Cyclamen mite be a challenging pest for strawberry growers this year
Cycalmen mite damage is a common issue berry growers have seen this year, reducing vigour and affecting yields of June-bearing strawberries. Could cyclamen mites have injured your fields this year? It is important to recognize cyclamen mite damage as early as possible to begin to manage this challenging pest and stop the population from growing. Did your fields have reduced vigour this season? Are leaves toughened and crinkled? Was new growth short and small? Bronzed berries? Cyclamen mite could be the prime suspect. Check your fields for these symptoms and for the mites before mowing them during renovation, and if you find symptoms OR mites, begin to use the management steps listed below.
Identifying cyclamen mites:
Walk your fields and check new, unexpanded foliage looking for mites and eggs. These mites are very small and hard to see with the naked eye. They can be recognized by their egg masses, which look like piles of salt on the midrib of folded, young leaves, but often the damage will be noticed first.
High infestations can lead to distorted, crinkled, toughened leaves and can stunt plant growth. This was very evident in a few fields this spring, where plants lacked vigour, petioles were short, and leaves were small and compact around the crown. In severe situations you might find damage to the bloom and developing fruit with prominent seeds and bronzing. If mites feed on blossoms they will wither and die, and yields could be reduced.
Check your older fields AND your new fields for damage before renovation. Below are a few pictures from the field this year to help you identify cyclamen mite damage:
Populations can grow very quickly and spread around the farm after a population becomes established, making it very important to recognize damage as soon as possible. In hot temperatures they will move down to the crown into protected parts of the plant. They are often most active in the spring and fall, and go quiet at renovation, so they may be more difficult to find, but the damage will be visible. For more information on life cycle and biology visit the strawberry page on Ontario.ca/cropIPM .
Controlling cyclamen mite:
Reduce the risk of introducing cyclamen mites to new fields. This is very important to protect your establishing fields. Cyclamen mites can be carried to healthy, clean fields on equipment, clothing, animals and people. Work in new fields first before moving to older, infested fields, and avoid planting new fields next to old ones if possible.
For chemical control the most effective time to target cyclamen mites is when plants are succulent and actively growing, as buds emerge from the crown, either in the spring or after renovation- plan to apply a miticide soon. Products available for cyclamen mite control are Agri-mek SC and Vegol Crop Oil. After harvest Vegol crop Oil can be applied in a high water volume for cyclamen mite control. Agri-mek is also registered for two-spotted spider mite (TSSM) control post-harvest; if you are applying Agri-mek post-harvest for TSSM you may have efficacy on cyclamen mites.
Apply Agri-mek once there is new growth after mowing, approximately 5 days. Apply at 225 mL/ha in 750-1000 L water/ha, with a non-ionic surfactant at 0.1-0.5%. Do not use these surfactants close to Bravo, Echo, Captan, Maestro, Folpan or Sinbar. Do not apply sinbar after applying Agri-mek- wait 5-7 days after Agri-mek to apply sinbar. Apply Agri-mek under slow-drying conditions to improve uptake into the leaves. If you do not spray for cyclamen mite now flag problem areas for control in August/September or in the spring.
Beneficial mites and thrips can also be used to control cyclamen mite, however some insecticides for berries are hard on beneficials and use of these insecticides can lead to mite flare ups. Avoid using pyrethroids, and next spring limit your sprays for clipper weevil where possible, as cyclamen mite and clipper weevil are active at the same time.
For more information on what we are finding and management practices, follow this OnFruit (https://onfruit.ca/ ) blog to receive regular updates.
What should we do with old infested fields that will be getting disced under after harvest that are next to new fields? Should they get sprayed or or just border spray? How far can cyclamen mites travel on their own?
You don’t need to spray the old fields, but discing them earlier the better. Cyclamen mites don’t travel far on their own, but they will travel on equipment, people or animals, so when you are renovating your fields make sure to work in the new fields first before moving to the old fields you are removing.