How should strawberries be sprayed for ticks after harvesting? - briefly
Apply a post‑harvest acaricide spray that is registered for low‑residue use, covering the fruit uniformly and removing any excess solution promptly. Observe the label‑specified pre‑harvest interval before the berries are sold.
How should strawberries be sprayed for ticks after harvesting? - in detail
After strawberries are removed from the field, residual tick populations can persist in the plant canopy and surrounding soil. Effective post‑harvest treatment requires a systematic approach that addresses timing, product selection, application technique, and safety considerations.
The first step is to select an acaricide that is approved for use on berries and retains activity on dead plant material. Common options include spirodiclofen, abamectin, or a sulfur‑based formulation. Verify label instructions for pre‑harvest intervals (PHI) and maximum residue limits (MRL) to ensure compliance with food safety regulations.
Timing of the spray should coincide with the end of mechanical harvesting, when foliage is still intact but fruit removal is complete. Apply the product within 24 hours to prevent ticks from re‑infesting emerging shoots. If weather forecasts predict rain within the next 12 hours, postpone application to maintain coverage.
Application technique influences efficacy:
- Equipment: Use a low‑volume boom sprayer equipped with fine‑mist nozzles (100–150 µm droplet size) to achieve uniform coverage of leaves and stems.
- Calibration: Adjust flow rate to deliver 200–250 L ha⁻¹, depending on canopy density. Conduct a spray‑board test to confirm droplet distribution.
- Coverage: Aim for complete leaf wetting, including the undersides where ticks often reside. Avoid excessive runoff that can cause soil contamination.
- Environmental conditions: Apply when temperature is between 15 °C and 30 °C, relative humidity exceeds 60 %, and wind speed is below 5 km h⁻¹ to maximize adhesion and reduce drift.
Safety measures are mandatory:
- Operators must wear protective clothing, gloves, and eye protection.
- Follow the product’s re‑entry interval (REI) before entering the treated area without protection.
- Record the batch number, application rate, and date for traceability.
Post‑application monitoring should include:
- Visual inspection of foliage for tick presence 3–5 days after treatment.
- Trapping or beat‑sheet sampling to quantify residual populations.
- Documentation of any adverse effects on plant health or non‑target organisms.
If monitoring indicates insufficient control, a second application may be scheduled after a minimum interval of 7 days, respecting the cumulative maximum dosage stipulated on the label.
By adhering to these guidelines—selecting a registered acaricide, timing the spray immediately after harvest, employing calibrated low‑volume equipment, ensuring thorough leaf coverage, and observing safety and monitoring protocols—growers can effectively reduce tick infestations on harvested strawberries while maintaining compliance with food safety standards.