The temporal distribution of cyclamen mite, Phytonemus pallidus (Acari: Tarsonemidae), in strawberry and comparison of sampling methods

Abstract

Cyclamen mite, Phytonemus pallidus (Banks) (Acari: Tarsonemidae), is a pest of strawberry, Fragaria × ananassa Duchesne (Rosaceae), that injures new growth, resulting in damage to leaves and fruit. The primary source of cyclamen mite in strawberry is infested planting material, and damaged plants tend to occur in small, isolated patches in perennial production systems. In the present study, we determined through repeated sampling of strawberry plants in Ontario and Saskatchewan, Canada whether relative cyclamen mite population levels were stable in commercial fields and whether overwintering and field renovation (mowing) affected populations. In Ontario, cyclamen mite counts were significantly correlated for 66% (10 of 15) of the paired comparisons from six sampling dates in more than one year, indicating a relatively stable distribution of cyclamen mite patches in strawberry fields. Winter caused high mortality (100 times fewer mites in spring than fall) and mowing caused some mortality (10 times fewer mites post- than pre-mow). We found that more cyclamen mite motiles were extracted from plant material stored in ethanol and triple-washed than were extracted using Berlese funnels, although counts from leaves were correlated between methods. No cyclamen mites were found in Saskatchewan. Knowing that cyclamen mite patches are local and spread is negligible will facilitate targeted applications of controls.

Control of Phytonemus pallidus (Acari: Tarsonemidae) from strawberry transplants using controlled atmosphere temperature treatment

“…Once the liquid in Petri dishes had settled for at least 1 min, mobile forms (adults and larvae) of P. pallidus were counted under a stereomicroscope (Olympus Life Science, Model SZ2-ILST) at 45×. As suggested in previous experiments (Renkema et al 2022), this triple-washing extraction method offers better mite recovery and convenience for sample processing than extractions with Berlese funnels.…”

Ultraviolet-C irradiation has no short-term, direct effects on cyclamen mite (Phytonemus pallidus (Banks)) in strawberry

“…Cyclamen mite (Phytonemus pallidus (Banks)) is a common pest of strawberry and ornamental plants in many regions of the world (Gerson and Weintraub 2007;Vacacela Ajila et al 2018;Renkema et al 2022). All life stages are found primarily in protected parts of the plant, such as tightly wrapped unopened leaves and flower buds, and are difficult to detect at low population levels in nursery and fruiting fields by visual observation (Fitzgerald et al 2008).…”

Biopesticide transplant dips and foliar acaricide applications for control of cyclamen mite (Phytonemus pallidus) in strawberry.

“…Crowns (1-2 per plant) were cut at the soil level and placed in a centrifuge tube with ethanol. Tubes were stored in a refrigerator until a triple-wash-and-rinse method(Renkema et al 2022) was used to count motiles (adults and larvae) using a stereomicroscope at 20X magni cation; eggs were not counted.Field biopesticide dips and foliar acaricidesOn 1 June, each biopesticide was prepared at the recommended rate (Table1) in 6, 2L plastic bottles with distilled water and Agral® 90 (0.25% v/v). Each bottle was shaken by-hand for ~ 1 min and then poured into a white, plastic pail (4L).…”

“…Overall, spiromesifen, like spirotetramat, also a Group 23 mode of action (IRAC 2024), has moderate effects on cyclamen mite(Łabanowska et al 2015) and could be used in rotation with other acaricides to maintain low population levels.Acaricidal effects on cyclamen mite translated to measurable improvements in yield in the following season, almost 1 year after application. Cyclamen mite numbers were low 6 weeks after application, likely remained low during autumn, and then were further reduced by winter conditions(Renkema et al 2022). Even though cyclamen mite numbers were close to or greater than nominal thresholds less than a week before harvesting started in spring 2023 (Government of Alberta 2008; Burrack and Teonnisson 2014), injury levels to fruit were still quite low (0.5 to less than 2%), and strawberry weight of about 9 g averaged over the harvest season is near normal for 'Jewel'(Hughes et al 2013).…”