Orchard Outlook Newsletter Vol. 23, No 18

Wednesday, November 8, 2023

Today's newsletter is the final Orchard Outlook issue for Volume 23 in the year 2023. In the last issue of the season I review a summary of tree health, crop load, pest pressures and fruit quality that can be easy to refer to in the future. There are also suggestions on winterizing orchards and a list of programs, workshops, and conferences. Cheers to you all for wrapping up another harvest season! 


Table of Contents:


  • 2023 Degree day accumulations
  • Precipitation
  • Tree health
  • Crop load
  • Notable pest pressure
  • Harvest fruit quality
  • Conclusion
  • Fall herbicide application
  • Fall soil pH adjustments
  • Orchard rodent control
  • Weather station maintenance
  • Reducing the risk of apple scab
  • Peach leaf curl
  • Plant your roots program now open for applications
  • New in-person pesticide courses fall 2023
  • Season extension enhancement program
  • List of workshops and conferences for the winter season


2023 Season Summary


2023 Degree Day Accumulations

Degree day accumulations and development were near-average by the end of the growing season. The totals are behind the warm years of 2021 and 2022. Harvest finished earlier than average for many. Throughout the season, the monthly average temperatures were either above or below the 25-year average with July, September, and October notably above-average by 1°C to 2 °C.


Figure 1: Heating degree day accumulations for plant (above 5°C) and insect (above 10°C) development from March 1 to Oct 31 for the past 17 seasons. Provided by Jeff Franklin (AAFC).
  • Approximately 1% more plant development heat units compared to the 5-year average, and 2% more compared to the 10-year average.
  • Approximately 3% less plant development heat units compared to 2022, and 3% less compared with 2021.
  • Approximately 2% more insect development heat units compared to the 5-year average, and 2% more compared to the 10-year average.


Precipitation

The precipitation total for the current growing season (red line) is well above the 10-year average (black line). There was a deficit of rain this past spring and most of the rainfall occurred during the summer and preharvest period. Jeff Franklin says that the records show that for the period April 1 to October 31, we had 915 mm of rain which is more than any other year in the 110 years of weather records in Kentville! The next closest year was 1977 with 901.5 mm. In 2019 we had 856.7 mm for this period.
Figure 2: Precipitation recorded in Kentville for the 2023 season (red line) compared with the 10-year average (black line). Provided by Jeff Franklin (AAFC).


Tree Health

Winter injury happened for the second consecutive year. Above-average temperatures in December and January delayed acquirement of cold hardiness. Extreme winter temperatures in February 2023 resulted in several types of injury. 

All regions exceeded critical winter temperatures that killed peach, nectarine, plum and cherry buds. Vegetative buds on peach trees were damaged so next year's crop is unclear but the structural wood appears generally healthy.

Sublethal injury to susceptible fruit trees may be contributing to further weakening, tree collapse, and cankers. In isolated cases, we have also observed xylem injury and split bark on apple trees that are entry points for pathogens. Some trees will decline and be less productive. Fall-pruned trees were at the greatest risk of injury. Injured trees attract borers that aggravate the problem. Southwest injury to the trunk also occurred and can be confused for cankers.

Figure 3: Possible symptoms of winter injury in apple trees including A) cankers, B) tree collapse, and C) xylem injury.

Periods of drought were concerning for newly planted and young trees. However, drip irrigation followed by timely rains seemed to prevent consequences. 

Crop Load

Apple trees started bloom by around May 14. Where bloom was good, the pollination and fertilization were also good. The outcome of chemical thinning depended on the program but generally the weather conditions were difficult or average to produce a thinning response. Last year the industry experienced a heavy crop load and it was expected that this year would produce a relatively smaller crop. On average, more crop was set on Honeycrisp than expected.

Notable Pest Pressure


Review of Apple Scab
The scab infection periods for the 2023 season are summarized in Table 1. Wetting periods produced infection events that occurred roughly once or twice every week. This season a total of 10 primary infection events were recorded, which is slightly less than has been typical in recent years. The event on June 2-6 was notable because it released up to 23% of total spore load. Other infection events in May also had heavy spore load.

Episodes of frequent and heavy rainfall were challenging for re-application of fungicide protection and for maintaining late season protection. This season was also the first time spray programs have had to adjust to the amended label for manzate (mancozeb) that restricts the number of applications to 4 per year.

Table 1: Summary of apple scab primary infection events recorded in Kentville in 2023, based on the Modified Mills Table and assuming a green tip date of April 15.



Review of Fire Blight
Last year’s widespread blossom infections contributed cankers and inoculum. Fire blight pressure at the start of the season was high due to carryover and new infection events. The following risks occurred:
  • The first blossoms in the Valley opened around May 9 with early regions in full bloom beginning around May 25. In general, blossom infections were possible on May 28 and June 1 during full bloom. 
  • Bacterial populations built rapidly in a single day on June 1 during warm temperatures. Even new blossoms that opened on June 1 and that were colonized by bacteria were susceptible to infection. Only blossoms open at the time of an antibiotic spray are protected from infection.
  • Trees with lingering blossoms were also susceptible on June 14 and it is possible that this risk of late blossoms was underestimated by many.
  • The risk of trauma blight occurred from four isolated hail events on May 8, May 14, May 17, and June 15.
Similar to last year, infections are allowed to take hold when 1) protection is not applied (if less susceptible varieties are ignored), 2) near festering infections from a previous season, 3) protection is applied on only every second row, and 4) poor coverage during full bloom. Fire blight showed up frequently this year where protection was inadequate. 

Harvest Fruit Quality

Early in the harvest window, temperatures were not conducive to red colour development and colour development seemed to play catch-up for the rest of the season.

Rainfall in summer and the preharvest period was heavy and relentless. The rain presented challenges for maintaining fungicide coverage. Leaf diseases such as Marssonina, Glomerella, and frogeye leaf spot were visible at harvest time suggesting that fruit were likely at risk of rots as well. There was an increased risk of minor diseases such as flyspeck.

On Sept 16, post-tropical storm Lee resulted in crop loss that varied depending on the orchard location and variety (less severe than Fiona 2022). Ambrosia was the worst affected. High winds and saturated soils also led to trellis failure in high crop load situations and occasional tree collapse. Some fruit were rendered unmarketable by cuts and bruises. Post-tropical storm Phillipe caused minimal damage.

Conclusion

Overall, the season had no shortage of challenges and everyone worked with what they were given. Winter injury happened for the second consecutive year, which in the case of the tender fruit (peach, nectarine, cherry and plum) has maintenance costs without the income expected from a crop. Fire blight management continues to be a key priority and there is now extra disease pressure due to new infections. A major challenge in summer was re-applying fungicide protection after heavy and long-lasting rain. Finally, warm temperatures in early September delayed red colour development.


Winterizing Orchards


Fall Herbicide Application

Fall is prime germination time for winter annuals, and perennials are susceptible to treatment because they’re actively storing reserves in their roots. Summer and winter annual species have populations that germinate in both fall and spring and therefore troublesome weeds may need to be managed at both times.
Refer to a previous article 'Fall Weed Control for Winter Annuals and Pesky Perennials' for more information. If applying herbicides is practical for you this fall, then consider the following suggestions.

Key points:

  • After harvest, consider using a post-emerge herbicide like 2,4-D to clean up weeds along with a residual product like Alion, Authority, or Chateau to save time early next season. Note the differences in the application directions for Chateau and Alion and refer to the labels for more detailed information. 
    • Chateau can be applied to young trees. 
    • Alion can be applied to only mature orchards with trees established for 3 growing seasons. Do not use Alion if you are planning single tree replacements next year.
  • Orchards without fall application of residual herbicides are expected to exceed weed thresholds in early spring before those treated with residuals.
  • If you are taking out orchard within the next 2-3 years for replanting, avoid applying residual herbicides. 
  • For glyphosate, wait until late spring to avoid translocation to fruit tree root systems.
  • Even if you are not set up to perform weed control in the fall, now is a good opportunity to identify what weed species are present to inform herbicide choices for early next year.

Fall Soil pH Adjustments

Soils in the valley are naturally acidic, and nitrogen fertilizers will slowly acidify soils over time. As soils acidify, nutrients such as calcium, potassium and phosphorus are less available for uptake by fruit trees. Other nutrients such as manganese and aluminum become more available and uptake by fruit trees can become excessive.

The pH of orchard soil should be between 5.5 and 6.6 (target 6.0) because nutrient availability is best within this range. Fall is the ideal time to make soil pH adjustments because it gives time for limestone to neutralize the acidity before the next growing season. Also in the fall, the dust from limestone applications will not interfere with growth or bloom.

Recommendations:

  • The results of a soil test will give a lime requirement based on your soil type and pH.
  • Apply calcitic limestome unless magnesium is needed from dolomitic limestone.
  • A surface application of no more than 3 tonnes/ha of limestone in any one year is recommended because higher volumes could be washed away and are ineffective.
  • If the lime is being worked into soil then you can follow the recommended rate on your soil report. Incorporating lime into soil will show benefits sooner than a surface application. A surface application moves down at a rate of about 1 inch per year.
  • If you have ongoing issues with lack of calcium in established plantings, consider banding gypsum at a rate of 4 tons per acre under trees. Annual applications have been shown to reduce bitter pit and senescent breakdown. Gypsum can also improve soil structure and improve water infiltration. Be aware that gypsum can reduce magnesium uptake. Gypsum will not replace the need for lime for pH adjustment.

Orchard Rodent Control

Rodents feed on tree bark in the fall and winter when other food supplies are scarce. The most common issue is when rodent feeding girdles the trunk of young trees at or near the ground surface or at the height of snow accumulation.

Recommendations:

  • Mow ground cover and maintain a weed-free strip to expose mice to predators.
  • Clean up drop apples from the tree row and alleyways to remove attractive food sources.
  • Be aware that using straw mulch can harbour mice.
  • If rodent activity is observed (mouse tunnels, droppings and chewed apples), consider the use of rodenticide. Bait stations manage the risk of poisoning other species and the control is long-lasting.
  • Bait stations placed on the perimeter of the orchard target mice moving into the orchard from bordering fields, fence lines or ditches. Pay particular attention to orchard blocks that neighbour corn and soybean fields.
  • Install tree guards, if feasible, on young trees. Remove after snow melt in spring to avoid fungal problems at the base of the trunks.

Weather Station Maintenance

Perennia is contracted by NSFGA for spring and fall maintenance of the ten NSFGA-owned Davis weather stations. Weather station equipment must be maintained to ensure that the data is accurate. Since you are using the weather data for your decision making, NSFGA and Perennia would like to keep you informed about the maintenance for your own peace of mind.

The fall maintenance is now complete for all ten stations and was done on dates within the period of Oct 5 to Nov 3. The fall maintenance includes checking for firmware updates, levelling, cleaning, and inspecting components for damage.

Also please note that temperature/humidity sensors were replaced on all stations in spring 2023 as part of a regular 2-year preventative maintenance schedule.

If you own your own Davis weather station, consider doing fall maintenance. Davis offers a 3-minute video and description on how to do your own maintenance. 


Disease Management


Reducing the Risk of Apple Scab

Scab spores can be reduced for the next growing season by accelerating the decay of infected leaves in the fall of the current season. The benefit is less disease pressure next spring that can help to reduce the risk of primary scab infections. All efforts to reduce primary inoculum for next year will be helpful for scab control under new fungicide restrictions.

Recommendations:

  • Spraying urea (46-0-0) onto leaves on the ground can reduce spores by about 66%. The recommended rate is 50 kg/ha in 1000 L/ha of water. The solution could alternatively be applied to full trees as leaf fall begins. Urea should be dissolved in warm water before putting it in the tank. The 50 kg/ha rate will supply approximately 23 kg/ha of nitrogen to the ground, so nitrogen application next spring should be adjusted accordingly.
  • Flail chopping all plant matter on the orchard floor in November can reduce the number of scab spores by as much as 85%. Flail chopping in only the alleyway can reduce scab spores by as much as 50%. Why does chopping work? Dr. Gordon Braun explained in a year 2000 publication that:
    • "By chopping up leaves finely, they are more easily broken down by bacteria and molds to be consumed by earthworms."
    • "The apple scab fungus needs to mate with the opposite mating type and smaller leaf pieces reduces the likelihood of the two meeting."
    • "The smaller fragments also fall deeper into the grass and have a greater probability of resting in a position which is less than horizontal which reduces the ability of the ascosopres being successfully discharged into the air currents and carried to susceptible leaves."
  • Using both shredding and urea applications can produce the best results and will help reduce the risk of other leaf diseases as well.

Peach Leaf Curl

Peach leaf curl is a fungal disease of peaches and nectarines that is usually well-controlled by a fungicide application in spring or late fall. Infections occur in the spring at bud swell when overwintering spores are washed from the surfaces of the bark. Therefore, a fungicide application prior to bud swell in the spring is preferred. However, occasionally early warm temperatures combined with extended snow cover can make spring applications challenging.

Recommendations:

  • The spores overwinter on the bark, so fall applications for peach leaf curl should be tailored to provide complete coverage of trunks and branches. Fall application should be made after 75-100% of leaf drop has occurred and when the temperature is above freezing.
  • Unusually wet winter weather with heavy rain can wash off a protectant fungicide applied in fall. If residues are washed off, re-treatment in spring before buds swell is recommended. 
  • Chlorothalonil (Bravo) has been the most effective fungicide in Nova Scotia. Only 1 spray of Bravo may be applied per year, meaning it cannot be applied in both spring and fall. Other products registered for suppression or control include fixed copper products and Equal/Syllit.


Events and Notices


Plant Your Roots Program Now Open for Applications

The costs of starting a farm have gone up significantly in recent years and the Department of Agriculture is responding by expanding the ways it can help emerging producers.

The Plant Your Roots program is a collaboration between the Department and the Nova Scotia Farm Loan Board to help support the next generation of farmers. This will replace the the FarmNext program with a substantial increase in available support.

If you have recently borrowed money to start or secure an ownership stake in a farm business, you may be eligible for a rebate of up to four years’ worth of interest, valued at up to $100,000. To apply you must have an approved loan within the last six months (loans dating back to April 1, 2023, will be accepted this year) and have acquired at least 25% ownership in the business. Applicants can borrow money for the following eligible activities:
  • Innovative technologies with a focus on labour efficiencies
  • Technologies supporting local food production
  • Commercial farm purchases
  • Investment in properties to create active farm locations or reactivate viable farmland.
What does this mean in practical terms? You could secure a loan to purchase an ownership share in a farm or own a commercial farm outright. You could buy a property with farming potential and start a new farm business from scratch. You could develop a farm business on a property you already own but have not previously used for farm purposes, borrowing funds for the equipment required to produce food.

What does this mean to your bottom line? A loan of $500,000 at 6.95% interest amortized over 20 years would incur approximately $99,000 in interest in the first four years. By applying to Plant Your Roots, a rebate for this interest would be paid to the applicant and can be used to reduce the loan principal or offset other start up expenses.

Contact your local Agricultural Representative or the Nova Scotia Farm Loan Board to learn more. Any formal loan with a fixed interest rate can be eligible for Plant Your Roots but the Farm Loan Board are agricultural lending experts and a great place to start!


Marbicon New In-person Pesticide Courses – Fall 2023

Pre-Exam courses are $125. Five recertification points are available (T2380 $110)
A manual is provided for pre-exam courses.
Mon Nov 13 – Berwick ( Legion Hall, 232 Main St.)
Weds Nov 15 – New Germany (Anglican Church Hall, Hwy 10)
Fri Nov 24 – Bible Hill (Truro Horsemen’s Club, 288 Main St.)

Recertification workshops (NOT preparation for the exam) for 5 points (T2381 $110)
Fri Dec 1 – Bible Hill (Truro Horsemen’s Club, 288 Main St.)
Mon Dec 4 – Berwick (Legion Hall, 232 Main St.)
Weds Dec 6 – New Germany (Anglican Church Hall, Hwy 10)

Additional courses and workshops will be offered in the new year, at many more locations.
For all courses, doors open at 8:30 for a 9:00 AM start.
Most courses will finish around 3:30-4:00, pending needs.
No food or beverages are provided; bring your own.
There will be a break for lunch.

The provincial exam is NOT offered during any of these courses, and a course is NOT required before writing the exam. But most people find a structured course very helpful. All certification categories are covered in these courses.

For course registration and further information, contact Jim Jotcham at marbicon@eastlink.ca or at 902-538-7101. Payment is due on the day of the course: cash, cheque, e-Transfer or PO number. HST is included.


Season Extension Enhancement Program

Intake began October 1, and applications are assessed on a first-come, first-served basis with limited funds available. Presented by Horticulture Nova Scotia, the Season Extension Enhancement Program is designed to help support fruit and vegetable growers investing in innovative technologies to extend their growing season, adapt to a changing climate and open up new market opportunities.

The program encourages and supports Nova Scotia’s fruit and vegetable producers by providing financial assistance with the following on-farm infrastructure: adopting season extension technologies; enhancing storage capacity; adopting and developing irrigation capacity for field operations.

Eligible applicants are producers of fruit and vegetables grown and sold in Nova Scotia.
Farming activities must be carried out within the province of Nova Scotia.
Registered Farmers in Nova Scotia with annual fruit and vegetable income shown in Statements of Farming Activities in most recent 2 years of submitted Tax Returns (2020, 2021, or 2022).

Note: Applicants can apply for 1 or multiple streams to reach maximum funding.
The application and guidelines are available at www.horticulturens.ca or via this link.
For more information, please contact our office at 902-678-9335 or email programs@horticulturens.ca

This project is a partnership of Horticulture Nova Scotia and the Nova Scotia Department of Agriculture.

Upcoming Events


Edited by Michelle Cortens, Tree Fruit Specialist
Perennia Food and Agriculture Corp.

By Michelle Cortens at November 08, 2023
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