue orchard bee for pollination within netted plots for optimum fruit growth was conducted. Maintenance of plots including pruning for optimum fruit establishment was continued. Weather stations to monitor environmental conditions within exclusion plots compared to un-netted plot was continued. Incidence of insect fruit damage and foliar presence was determined through pre-June drop and harvest data collection. Data was analyzed and is presented in this report. Incidence of disease to fruit and foliage was determined through early-mid season data collection. Data was analyzed and presented in the final report. Summer 2007 Growers and researchers begin management protocols while making evaluations throughout the growing season. Researchers maintained detailed records and costs of inputs to conventional, IPM, and organic blocks while following exclusion management protocols. Pomology team was to conduct fruit tree trunk and canopy volume measurements for growth baseline initiated (Previous Pomologist committed to the project no longer resides at the HVL) Entomology team to continue ground cover management. Fall 2007 Year-end report to be sent to researchers, growers and NESARE. Write–up and analysis of data in each area of applicable study for year four. Expenditures for establishment and management of each system compiled. Fixed spray system evaluation for nutrient, irrigation and organic pesticide delivery.

Accomplishments/Milestones

Spring: A total of 110 cubic yards of composted wood chip was added to the 5 sites to maintain weed control. No additional nitrogen was required in 2007 as manure at planting and organic matter decomposition provided adequate supplies for the fourth growing season. A fixed nutrient, irrigation and spray system was functioning. An organic pesticide protocol was followed in both netted sprayed and un-netted sprayed plots in a complete replicated block design compared to netted and un-netted unsprayed plots. Complete evaluations of the four treatments was conducted. Summer: A grower tour of plots at the Hudson Valley Research Station was conducted on 7th of August in which over 30 regional fruit producers viewed the plots and were given information on the exclusion apple and cherry production system. Technical time spent on weed removal was maintained from the previous year as reduction in weed composition was accomplished through the use of yearly mulch applications. Application of mulch for weed management continues to be the greatest expenditure of time and consequently capital resources yet less time was required in 2007 due to earlier timing of mulch treatments. Insect, and disease data was collected and analyzed to evaluate the efficacy of the exclusion production system. The efficacy of the exclusion system for disease and insect management was less effective at managing the insect population than in 2006 , producing a higher level of damaged fruit than the un-netted sprayed plots and equal to the . Highest quality and number of marketable fruit were observed in the organically treated netted plots. The fixed spray system was evaluated for spray drift using spray sensitive cards. The system demonstrated significantly reduced drift on pesticide in both the netted and un-netted plots than the conventional orchard airblast applications. The netted spray system showing the least amount of pesticide drift. Fall: Phytophagous and predatory mite from foliar samples were analyzed in all plots to determine treatment effects on the mite complex and varietial preferences. Fruit from each variety and treatment were harvested and evaluated for insect and disease damage.

Impacts and Contributions/Outcomes

Elimination in the use of herbicides to manage weed competition through the use of wood chip mulch and elimination of fungicide applications for disease management through the use of disease resistant cultivars has dramatically reduced the number of chemical applications required for this system of fruit production. Elimination of chemical drift and thus worker exposure to pesticides are apparent advantages using this method of pest management. Yet costs for labor in weed management continue to offset any monetary savings that might have been realized in chemical and application reduction. Data from all plot evaluations in the following pages were taken to evaluated the efficacy of the fruiting varieties, insect exclusion system, organic applications within a fixed spray system and represent field means. The mean separation was performed by Fishers Protected LSD (P=<0.05). Treatment means followed by the same letter are not significantly different. The fixed spray system utilized both above and below ground delivery systems for insecticide, fungicide and herbicide applications. Overhead sprays delivering organic nutrient and pesticide to both apple and sweet cherry varieties with a herbicide delivery using fixed radial micro-sprinkler of a non-selective fatty acid based organic product 'Scythe' (pelargonic acid). Application rates of 5% v/v were made in 6 applications shortly after all plots had received mulch treatments beginning the 14th of May, 25th of May, 5th and 20th of June, 3rdand 17th of July. Weed evaluations were made in both cherry and apple plots. Weed observations were made in each plot, in the area that comprises the width of the mulch (3.5 feet) and under all eight trees, 2 each of four varieties, including 2 ft. beyond the first and last tree in each plot. This area ranged from approximately 16’ (56 sq ft) to 20’ (70 sq ft) in length depending on the two spacing designs. Through the plots 16 weed species were observed, including Weeds were observed in each plot in the area that comprises the width of the mulch (3.5 feet) and under all eight trees, 2 each of four varieties, including 2 ft. beyond the first and last tree in each plot. This area ranged from approximately 16’ to 20’ in length depending on the two spacing designs. Through the plots 16 weed species were observed, including Canada Thistle (Cirsium arvense), Chicory (Cichorium intybus), Common, Blue Violet (Viola papilionacea) , Creeping Buttercup (Ranunculus repens) , Dandelion (Taraxacum officinale) , Old Field Cinquefoil (Potentilla simplex) , Poison Ivy (Rhus radicans) , Quackgrass (Elytrigia repens), Red Sorrell (Rumex acetosella) , Virginia Creeper (Parthenocissus quiquefolia) , White Mulberry (Morus Alba) , Wild Buckwheat (Polygonum convolvus) , Wild Garlic (Allium vineale) , Wild Grape (Vitis rotundifolia) , Yellow Toad Flax (Lunaria vulgaris) and unidentified plant species. In apple receiving herbicide treatments we observed significantly lower numbers of plants, at 2.2 weed plant species per plot compared to untreated plots exhibiting 19.9 weed plant species per plot. Netted plots had fewer weed plant species per plot at 6.9 compared to Unnetted plots with 17.7, yet not statistically significant. The greatest number of weed plants were observed in unnetted plots with Canada Thistle (100 plants), Quackgrass (21 plants). The greatest diversity of plants developed in the netted plots including Quackgrass (29 plants), and the vines Virginia Creeper (4 plants)and Poison Ivy (15 plants). In cherry, we observed a greater diversity of plant species growing through the wood chip mulch.The treated cherry plots had 24.1 weed plants per plot compared to the wood chip only plots with 43.0 weed plants per plot. Netted plots had higher weed numbers in 2007, most likely due to the lack of netting in cherry plots in 2006. In netted plots we observed 43.9 weed plants per plot compared to 21.0 in the unnetted plots. We observed Quackgrass (78.8 plants / plot) to have the greatest abundant with Canada Thistle (59.0 plants), Red Sorrell (13.0 plants), Dandelion (4.7 plants), Wild Buckwheat (4.0 plants)of greatest abundance. The overhead spray system consists of ½” pvc tubing, overhead misting nozzles delivering 0.16 gpm (29.73 gpm per 6 treated plots in 371’ of linear row). Organic pesticide programs were initiated in both netted and un-netted plots in a complete replicated block design and consisted of 8 separate applications for control of plum curculio, leafroller complex, codling moth and the internal lep. Complex, stink bug complex, cherry and apple aphid complex, leafhopper complex, apple maggot. Treatment schedule: Sulfur at 18.0 lbs./A on 25 April, Sulfur at 18.0 lbs./A and Surround WP at 50 lbs./A on 7 May, 80% Sulfur at 18.0 lbs./A,Surround WP at 50 lbs./A, Aza-Direct at 48.0 oz./A, Dipel at 4.7 lbs./A on 14 May; Surround WP at 50 lbs./A, 80% Sulfur at 18.0 lbs./A, Aza-Direct at 48.0 oz./A and Entrust at 2.5 oz./A on 5 June; Sulfur at 18.0 lbs./A and Entrust at 2.5 oz./A on 20 June; Sulfur at 18.0 lbs./A, Entrust at 2.5 oz./A on 3 and 17 July. Secondary impact on both the phytophagous and predatory mite complex were observed in 2007 relative to both sprayed / unsprayed or netted / unnetted treatments. Foliar evaluations were conducted of the mite complex on all varieties throughout the netted/un-netted and sprayed/unsprayed matrix in 2006. A Log10 (X+1) transformation was applied to all mite data. The mean separation was performed by Fishers Protected LSD (P=<0.05). Treatment means followed by the same letter are not significantly different. All data represents field means. Mites were sampled by examining 25 terminals leaves per tree using mite brushing machine to remove mite onto soaped glass plates for evaluation under dissecting scope > 18x magnification. ERM = European red mite Panonychus ulmi; TSM = Two spotted spider mite Tetranychus urticae ; ZM = Zetzellia mali; (AMB): Neoseiulus (=Amblyseius) fallacies (Garman), ARM = apple rust mite Aculus schlechtendali. All mite data is displayed as # per 25 leaf sample. There were significant differences of mite found on treatments using the Emerald Spire but not between the four varieties. The ERM motiles and their eggs had highest numbers in sprayed plots of 14.3ab and 23.8b mite in the netted/sprayed and unnetted/sprayed plots respectively than in the netted/un-netted unsprayed plots, having only 1.0a mite respectively. . The ERM eggs also had highest numbers in sprayed plots of 14.7 b and 29.9 c mite in the netted/sprayed and unnetted/sprayed plots respectively than in the un-netted/netted unsprayed plots, having only 1.5a and 2.1a eggs respectively. The TSSM were evenly distributed throughout the plots ranging from 3.0 in the unnetted/sprayed plots to 9.9 in the netted unsprayed plots. The phytoseiid mite predator AMB was present throughout the plots with highest numbers in the unsprayed / netted plots (11.1 AMB), modest numbers in the netted and unnetted sprayed plots (8.1 and 9.7 respectively) and the unsprayed / unnetted plots having 1.8 AMB / plot. Again in 2007 we observed significant differences between the sprayed and unsprayed plots of the predatory mite ZM and its egg. The greatest difference was observed in the ZM in which equally high numbers were observed in the netted (10.7) and un-netted (17.3) unsprayed plots with very low numbers in the netted (2.0) and un-netted (1.3) sprayed plots. Sulfur appears to have greater negative impact on this biological control agent than on the phytoseiid population. Significant reductions in pest damage were again observed to foliage and fruit of apple within the exclusion plots this season. Significant differences between apple varieties for foliar damage were observed this season. Fruit evaluations were conducted of the insect complex on all varieties throughout the netted/un-netted and sprayed/unsprayed matrix. The mean separation was performed by Fishers Protected LSD (P=<0.05). Treatment means followed by the same letter are not significantly different. All data represents field means. Fruit were sampled by examining all fruit per variety per plot. Insects sampled were Apple maggot (AM): Rhagoletis pomonella (Walsh), European apple sawfly (EAS): Hoplocampa testudinea (Klug), Plum curculio (PC): Conotrachelus nenuphar (Herbst), Green fruitworm (GFW): Lithophane antennata (Walker), Obliquebanded leafroller (OBLR): Choristoneura rosaceana (Harris), Redbanded leafroller (RBLR): Argyrotaenia velutinana (Walker), Tarnished plant bug (TPB): Lygus lineolaris (P. de B.), Codling moth (CM): Cydia pomonella (Linnaeus), Lesser apple worm (LAW): Grapholita prunivora Walsh, Oriental fruit moth (OFM): Grapholitha molesta (Busck), Stink bug complex (SB): Green stink bug, Acrosternum hilare (Say); brown stink bug, Euschistus servus (Say).The final report will include extensive fruit damage ratings to both cherry and apple varieties. The four apple varieties we’ve chosen within the study parameters are disease resistant dwarfing columnar varieties commercially available through Stark Brothers that include the Stark ‘Ultra’, ‘Crimson’ ‘Emerald’ and ‘Wijick’ variety. As stated earlier we found relatively high levels of flowers / tree. The number of fruit per tree of each variety was again lower than expected. We observed mean fruit numbers in 2007 of 8.3, 8.0, and 9.4 and 2.6 fruit per tree in Stark ‘Ultra’, ‘Crimson’, ‘Emerald’ and ‘Wijick’ respectively. Although these numbers seem low the spacing of these trees on two spacing dimensions (12” and 18” tree spacing) with 16’ drive rows, represent 2722 and 1815 trees per acre respectively. Using our 2007 harvest data (and assuming 100% clean fruit within the exclusion system) we calculate a harvest of 22.7, 515.9, 115.5 and 1.4 bushel on 12” spacing, and 15.1, 344.0, 77.0 and 0.9 bushel on 18” spacing of ‘Ultra’, ‘Crimson’ and ‘Emerald’ respectively. The volume of high-density commercially grown fruit grown throughout the Hudson Valley will range from 500 to 1200 bushels per acre on any given orchard in any given year. The dwarfing disease resistant varieties used in this project appear to fall well below the range of acceptable per acre harvest volume of apple when grown at either spacing within a insect exclusion system. The price of orchard run fruit (Empire or McIntosh) averages $8.00 per bushel. If we apply this value to the exclusion system of the most productive variety (‘Crimson’), we estimate gross returns at $4,127.10 in 12” tree spacing and $2,751.90 in 18” spacing.