Implementing biointensive pest management and evaluating hard cider manufacturing to increase sustainability of apple production
In 2008, field experiments showed that IPM protocols designed for a scab-resistant apple orchard resulted in fewer pesticide sprays, lower input costs, higher returns, and a lower Field Environmental Impact Quotient rating than either conventional IPM or a traditional calendar-based pesticide-spray schedule, and that using composted hardwood chips as mulch suppressed weed biomass and reduced reliance on chemical herbicides in tree-row strips while conserving soil moisture, reducing soil temperature, and increasing soil organic matter and nitrogen. Experiments to produce hard cider from Iowa apples continued to refine methodology and blends to develop products that consumers would prefer over national brands currently on the market. On-farm demonstration trials with six commercial apple growers in Iowa added to the project’s evidence that the Brown-Sutton-Hartman warning system for sooty blotch and flyspeck saves 1 to 2 fungicide sprays per season compared to conventional calendar-based spraying without compromising control of this disease, and that volume of first- and second-cover fungicide sprays did not impact performance of the warning system.
Objective 1. Compare innovative tactics to conventional IPM and traditional practices for disease, insect, and weed management in annual field trials.
Producing apples in the Midwest requires intensive, chemically based pest management systems in order to bring high-quality, fresh market apples to consumers. A combination of rising costs, pest resistance, and new legislation has caused existing systems of apple pest management to become ineffective or to fall out of favor with growers. Because of this, new methods of pest control were developed to combat the ever present problems in apple production. These new methods must meet a number of criteria: sufficient pest control must be achieved, the innovative tactics must be safer for applicators, the environment, and consumers, and must also be economically feasible or they are not likely to be adopted by growers.
Utilization of disease-resistant apple cultivars can reduce dependency on fungicide spraying, cut input costs, and improve profits. Several cultivars with excellent resistance to apple scab and other diseases (rusts, fire blight, and powdery mildew) are on the market and have produced excellent yield and eating quality. To incorporate these cultivars into apple production in the Midwest, one of the challenges is to develop IPM strategies customized to the disease-resistant abilites of these cultivars. The aim of field experiment reported here is to find efficient and effective disease and pest management strategies for these cultivars.
The field experiment had two aspects in the same field plot, separately evaluating: A) disease and insect pest management methods and B) use of mulch for weed management and soil improvement.
A) Disease and insect pest management trials
Materials and Methods
In 2008, the 2nd year of a 3-year study, a conventional apple pest management system was compared to a current integrated pest management (IPM) and two new IPM systems employing a combination of pest control tactics. These included three apple scab-resistant cultivars (Redfree, Liberty, and Gold Rush) on M9 rootstock, a weather-based disease warning system for sooty blotch and flyspeck called the Brown-Sutton-Hartman system, and alternative, reduced-risk pesticides.
Four apple pest management treatments were compared in a 5-year-old orchard at the ISU Horticulture Farm near Gilbert, IA. The plot was arranged in a stratified randomized complete block with 5 blocks for each treatment-cultivar combination and 5 trees per subplot. Treatments were: 1. Calendar-based (traditional) spray timing using conventional pesticides; 2. Current IPM, omitting the first springtime fungicide spray, and utilizing degree-day models for timing insecticide sprays against codling moth; 3. New IPM A, omitting the first two springtime fungicide sprays, using the Brown-Sutton-Hartman warning system for SBFS (based on cumulative hours of leaf wetness after the first-cover fungicide spray has been applied) and reduced-risk insecticides applied on a calendar-based schedule; and 4. New IPM B, using a variation of the SBFS warning system that substitutes hours of relative humidity >97% for leaf wetness hours, and reduced-risk insecticide sprays timed by degree days and insect trap captures.
At harvest, mean percentage of fruit with SBFS, apple scab, codling moth, and damage due to other insects and disease were recorded for each fruit. Marketable and cull apples were also counted and weighed.
Results and Discussion
In 2008, there were very few differences in marketable or cull number and weight of apples among treatments, and very few differences among treatments for insect and disease incidence. No apple scab appeared; this was expected due to the cultivars’ resistance to that disease. No SBFS signs appeared on early cultivar Redfree and few signs were observed on later-harvested cultivars. Treatments using SBFS warning systems had slightly more SBFS signs than conventional treatments, but still had <1% incidence on fruit. Very little codling moth damage occurred. Treatment 4 required the fewest pesticide sprays to manage pests and diseases. Treatment 3 required weekly Cyd-X applications throughout the growing season and spray numbers were higher than any other treatment. Several of the new IPM options explored in this study controlled apple pests as well as conventional strategies and showed potential for reducing orchard management costs while minimizing pesticide exposure to humans and the environment.
Ecological risk rating of pest management treatments. Treatments in 2007 and 2008 were assigned values, on a rating scale called the Field Environmental Impact Quotient (FEIQ), indicating ecological risks as outlined in Kovach et al. (1992). As new pesticides were introduced and formulations changed, point values were updated (Kovach, 1992). The point value for each pesticide is proportionate to the ecological risk associated with its use. Total risk for each treatment was determined for each cultivar using the sum of FEIQs for each pesticide used in the treatment. FEIQ for each pesticide was determined by the following equation: (EIQ) x (percent active ingredient) x (dose/hectare) x (number of applications) (Kovach, 1992). Codling moth (Cydia pomonella) granulovirus (CydX®) was not assigned a rating in previous studies, so an EIQ value (6.7) was developed based the same parameters used by Kovach et al. (1992).
New IPM Treatments 3 and 4 had substantially lower ecological risk than calendar-based spraying (Treatment 1) and conventional IPM (Treatment 2) using the Field EIQ system. In 2007, New IPM treatments scored >40 % lower than calendar-based and >30 % lower than conventional IPM for cultivar ‘Redfree,’ while New IPM treatments showed nearly 50 % less ecological risk than calendar-based spraying for cultivar ‘Goldrush.’ In 2008, in part because early-season spraying differed from 2007, New IPM B (Treatment 4) scored nearly 75, 70, and 70 % lower for cultivars ‘Redfree,’ ‘Liberty,’ and ‘Goldrush,’ respectively, than calendar-based spraying (Treatment 1).
Summary. These preliminary results indicate that the new IPM tactics under trial in this experiment are likely to be considerably more environmentally sustainable than conventional IPM or traditional, calendar-based pesticide-spray programs.
B) Mulching for weed management and soil improvement
In 2006-2008, mulching was compared to a bare-ground control in five replications; each subplot consisted of a five-tree row segment. Within each replication, the same cultivar was used for mulched and bare-ground subplots. Mulched subplots received a 15-cm-deep layer of composted hardwood mulch (Source: All Seasons Mulch, Ames, IA) in a 2-m-wide strip beneath the tree canopy in June 2006 and June 2008. The mulch had been composted for at least 1 year before use. A mulch-free zone was maintained within a 30-cm radius of tree trunks.
Two-meter-wide strips beneath the canopy were maintained free of weeds from the beginning of May until the beginning of July. An initial herbicide application was made at the beginning of each season to both bare-ground and mulched subplots. Herbicide sprays were applied using a boom sprayer when the tallest weeds had reached 12.5 cm in height. After mid-July, weeds were controlled by periodic mowing. Table 6 in the Appendix summarizes the products, rates, and timing of weed management tactics utilized in this study, and amount of pesticide active ingredient used each spray.
In 2007 and 2008, soil temperature was measured at 5-and 10-cm depths in one subplot of each bare-ground and mulched soil treatment using thermistors (Model 107, Campbell Scientific, Logan, UT). Soil volumetric water content was measured at depths of 0 to 15 cm and 15 to 30 cm using TDR sensors (Model CS616, Campbell Scientific).
A baseline soil chemical test was performed on 19 July 2006 and in mid-July 2007 and 2008. Two samples were collected from each bare-ground and mulched subplot. The first sample was a composite of five soil cores beneath each tree in a five-tree segment from of 0 to 15 cm depth, and the second sample was from a depth of 15 to 30 cm.
Soil samples were submitted to the Iowa State University Soil and Plant Analysis Laboratory (Ames, IA) and tested for percent organic matter and nitrogen.
Before bud break in 2007 and 2008, growth was assessed for the center three trees in each subplot. Trunk diameter was measured 15 cm above the graft union. Tree height and limb spread from north to south were recorded before bud break in mid-March of 2007 and 2008 using a measuring tape.
Weed species data was collected monthly from May to September of 2007 and 2008 along 13 transects per subplot, yielding 130 data points per subplot. At each point, presence or absence of weeds was noted; if present, the tallest weed was identified to species.
Weed biomass was assessed in early August of 2006, and early September of 2007 and 2008 using 0.1 m2 quadrat that was placed randomly at five locations in each subplot. Weeds harvested from five subsamples in each subplot were combined, oven-dried for 3 days at 65° C, and weighed.
In 2006, weed cover was analyzed using PROC GLM ANOVA for randomized complete block designs. In 2007 and 2008, data were analyzed using a repeated measures technique using the PROC MIXED procedure and the Tukey-Kramer adjustment for a randomized complete block design. Weed biomass data were analyzed using PROC GLM ANOVA for randomized complete block designs. Tree vigor, soil chemical properties, and leaf nutrient data were analyzed with an ANOVA using the mixed procedure in SAS for randomized complete block designs.
Results and Discussion
Weeds. Mulched plots required spot treatments of herbicide throughout the season to manage localized outbreaks of weeds, but bare-ground plots required herbicide applications over the entire ground surface. Mulched plots required approximately 20 and 25 % less herbicide than bare ground plots in 2007 and 2008, respectively. Mulched plots had significantly less weed coverage than bare-ground plots on more than half the sampling dates, usually late in the growing season. In July of 2007, common purslane (Portulaca oleracea) covered nearly 50% of sampling points in bare-ground plots, whereas none was found in mulched plots. Common purslane continued to appear in bare-ground plots in higher amounts than mulched plots for the rest of the season in 2007 and in 2008. In contrast, barnyard grass (Echinochloa crus-galli) covered significantly more of the mulched than bare-ground subplots in July, August, and September of 2007, and June of 2008.
Mean weed biomass was significantly lower in mulched than bare-ground plots all three field seasons. Differences were most notable in August 2006, when weed biomass in bare-ground plots was nearly 250 g/m2 and mulched plots had < 50 g/m2.
Trunk diameter, tree height, and limb spread did not differ significantly for trees in bare-ground and mulched plots in 2007 or 2008. Limb spread was less in 2008 than 2007 because of winter pruning which occurred in December of 2007.
Average weekly soil temperatures beneath bare ground fluctuated more than temperatures beneath mulched plots. Soil temperatures remained cooler under mulch, usually by at least 2° C, until near the end of the growing season, when the difference began to narrow.
Volumetric water content beneath mulched plots at 15- and 30-cm depths was higher than under bare-ground plots throughout most of the season. In 2007, volumetric water content was generally higher at a depth of 30 cm than at 15 cm in mulched plots. Mean soil nutrient levels, organic matter, and pH varied widely among bare-ground and mulched plots in all three years. Total percent carbon, nitrogen, and organic matter were nearly identical between treatments in 2006, but in 2007 they all increased in mulched relative to bare-ground plots, and these differences were statistically significant in 2008.
Objective 2: Develop methods for producing hard apple cider of consistently high quality that Midwest consumers are willing to buy.
Materials and methods
‘Golden Delicious’ and ‘Jonathan’ apples were grown at the Iowa State University Horticulture Farm and ‘MacIntosh’ and ‘Chieftain’ apples were grown at Deal’s Orchard, Jefferson, IA. Apples were pressed, juice was fermented, and cider was bottled by Dr. Lester Wilson in the Center for Crops Utilization Research, ISU, in February 2008. Cider was stored at refrigeration temperature until sensory evaluation in February and March 2008.
A 9-member trained sensory panel evaluated the sensory characteristics of the hard apple ciders. Panelists were selected from students and faculty in the Department of Food Science and Human Nutrition, ISU. Panelists attended one-hour training sessions, twice a week for five weeks to become familiar with the characteristics of hard ciders. Panelists evaluated the attributes of commercial hard ciders and other apple products. Commercial products included K, Woodpecker, Hardcore, Hornsby’sPanelists determined the following characteristics and references for use on a 15-cm linescale from 0 = none to 15= intense.
After training, panelists evaluated the 4 ciders on 3 separate days (3 replications) in separate booths under fluorescent lights in the Human Nutritional Sciences Bldg, ISU. Data were analyzed by analysis of variance and Tukey’s HSD multiple comparison test was used to determine mean separation.
Soluble solids of the ciders was measured by using a Reichert AR200 Digital Handheld Refractometer. A HunterLab MiniScan® XE Plus was used to determine the color of each sample.
Results and Discussion
Hard apple ciders were not different in apple aroma. Apple cider made from ‘Chieftan’ and ‘Golden Delicious’ apples had more intense alcoholic aroma than cider made from ‘MacIntosh’ apples. Cider from ‘MacIntosh’ apples was less effervescent, lighter in color, more sweet, with more apple flavor, but less sourness and astringency than ‘Chieftan’, ‘Golden Delicious’, and ‘Jonathan” ciders. ‘MacIntosh” cider was lighter (higher L-value) than ‘Chieftan’ cider, but similar to ciders made from ‘Golden Delicious’ and ‘Jonathan’ apples. Sensory panelists also reported that ‘Chieftan’ cider was darker amber color than all other ciders.
‘Jonathan’ cider was sweeter than ‘Chieftan’ cider, but similar to cider made from ‘Golden Delicious’ apples. Cider from ‘Golden Delicious’ apples had more intense apple flavor than ‘Jonathan’ cider, but was similar to ‘Chieftan’ cider. All ciders except ‘MacIntosh’ were similar in sourness and astringency.
Soluble solids contents were not different because all ciders were formulated to be similar in sugar content.
Cloudiness and effervescence varied, depending on bottle within cultivar, due to differences in production. All panelists received samples from the same bottle. Separate bottles were served at each replication/evaluation date. All ciders were adjusted to 7% soluble solids.
The following comments were made by panelists about the attributes of hard apple ciders. These are editorial comments and not part of the analysis. Cider made from ‘Chieftain’ apples had a pleasant fruit and champagne aroma. ‘MacIntosh’ cider had low champagne aroma and mild apple/fruity odor. ‘Golden Delicious’ cider had a strong wine/champagne odor; a low fruity aroma that may have been masked by the wine odor. ‘Jonathan’ cider had low champagne/wine odor and a mild fruity aroma.
‘MacIntosh’ cider had a good effervescence compared to the standard. ‘Golden Delicious’ cider had a good effervescence and a good presence of bubbles in the tongue. ‘Jonathan’ cider was mildly effervescent. ‘Chieftan’ cider had low effervescence compared to the standard, but contained lots of bubbles.
‘Chieftain’ cider had good apple cider color, but was slightly cloudy/turbid which detracted from appearance. ‘MacIntosh’ cider was clear and had good champagne color. ‘Golden Delicious’ cider had low color, appropriate for champagne color, but slight turbidity detracted from appearance. Jonathan had a low color like champagne but cloudy.
‘MacIntosh’ cider was the best tasting of all four samples. This cider had a pleasant taste, good level of sweetness, a good mild apple/fruity flavor, low acid and the lowest astringency. ‘Chieftan’ and ‘Golden Delicious’ ciders were hard to detect sweetness and apple flavor because the sour and astringency taste was stronger. Cider from ‘Jonathan’ apples had acceptable levels of sweetness, masked slightly by alcohol, low sourness and astringency but pleasant.
Andress, E., Harrison, J. 2003. Making apple cider (Online). Research on March 13, 2008. http://www.fcs.uga.edu/pubs/PDF/FDNS-E-91.pdf
Research on April 3, 2008. http://www.applejournal.com/art001b.htm
Matvienko, et al. 2000. Iowa-grown apples (Online). Research on April 3, 2008. http://www.extension.iastate.edu/Publications/PM1863.pdf
Nine panelists evaluated 2 blends of hard apple cider on March 14, 2008, using the same evaluation scorecard and references. One replication was completed; analysis of variance was completed using 2 treatments and 9 panelists (9 replications).
letters are significantly different, p<0.05, NS=not significant.
Recommendations for 2009:
1. Produce cider from same cultivars
2. Use internal standard of a commercial apple cider (‘K’ recommended as highest quality and similar to ISU hard cider)
3. Determine data needed from cider blends.
Objective 3. a) Calculate the costs, benefits, and risks of the alternative apple management systems in Objective 1; b) Estimate the costs, benefits, and risks associated with local-scale manufacturing and marketing of hard cider in Iowa.
Materials and Methods
A partial budget, calculated from results of the canopy pest trials in 2008, was used to compare the cost and revenue of pest management strategies (26). To assess possible economies of scale, partial budgets were projected for orchard sizes of 0.4, 2.0, 4.0, 8.1, and 16.2 ha (16). In 2007, only treatment costs were determined.
Costs of pesticides were obtained from United Agri Products and FMC Corporation, two commercial pesticide suppliers in the Midwest, during November of 2007 and May of 2008. Additional pesticide prices were estimated from a price sheet for Maine apple growers (28) and the North Dakota Field Crop Insect Management Guide (27).
Tractor and sprayer prices were estimated using an enterprise budget for medium density orchards (44). Machinery costs per hour reflected both variable and fixed costs. Variable costs included fuel, lubrication, and repairs and maintenance. Fixed costs included depreciation, interest, and insurance. A new four-wheel drive, 70 horsepower tractor cost $31.58 per hour. A new 400-gallon, power takeoff driven airblast sprayer cost $23.44 per hour. Total equipment cost was $66.02 per hour which includes an $11.00 per hour wage for a machinery operator (13).
Spray time in a commercial orchard was determined by consulting several apple producers and research horticulturists. Spray time was estimated at 20 minutes per 0.4 ha (Lynn Schroeder, Iowa State University Horticulturist, personal communication; Greg Baedke, Community Orchard, Fort Dodge, IA, personal communication). Spray preparation time was estimated to be 15 minutes, and clean-up was estimated as 30 minutes. Clean-up times were assumed to be the same for all orchard sizes. However, multiple mixing times were required for larger orchards because the sprayer needed to be filled several times.
Weather-monitoring equipment was assumed to have a 5-yr lifetime, with an amortization rate of 20 percent (Cynthia Turski, Spectrum Technologies Inc., Plainview, IL, personal communication). Although the number of required codling moth traps increased for larger orchards, only one datalogger and thermograph were required for all orchard sizes examined.
At harvest, the number of marketable and cull fruit were counted and weighed for trees in each treatment. Apples were graded and separated as 8.1 cm in diameter. Yield data were recorded from the middle three trees of each five-tree subplot in 2006 and 2008, and from all five trees per subplot in 2007.
Returns of $3.31 per kilogram were assumed for all cultivars, based on a May 2008 telephone survey of prices which local Iowa growers said they received for fresh market apples. Price per kilogram was applied to average yield per tree in 2008. Average yield per tree was then multiplied by the number of trees per hectare (727). To calculate net returns, production costs (pesticides, machinery, monitoring equipment, spraying and scouting labor) were subtracted from the total fresh market value of fruit.
Per hectare cost of pest management in 2008 was highest for Treatment 3 at all orchard sizes because of weekly insecticide sprays. Treatment 4 was the most profitable at larger orchard sizes. Generally, profits were higher and costs were lower for larger orchard sizes in all treatments. In 2007, treatment cost was highest in Treatment 3, followed by Treatments 3, 2, and 1, respectively.
One of the “New IPM” treatments was the most profitable of the management options tested. This is encouraging evidence that this approach is not only more environmentally safe, but also more sustainable economically than current practices. Gaining an additional year of field data in 2009 will place the economic estimates on firmer ground, and make the information sufficiently credible to share with growers, extension specialists, and the scientific community.
Objective 4. Communicate project findings to North Central Region apple growers through on-farm demonstration trials, field days, meeting presentations, statewide and regional newsletter and trade-journal articles, a project website, press releases, and an on-line Extension bulletin.
Two types of on-farm demonstration trials were conducted in 2008 to help develop reliable guidelines for use of the Brown/Sutton/Hartman sooty blotch flyspeck (SBFS) warning system. This system, developed in North Carolina and modified in Kentucky, extends the period between 1st-cover and 2nd-cover fungicide sprays until a total of 175 hours of wetness has been measured in the orchard canopy. After 2nd cover, sprays are made at 2-wk intervals until harvest.
On-farm demonstration trial #1:
In three commercial apple orchards in Iowa, we compared the effectiveness of the Brown/Sutton/Hartman SBFS warning system to a conventional, calendar-based fungicide spray regime in suppressing SBFS and other summer diseases.
Materials and Methods
Trials were conducted in cooperation with:
• Apple Ridge Orchard, Iowa Falls, IA (Mark and Lynn Fevold)
• Berry Patch Farm, Nevada, IA (Dean, Judy, and Mike Henry)
• Center Grove Orchard, Cambridge, IA (Steve Black)
Two cooperators set aside blocks of five trees (cv. Golden Delicious) and one cooperator set aside one cv. Gala, one cv. Chieftain, and three cv. Golden Delicious trees.
Spectrum WatchDogTM electronic leaf wetness sensors were placed in the lower canopy of an apple tree in each orchard and monitored weekly. Growers were kept informed of the accumulated hours of leaf wetness and advised to spray with Topsin M + Captan when the 175 hour threshold was reached. Following the second cover spray orchards were sprayed every 14 days until harvest.
At harvest, 50 apples from each tree (25 from the top half of the tree, 25 from the lower half) were evaluated for presence of codling moth, scab, bitter rot and the severity of SBFS. Percent of apples with SBFS were analyzed using PROC GLM with orchard as block. Percent of apples with bitter rot and scab were also compared.
No significant differences in SBFS incidence were observed between treatments (P=0.2434). The number of sprays using the SBFS warning system was reduced compared to the calendar-based treatment.
The Brown/Sutton/Hartman sooty blotch flyspeck (SBFS) warning system saved the cooperators an average of three fungicide sprays and was effective in controlling summer diseases. This result adds to earlier evidence that this warning system can perform well in Iowa orchards.
On-farm demonstration trial #2:
In our replicated field experiments in 2001-2003, the warning system was consistently as effective as calendar-based spray timing in suppressing SBFS and other summer diseases (secondary scab and fruit rots). But in demonstration trials in commercial orchards in IA, IL, and WI during that period, the warning system resulted in commercially unacceptable levels of SBFS in 12 of 28 site-years. One possible reason for these failures may be that a higher spray volume is necessary when timing the 1st-cover and 2nd-cover sprays using the SBFS warning system. In other words, it is possible that concentrate spraying (60 gal/A or less on semi-dwarf trees) may not be compatible with use of the warning system.
The objective of this on-farm trial was to determine whether spray volume (gallons per acre) of the 1st-cover and 2nd-cover fungicide sprays influences control of sooty blotch and flyspeck (SBFS) when using the SBFS warning system to time the 2nd-cover spray.
Materials and Methods
Three cooperators tested the impact of two different spray volumes on performance of the Brown/Sutton/Hartman SBFS warning system. Each of the cooperators set aside three blocks of five trees (cv. Golden Delicious) for each treatment. Two treatments were based on delaying the second cover using the SBFS warning system and included a "low volume” treatment and a “high volume”. The third control treatment used calendar-based timing of fungicides (2nd-cover spray follows 7 to 14 days after the first cover spray. Trials were conducted at:
• Deal's Orchard, Jefferson, IA (Jerald and Cindy deal)
• Community Orchard, Fort Dodge, IA (Greg and Bev Baedke)
• Pella Nursery and Orchard, Pella, IA (Jay Vermeer)
Following the second-cover fungicide spray, all treatments were sprayed with the grower’s standard volume every 14 days until harvest.
Spectrum WatchDogTM electronic leaf wetness sensors were placed in the lower canopy of an apple tree in each orchard and monitored weekly. Growers were kept informed of the accumulated hours of leaf wetness and advised to spray with Topsin M + Captan when the 175-hour threshold was reached for the low and high volume treatments. Following the second cover spray orchards were sprayed every 14 days until harvest.
At harvest 50 apples from each tree (25 from top half, 25 from lower half) were evaluated for presence of codling moth, scab, bitter rot and the incidence (% infested apples) of SBFS.
Incidence of SBFS varied greatly among orchards, ranging from 0 to 21%. However, no differences were observed among treatments (P=0.3691).
Fungicide spray volume for the first- and second-cover sprays did not influence the control of SBFS using the Brown-Sutton-Hartman warning system. The disease warning system was as effective in controlling SBFS as the calendar-based regime.
During the Iowa Fruit and Vegetable Growers Association annual field day on June 30, 2008, at the ISU Horticulture Research Farm, Gilbert, IA, the project’s M.S. student, Adam Sisson, presented the SARE project’s purposes and 2007 results to 60 attendees at a 20-minute stop in front of the SARE field experiment site.
With the addition of 2009 data, the project is likely to yield three research articles and three trade-journal articles on these topics:
1) the sustainability field experiment;
2) developing high-quality hard cider from Iowa apples; and
3) development of spray-volume and pruning guidelines for implementation of a sooty blotch/flyspeck warning system.
Only the third year of data is needed for each of these products to be ready for publication.
The field experiment is the first systems-level study of sustainable management in the Midwest that focuses on incorporation of scab-resistant apple cultivars. Since many scab IPM programs have collapsed due to proliferation of resistance to DMI fungicides, scab-resistant cultivars may be the most practical long-term option for Midwest apple growers.
Impacts and Contributions/Outcomes
Addition of 2009 data is needed before our outreach program can disseminate management recommendations reliably. With the 2009 data (assuming a typical year without a major freeze), we will have sufficient data to confidently share our findings with Iowa and Midwest apple growers, IPM specialists, and Extension educators via trade-journal articles and the project website.