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Friday, May 3, 2024

May Newsletter

 Upcoming Events

Below is a summary of some of the industry events that are coming up in the next few weeks! The events listed below are primarily hosted by Perennia, and more information on each of them can be found here.
  • TunnelTalk
    • May 1 - Biological Spray Programs w Sonny Murray
    • June 13 - Greenhouse Ventilation w Matthew Kleinhenz
    • July 10 - Implementing Commercially Available Bio-Control Agents
    • August 14 - Expert Panel Discusses Greenhouse Structures
  • David Vantage Pro 2 Weather Station Maintenance Workshop - Cape John
    • Join us and learn how to properly care for your Davis Vantage Pro 2 weather station! During this in-person workshop, we’ll discuss the Davis recommended annual maintenance steps, and some common trouble shooting. We will also cover how to access your station’s data. 
    • Future sessions in Murray Siding, and Kentville
  • In-Person Pesticide Applicator Courses (Advertised by the NSDA)
    • May 14 @ Berwick Legion Hall
    • May 16 @ Truro
    • May 21 @ New Germany 
    • Reach out to your local NSDA Ag Rep for more information!

NSDA Program Updates

Get Growing Program - newly opened!

The Get Growing Program supports small farms in adopting specialized infrastructure and equipment. The program helps with the expansion of local agricultural production for local markets.

Program opening: 18 April 2024
Application deadline: 30 September 2024
Claim deadline: 31 December 2024

Examples of previously-funded projects from Appendix A include:


Weather Updates

Lets take a look at the weather data collected for this year, and how it compares to our historical records! Growing degree days (GDD) are important for anticipating key dates for crop growth stages, as well as pest emergence and flights. Consider some of the most persistent critters on your farm, and when they typically start to show up. Even if we are still early in the season, its a good reminder to revisit those dates, and think about what needs to happen to prepare for them to limit the impact they have on your farm. 


Figure 1. Degree day accumulation as of April 29, 2024. All data are taken from the Environment and Climate Change Canada weather station located at the Kentville Research and Development Centre, provided by Jeff Franklin. 

Table 1. Degree day accumulations as of April 29, 2024. All data are taken from the Environment and Climate Change Canada weather station located at the Kentville Research and Development Centre. Calculations are based on a start date of March 1, and calculated using the single-sine method. Provided by Jeff Franklin.


Remember the pest update for leek moth for the April newsletter? Reports from Keene Valley in New York show that their first leek moth of the season was found April 25. This area has a similar latitude to that of Nova Scotia, so keep your eyes peeled! 

Seasonal Considerations: Frost Tolerance and Protection

Provided by Matthew Peill, Acting Vegetable Specialist

With overnight temperatures dropping low in the last week or so, we wanted to send out a reminder on the frost tolerance of early season vegetable crops. These temperatures should serve as a guideline to assist with decisions as to when frost protection needs to be implemented in order to protect this year's plants.

With wide ranges of temperatures experienced from farm to farm within short distances of one another, it's important to check your closest weather station for the most accurate information.   

Asparagus  

Overall asparagus is very cold hardy, but emerged spears can be damaged to by frost. Spears can withstand temperature down to -2°C for short periods, but temperatures below this can cause damage.  

Brassicas 

Brassicas in general are cold hardy but there are differences between types. Cabbage and kale and are fairly hardy and can withstand temperatures of -10°C for short periods of time. Broccoli and cauliflower are less hardy and can be damaged when temperatures drop below -5°C.  

Alliums: 

Garlic is very cold hardy, even garlic with well-developed tops can withstand freezing temperatures for short periods down to -10°C without damage. Established onion are also quite frost tolerant with most varieties able to handle -4°C. However, onion seedlings can sustain damage when temperature hit 0oC.  

Frost Protection: 

There are a limited number of frost protectants in vegetable crops. For most large scale planting of vegetables it infeasible to use frost protections, but for small scale production susceptible crops row covers can be used during significant cold periods to provide protection. For protected producers, make sure your side vents are down before a cold night approaches, and consider row cover in extreme situations where heating is not an option.

Production Tidbits: The Value of Environmental Sensors

The information gathered from temperature and humidity sensors in any protected growing space is invaluable. Outdoor conditions are typically amplified under cover, so we cannot strictly rely on what we are seeing from local outdoor stations to know, and make decisions on, how to manage the growing environment. Ideally our temperature sensor is going to have the ability to upload information to your phone or device of choice. This provides the freedom to check on the greenhouse, without physically having to be there and cause disruption to your order of entry protocols. These types of sensors usually have the ability to set upper, and lower, limits as well, triggering a notification to be sent once we are in a zone where conditions are above or below their ideal values. 

Identifing imbalances in the greenhouse, before the crop shows us there is something wrong, is one of the key reasons to install sensors in the greenhouse. Plants are highly sensitive to mismatched growing conditions (ex. high humidity and low temperatures), and we can see poor quality, low yielding plants as a result. Take a look at figure 2 below. The highest temperatures of the day are paired with the lowest humidities, and vice versa, which is not the ideal scenario. We are also seeing huge swings in both of these values throughout the course of the day, putting unnecessary stress on the crop to constantly adapt to new conditions. Ideally the gray line would be more consistently in the range of the light green band running through the middle of the graph, which indicates a well-matched temperature and humidity. Situations like this should be addressed as soon as possible. If left unchecked, this can significantly reduce the yield of your crop, and quality of your produce. 


Figure 2. An image depicting temperature and humidity measured over a 48 hour time-span. The gray line represents the vapour pressure deficit, or VPD value.

For the situations where we aren't constantly checking our growing conditions, sensors with a capacity to store historical information make it easier for diagnosis oddities down the line. Say for example, you have a tomato crop that has a noticeable gap in fruit production in week 35. This historical information may point to a high temperature event which lead to poor pollination and/or fruit abortion, resulting in a consistent die-back of tomato flowers. On the other end of the spectrum, our string of cold nights in the previous week could have an impact on some newly emerging tissue, that may not be obvious until further down the line. 

Feature Pest/Disease
In Nova Scotia, striped cucumber beetles (yellow-green, about 6 mm long, with three black stripes down the back) are most common. They typically make their annual debut in the Annapolis Valley end of May, early June.  These pests are problematic in many ways:
  • Feeding damage can stunt plants
  • Predated flowers reduce fruit set and yield
  • Scarring on fruit by adult beetles reduce the marketability of the crop. 
  • Cucumber beetles vector bacterial wilt. 
Bacterial Wilt:

Bacterial Wilt is caused by the bacteria Erwinia tracheiphila, which overwinter in the gut of cucumber beetles. They are picked up by insect feeding on infected plants, then is transmitted to new plants through feeding wounds created by the beetles. The bacteria spreads quickly once introduced to the plant, and there is no way to control the disease once its been introduced. This pathogen can cause significant losses in cucumber and musk melon. It can infect squash and pumpkin, but typically to a lesser degree. 

What does it look like:
Initially presents as wilting tissue during the day that recovers at night. Leaf margins eventually turn yellow/brown, and the plant is unable to recover, leaving a permanently wilted leaf/plant. One way to distinguish between this and other wilt-causing agents is to do a bacterial stream test. Cut through stem tissue on your cucurbit, pushing the newly cut edges together and then slowly pulling them apart is a great way to start identifying the causal agent. 


Figure 3. A cucumber plant that was diagnosed with bacterial wilt. 

Figure 4. Bacterial 'streaming' observed in a canteloupe stem (Photo Credit: University of Minnesota Extension)

As always, your Perennia specialist and/or Plant Health Lab are happy to help you through the identification process if you have some unhappy plants cropping up. 
 
Early season control of cucumber beetle is essential for limiting the direct (feeding) and indirect (bacterial wilt) impacts on your crop. Regular scouting is crucial to properly identify the risk period on your farm. Cucumber beetle control should be implemented as soon as seedlings emerge. Newly emerging cucurbit plants are particularly susceptible to stunting and bacterial wilt, while older plants can withstand up to 25% defoliation. Early treatment is essential for beetle management.

Treatment options:
Applications of foliar insecticides may be required during peak beetle activity. Row covers and/or insect nettings are very effective means of excluding cucumber beetles in pesticide free or organic production. Covers should be placed overtop of plants as soon as they are growing outdoors, and uncover when plants begin to bloom. Delayed removal of the cover will impact pollination and fruit set. 

Some longer-term strategies for managing this insect include rotate your cucurbit crops, and rely on transplants instead of directed seeding to protect the plant during its most vulnerable stages. For additional options, check out this summary on managing cucumber beetles from eOrganic. 
 
Click here for Perennia's Pest Management Guides. If you haven't had a chance to play around with our newly formatted guides, our team hosted a webinar on how to navigate the tool and showcased some of its capabilities. You can find it in the "Recent Uploads' section below if you need a refresher. 

Recent Uploads

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That's all for now! If you have any questions, feel free to reach out to your extension specialist.

Happy growing everyone!
-Talia 
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