Recommendations for Use of ReTain

ReTain is a plant growth regulator and an effective preharvest drop control. It inhibits the production of ethylene in maturing apples. ReTain may also increase soluble solids, colour, fruit size, fruit firmness and reduce water core. 

The following comments are extracted from Publication 360, Fruit Production Recommendations. The complete version can be found on the OMAFRA website.

• Apply Retain 4 weeks before anticipated harvest.
• Use a starch-iodine test to determine optimum harvest maturity. Expect up to 7 to 10 day delay in maturity from ReTain.

Recommended use 4-5 weeks before anticipated harvest

• Use one, 333 gram pouch (50g active ingredient) of ReTain/ 0.40 ha (1 ac). Use with Sylgard 309 (surfactant) at 0.5-1.0 L/ 1000 L of water.
• Apply four weeks before anticipated harvest. It is better to be early rather than late. Once ethylene production has begun, it is difficult to suppress. 

Precautions

• When you mix ReTain with the surfactant, keep agitation to a minimum because Slygard 309 has a tendancy to foam.
• To minimize foam, add Slygard 309 last, when the tank is full.
• Slygard 309 is the only surfactant registered with Retain in Canada. If the rate of ReTain is reduced, maintain the Slygard rate at 0.05%- 0.1% v/v.
• Discard any unused spray material at the end of each day.
• Do not tank-mix with other products except Dipel or Foray.
• Do not overhead irrigate for eight hours after applying.
• Adjust spray water volumes based on tree size and spacing. Do not apply to the point of runoff. Apply under slow drying conditions. 1000L water/ ha is usually adequate.
• For best results, maintain a spray water pH of between 6 and 8. 

Note: Segregate ReTain-treated fruit in storage to reduce exposure to ethylene.

•  Additional Considerations When Using ReTain
• Spray only trees that are healthy and not under severe drought, insect, disease, or nutritional stress.
• Gala strains, Golden Delicious types and Honeycrisp appear to be more responsive to ReTain compared to McIntosh - crop maturity and development may be impeded.
• For multiple pick cultivars such as Royal Gala, for best results time application four weeks from the second harvest pick date.
• The harvest window for treated cultivars is shorter but delayed, resulting in fewer pickings and increased harvest efficiency.

Related Links:

• OMAFRA Publication 360

| OMAFRA Newsletters |