As weather conditions are very damp across many cherry growing regions in Australia, and as the transition to El Nino in the months ahead has become official, it could be the right time to consider using dormancy breakers in your cherry orchard.
Insufficient chilling can result in a lack of, or a reduction in, fruit set in cherries.
Dormancy breakers are used world-wide.
Calculate your chill hours
To check how to calculate your chill hours, go to the CGA website and download the best document available for Australian conditions:
www.cherrygrowers.org.au/assets/170614_Chill_Chapter_Production_Manual_Final.pdf
Cultivar chill requirements
Also in this document is a calculation of chill required in a number of cultivars grown in Australia, so check that out as well.
Dormancy breakers
Dormancy breakers induce even flowering of a variety, and unless self-fertile, often late flowering cultivars do not have a pollinator with the overlap timing of blossom to lead to strong fruit set.
Earlier and more even flowering is likely to promote greater fruit set.
Large blocks of one or two varieties can be an issue at harvest time if all have to be harvested within a short window of a few days.
Use of dormancy breakers on half or part of a block could be considered in order to get a spread of harvest days for a variety, particularly if a lack of harvest labour is anticipated.
The aim is to get maximum production from the orchard, without compromising cherry fruit quality.
Below is a list of dormancy breakers sourced from the CGA document mentioned earlier, the Australian Cherry Production Guide 2017, Chill and heat requirements: from dormancy to flowering.
“It is strongly advised to use chemicals registered by Australian Pesticides and Veterinary Medicines Authority (APVMA) for use on cherries.
The only dormancy breaking chemical registered for use on cherries is Waiken®. Other plant bio-regulators registered are Gibberellic Acid (GA 3, GA 4 & GA 7) and Ethephon®. The fatty acid and their esters, Armobreak® (alkolated ammine) and Armogan® do not require registration nor does the fertiliser potassium nitrate (KNO3) or Erger® (natural compounds). Dormex® does not have registration.”
Quality cherries from the USA
Talking about fruit quality, cherries coming into Australia from the North-West USA are in our supermarkets and fruit shops; and quality is a high standard this season.
After 25 years, John Baker and son Mark have formally closed Produce Marketing Australia. We wish them both well.
John kindly provided a summary of the latest crop update, from Northwest Cherry Growers in the USA:
As of 5 July, 47,251 cartons had been shipped to Australia, compared with just over 38,000 cartons for the whole of 2022.
Judging from the report below there is still plenty of quality fruit to come, especially as the season is running significantly later than ‘normal’.
Here is part of the report that John refers to:
“The Northwest Cherry Growers have harvested the first 6,616,362 boxes of a crop that is expected to finish in the 21 to 22 million 20 lb. equivalent box range. The late start to the 2023 harvest has the Northwest Cherry industry coming into peak volume over the next few weeks…
As daily shipment has surged to almost 500,000 boxes per day the Northwest industry is bringing all domestic and export markets online.”
See this article in Tree Fruit July 2023
