Maximizing Cyclamen Mite Control: Strategies for Effective Chemical Applications

Wednesday, January 29, 2025

 As the anticipated registration of Magister for cyclamen mite control approaches, it's the perfect time to discuss how to optimize chemical applications for these challenging pests. To gain expert insights, we spoke with Slim Doghri from Gowan, representing Magister, and Eric Richter from Syngenta, representing Agri-Mek during the 2025 Nova Scotia Hort Congress which took place at the Old Orchard Inn outside Wolfville.

Challenges of Cyclamen Mite Control

Cyclamen mites (Phytonemus pallidus) present a significant challenge due to their ability to hide within plant structures and reproduce rapidly. Compounding the issue, growers are restricted to one application of Magister and two applications of Agri-Mek per season. This makes timing and strategy essential—not a matter of choosing one product over the other, but rather using both effectively for maximum control.

Preventing Cyclamen Mite Infestations

With limited chemical options, the best approach is prevention. Cyclamen mites have a narrow host range, meaning they do not move between hedgerows or survive on native plants. They are most commonly introduced through:

  • Infected planting stock
  • Spread from older fields to newer ones

In June-bearing matted row fields cyclamen mite populations will increase rapidly from over wintering adults.  Once eggs are laid they will hatch in 11 days, producing a population of mostly females.  The next generation will reach maturity in two weeks and start the cycle over again, each female producing about 90 eggs, laid in clusters. 


Cyclamen Mite with eggs at under a 20 x microscope
Photo credit: Virginia Co-operative Extension

Regular scouting is critical to detect problems early. Most growers lack the patience and microscope skills to intensively scout for cyclamen mite.  Intensive scouting requires collecting plant parts including developing buds, and young unfolded leaves and intense examination under the microscope. This is better left to a dedicated employee or a professional crop scout as it requires an abundance of patience and time.    Most growers are left scouting for symptoms appear, such as:

  • Compacted plant centers with stunted, crinkled leaves
  • Wilting and die-off of flowers
  • Severe yield and fruit quality reduction

Stunted plants with krinkled leaves often indicate the presence of Cyclamne mite
Photo credit: Viginia Co-operative Extension 


Once symptoms appear, populations have already surpassed treatment thresholds, making immediate action necessary before canopy closure of the rapidly developing strawberry plant restricts spray penetration down to the new leaves and crown area.

Magister: A New Tool in Cyclamen Mite Control

How Magister Works

  • Magister targets nymphs and adults, and controls eggs to a lesser extent.
  • Fast knockdown within 24 hours and residual control on treated leaves.
  • Effective against a broad spectrum of mite species.

Application Guidelines

  • Anticipated cyclamen mite label approval in July 2025.
  • Insecticide group 21A
  • Apply no more than one application per season, with a 1 day PHI.
  • Use a non-ionic surfactant at 0.25% v/v for better coverage.
  • Maintain agitation in suspension concentrate formulations.
  • Magister is a non-systemic contact product with a long residual.   Thorough coverage is key.
  • Use high water volumes (1000 L/ha or 105 gallons/ac).
  • Magister also controls powdery mildew.

Bee Safety Considerations

  • Toxic to bees if exposed to fresh residues (<3 hours old).
  • Do not apply to blooming or pollen-shedding plants unless exceptions apply (see label).

Agri-Mek: A Key Component in the Rotation

How Agri-Mek Works

  • Translaminar movement (absorbed into leaf tissue, but not systemic).
  • No effect on eggs; mites must ingest the chemical to be affected.
  • Causes muscle paralysis, stopping feeding within hours.
  • Mites take 2-4 days to die.

Application Guidelines

  • Limit of two applications per season, with a 3-day PHI.
  • Insecticide group 6, Which is different from Magister and great for rotation and resistance management.
  • Use 0.1%-0.5% v/v non-ionic surfactant.
  • Apply in 1000 l/ha.  Effectiveness drops off rapidly below 500 l/ha as shown by Justin Renkema, AAFC Vineland.  
  • Rainfast in 2 hours, but effectiveness will be better given a longer rain free period of up to 24 hours.
  • Avoid applying to hardened leaves, as absorption is reduced.
  • Do not tank-mix with oil-based products in strawberries.
  • If treating after renovation, apply 5 days after mowing to allow penetration before canopy regrowth
  • Growers should think about how they are going to achieve the high-water volume required.   Increasing spray pressure may produce excessively small water droplet leaving the spray prone to drift and fogging the exterior of the canopy.  Medium sized droplets maybe better at canopy penetration and coating the crown.   This may require two consecutive passes of the sprayer at opposing directions at 500 l/ha and a ½ rate of chemical in the tank.
  • Growers may need to think about spray water access in the fields to cut down on fill time and maintain efficiency in application.
  • After the decision has been made for an application for cyclamen mite the race maybe on to make the application before canopy closure, bloom and bee presence and harvest.   

Understanding the Impact of Group 3 Insecticides

Group 3 insecticides (pyrethroids, such as Matador, Silencer, Zivata, Decis, Up-Cyde, and Poleci) can have unintended consequences:

  • They may kill beneficial predatory mites (e.g., Neoseiulus cucumeris, Amblyseius swirskii), allowing cyclamen mites to increase in population unchecked.
  • Potential for hormoligosis—some mites, including two spotted spider mites, have been shown to increase egg reproduction when exposed to sublethal pyrethroid doses.

Final Takeaways for Growers

To achieve the best control of cyclamen mites, growers must:

  1. Prevent infestation by ensuring clean planting stock and minimizing field-to-field transfer.
  2. Scout early and frequently to detect mites before symptoms appear.
  3. Use Agri-Mek strategically, focusing on early applications when leaves are still soft and just after renovation. 
  4. Apply Magister closer to harvest but avoiding bee exposure, ensuring canopy penetration before closure. This will also provide powdery mildew control as temperatures and powdery mildew increase early summer.
  5. Ensure thorough coverage by applying before full canopy closure, and high-water volumes of 1000 l/ha.

Acknowledgments

A huge thank you to Eric Richter from Syngenta for his insights on Agri-Mek and Slim Doghri from Gowan for providing expertise on Magister during the Hort Congress presentation. Their knowledge is invaluable in helping growers maximize the effectiveness of their cyclamen mite control programs.