Publication 360 - Guide to Fruit Production - Chapter 7: Tender Fruit
Growth Regulators for Sour Cherries

Pub 360, Guide to Fruit Production > Chapter 7: Tender Fruit > Growth Regulators for Sour Cherries

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Excerpt from Publication 360, Guide to Fruit Production , 2012-2013,
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Table of Contents

1. Growth Regulators for Sour Cherries
   • Ethephon (Ethrel)
   • Gibberellic acid
2. Sour Cherry Calendar
   • Dormant
   • Prebloom
   • Bloom
   • Petal fall
   • Shuck split
   • First cover (12 days after shuck split)
   • Special sprays (when monitoring indicates the need)
   • Second cover (12 days after first cover)
   • Third cover
   • Special sprays (when monitoring indicates the need)
   • Preharvest
   • Postharvest
   • Special sprays (when monitoring indicates the need)
   • Postharvest fruit treatment
   • Fall spray
3. Other Information on Sour Cherries
   Table 7-6. Products Used on Sour Cherries
   • Table 7-11. Activity of Fungicides on Stone Fruit Diseases
   • Table 7-12. Activity of Insecticides and Miticides on Tender Fruit Pests
   • Notes on Tender Fruit Insects & Diseases
   • Tender Fruit Nutrition
4. Sour Cherry Calendar (PDF 64 kb)
5. Chapter 7 - Tender Fruit Calendar (PDF 40 KB)
6. Related Links

 

Growth Regulators for Sour Cherries

Ethephon (Ethrel) to promote fruit loosening of sour cherries at harvest

Ethephon (Ethrel) can be used in sour cherry orchards to promote fruit loosening, uniform maturity and to facilitate mechanical harvest.

The effectiveness of Ethrel treatment depends on several factors, particularly ambient temperature and tree vigour. The response time of the tree to Ethrel application increases with higher temperatures and decreases at lower temperatures. For this reason, apply Ethrel only in the temperature range of 18-30ºC. Remember, hot weather shortens the time needed for response.

Tree Vigour: Tree vigour also affects the effectiveness of Ethrel treatment. Do not spray trees that have low vigour or are severely stressed by drought, disease or winter injury, which is indicated by gumming on the trunk and scaffold limbs. Only treat trees that are vigorous and in good health.

Rates: Apply ethephon at a rate of 2.75 L/ha (applied in approx. 2,400 L of water per ha). Fruit should be enlarging rapidly, with the grass-green colour beginning to turn yellow or develop a tinge of red. This generally coincides with 7-14 days before anticipated harvest. This rate helps to loosen fruit to facilitate mechanical harvesting. Consult the product manufacturer for further information.

Concentrate spraying: Application of ethephon in concentrate sprays (i.e. 1,000 L of water per ha or less) achieves the same level of loosening as dilute applications. Uniform coverage is important.

Tank-mixing: There is little or no data regarding tank-mixing ethephon. Do not tank mix with foliar nutrients or compounds such as fruit-cracking inhibitors, etc. While no problems have been reported by growers for tank-mixing ethephon with the fungicides and insecticides commonly used at this time, it is possible these materials may act as a buffer to the ethephon and thereby alter activity.

 

Gibberellic acid

To moderate early production, apply gibberellic acid (GA) at 15 ppm in the fourth year. This allows flowering in year five at a reasonable level rather than allowing heavy bloom and production. Overproduction can significantly reduce growth in future years.

For mature Montmorency sour cherry trees infected with cherry yellows virus, apply GA annually. This helps maintain and extend high fruiting capacity and reduces occurrence of blind nodes through the stimulation of lateral shoots and spurs.

Apply about three weeks after full bloom, from shuck fall to two weeks after shuck fall. Use concentrations of 10-20 ppm (15 ppm is most common). Use lower rates on more vigorous trees. For specific application instructions, which include temperature and humidity, consult the product label.

Related Links

• Integrated Pest Management (IPM)
• Pesticide Application and Safety
• Pesticide Companies and Agents
• Search the PMRA website
• Ontario Minor Use Program
• OMAFRA Publication 505: Ontario Weeds
• OMAFRA Publication 360: Fruit Production Recommendations