Strawberry growers around the world have experienced a hot summer, leading to increased pressure from cyclamen mites due to infected plants. This was what Kars Vreeswijk of Moleda saw when he toured several farms on various continents in August. Several strawberry plant nurseries and growers are now successfully combating the Cyclamen mite (Phytonemus pallidus) with the help of Plantsauna marketed by the Dutch-Norwegian company.
Biological control
With a slight infestation, growers sometimes still manage to control the cyclamen mite biologically. For this, growers deploy the predatory mite Neoseiulus cucumeris. "This method is only effective for control; you cannot eradicate the problem with it, especially in the various climate conditions that growers face today, because the predatory mite is sensitive to temperature," is what Kars was told by growers.
This summer was very hot. "With temperature fluctuations, the predatory mite stops being effective, and cyclamen mite is no longer controllable with biological control." The result is poorly growing plants and misshapen flowers, leading to no or poor fruit at all, with all the associated financial consequences for the grower.
Effect of cyclamen mite on the plant, Norway 2023
Hot and cold
By applying a special temperature treatment using aerated steam to slightly tease strawberry plants and cuttings, it is possible to produce disease-free plant material without chemicals. The Moleda Plantsauna offering this solution, has been in the market for about four years by now.
"Our focus was not on the strawberry grower, but on the plant nursery. The nursery performs Plantsauna treatment on mother plants and cuttings, ensuring that the grower's daughter strawberry plants are free of cyclamen mites and other diseases and fungi."
The Dutch-Norwegian company has also sold several Plantsaunas to production growers. "Often larger growers, but in some cases growers with a few hectares also choose to buy a Plantsauna. They have then suffered from cyclamen mites and other diseases and fungi for so many years that they like to treat their plants themselves too, so they can be sure they have a clean start at the beginning of their season."
Proudly, Kars shares a nice anecdote. "To a grower growing everbearers on a table-top system in tunnels in Canada, we sold two Plantsaunas this year. The grower, Vermeulen Farms Ltd in Nova Scotia, says thanks to good cyclamen mite control with the Plantsauna, he now has 50% to 100% more production. This does leave him short of pickers now, but for us, it is the proof that the Plantsauna offers incredible value to growers."
Strawberry plants at Vermeulen Farms Ltd in Canada, with treatment Plantsauna
44 degrees Celsius
Whereas a plant grower performs a Plantsauna treatment on the mother plants and cuttings before planting, a grower performs the treatment after receiving the plants, and before transplanting. To treat plants with Plantsauna, Kars advises growers on a specific regime.
"The grower receives the plants from their contracted plant nursery or their plant cultivation. The plants are placed in the Plantsauna before planting, where the temperature is raised to 37 degrees Celsius. Once the entire pallet of plants reaches 37 degrees Celsius, the Plantsauna remains at that temperature for one hour. After that, the rest cycle begins in which the plants rest and cool down for one hour. You then perform the third step of the treatment: 2 hours at 44 degrees Celsius, other diseases or fungi require 4 hours at 44 degrees Celsius. The total treatment time is between 6 and 8 hours. The Plantsauna performs this temperature regime fully automatically."
Rows of strawberry plants after treatment with Plantsauna
A quick calculation shows that a grower with 1 Plantsauna can thus give 3 pallets per day a sauna treatment. "We recommend the 4-hour treatment at 44 degrees Celsius," he says. Its effect has been confirmed in scientific literature. Norwegian-American research between 2015 and 2019 revealed the above protocol.
Yet at Moleda, they see growers in the Netherlands and Canada opting for the 2-hour treatment at 44 degrees, rather than the 4-hour treatment. "Indeed, the 2-hour treatment is already sufficient to eradicate 100% of the cyclamen mite in all stages, egg, larva, and adult."
Other diseases and fungi
Plantsaunas sold by Moleda are in Canada, Mexico, California (USA), New Zealand, South Africa, and throughout Europe. Moleda has mainly sold Plantsaunas to plant nurseries. "Plant nurseries outside the Netherlands often choose the 4-hour treatment at 44 degrees Celsius against cyclamen mites and other diseases and fungi such as Colletotrichum and Neopestalotiopsis, because of soil-bound cultivation."
A row of Plantsaunas at a customer in California.
The following fungi, pests, and bacteria can be treated with the Plantsauna:
· Cyclamen mite (Tarsonemus Pallidus)
· Stem base rot (Phytophthora Cactorum)
· Anthracose/black fruit rot (Colletotrichum acutatum)
· Powdery mildew (Podosphaera aphanis)
· Angular leaf spot (Xanthomonas fragariae)
· Grey mold (Botrytis Cinerea)
Plants without Plantsauna treatment on the left and right with treatment Plantsauna, Norway 2023
For more information:
Kars Vreeswijk
Moleda
+31 6 29297390
[email protected]
[email protected]
www.moleda.nl