D.S. Cole Shares Its Experience Using Predatory Mites

Amblyseius californicus is suitable for situations with a low density of spider mites.
Amblyseius californicus is suitable for situations with a low density of spider mites.

Spider mites are one of the most difficult pests to control in greenhouse operations. They are an annual problem that many growers find difficult to control using cultural and chemical means. Biological agents may be the weapon that allows you to succeed at controlling mites. D.S. Cole Growers has been having great success integrating a predatory mite release schedule with chemical controls to finally get the upper hand in this endless battle.

Biological control of spider mites generally revolves around the release of predatory mites from the family Phytoseiidae, which preys upon insects and other mites. The main advantage of these little hunters is that many species can establish themselves in the crop. They are quite adept at finding mites and consuming them before they become a much larger problem.

Spider mites have several qualities that make them very difficult to control. They feed on the underside of leaves and the action of feeding often causes the leaves to curl downward, creating a protected mite metropolis that is difficult to treat with chemicals. The lifecycle of a spider mite is quite short, which creates many overlapping generations. With multiple life stages at any given time, a chemical that only targets one or two stages (most available chemicals) is unable to eliminate the problem. Another effect of the short lifecycle is the rapid acquisition of resistance.

We Experimented With Predatory Mites To Address A Problem

Frustrated with the increasing challenge of killing mites using chemicals, D.S. Cole Growers took a tip from a skilled grower in Florida and began aggressively releasing predatory mites on several mite-prone crops in July 2013. As an experiment, we released Amblyseius californicus mites onto some tropical plants that had an established spider mite population already. Over the course of about four weeks, the A. californicus mites overtook the spider mite numbers. They were able to find A. californicus mites establishing on the plants and the spider mite population plummeted. By August, the undersides of once-infested leaves were covered with the dry husks of dead spider mites.

After this experiment, we halted pesticide applications and integrated the release of A. californicus mites into the production of cordyline, dracaena, hedera and other mite-prone plants. The grower has not needed to apply a single miticide on these crops since July. Weekly scouting has not located a single mite on these crops.

Phytoseius persimilis is most effective when a mite population already exists. Photo courtesy of Syngenta
Phytoseius persimilis is most effective when a mite population already exists. Photo courtesy of Syngenta

Comparing Costs Of Biological Versus Chemical Controls

A frequent question is how much these beneficials cost in comparison to chemical controls. Here is a simple cost comparison between chemical and biological control in a one-acre greenhouse filled with a mite-prone plant. These numbers are for material costs only.

Using a weekly miticide rotation including Pylon, Tetrasan, Sanmite, Akari and Floramite in a one-acre greenhouse would end up costing an average of $150 per application, totaling about $7,800 per year. This is based on using 100 gallons through a hydraulic sprayer. You may use more or less. Some growers may need to use more than one application per week in the spring and summer months.

Using a biweekly (some growers do triweekly or monthly releases) release of 25,000 Amblyseius californicus mites per acre will cost $98 per release, totaling $1,274 annually. A higher release rate of 75,000 A. californicus per acre would cost $294 per release, totaling $3,822 annually. If applied using a blower, the labor used to release is similar to doing a chemical application using a hydraulic sprayer. Beware that buying small quantities of predatory mites is more expensive than these large releases.

How To Get Started With Commonly Used Predatory Mites

The two most commonly used predatory mites for controlling spider mites in greenhouse crops are Amblyseius californicus and Phytoseius persimilis. There are other species available but they tend to be pricier, and for the average greenhouse grower, they have no additional value over the standards.

Phytoseius persimilis is an agile, bright red mite with a voracious hunger for spider mites. Phytoseius persimilis is most effective in situations where a mite population already exists, as they will quickly starve without two-spotted spider mites as prey. This predator multiplies faster than the two-spotted spider mites, and will quickly overtake an infestation. It prefers temperatures between 59°F to 77°F (15°C to 25°C) and a humidity above 60 percent.

Retrofitting a leaf blower to distribute predatory mites in your greenhouse is effective and saves labor.
Retrofitting a leaf blower to distribute predatory mites in your greenhouse is effective and saves labor.

Amblyseius californicus is a hardy, slower-moving predatory mite. It is more suitable in situations where there is a low density of spider mites. These mites can subsist and reproduce on a variety of food sources, including other arthropods and even pollen. A. californicus is hardier than P. persimilis in temperatures above 77°F (25°C ), as well as in low-humidity environments (less than 60 percent). It is significantly more tolerant of pesticides than P. persimilis, allowing a variety of chemicals to be used without harming the population of predatory mites.

Both mites can be released at rates between 0.5 mites/square foot (preventative) and 3 mites/square foot (heavy pressure, existing mite population). D.S. Cole Growers releases bi-weekly, but others have decreased applications to tri-weekly or monthly.

Our Conclusion: Using Natural Predators Is A Great Option

Predatory mites have been shown to be a competitive alternative to miticide applications in most growing situations. By using these predatory mites as the backbone of your mite control strategy, you can reduce your dependence on chemical controls. In addition, the use of predatory mites offers a benefit for the end consumer because the plants come preloaded with a colony of predatory mites.

Topics: ,

Leave a Reply

One comment on “D.S. Cole Shares Its Experience Using Predatory Mites

  1. I grow mandavillias in palm bch county Fl. Out in full sun. Which predatory mite would use suggest using. What insecticide/mitecides can be used with out harming beneficial mites?

    Trey

More From Crop Inputs...
Heuch Pink Fizz_featured

March 2, 2015

Intergeneric Crosses Are A New Perennial Trend

Intergeneric crosses, oddities some botanists say are an impossibility, have made serious inroads in the perennial world.

Read More

March 2, 2015

Robots Grab Hold Of Growers’ Material Handling Needs

Harvest Automation’s HV-100 robots automate one of the hardest, most labor-intensive jobs at growing operations – plant spacing. With more technology coming, investing in robots could become even more realistic for growers of all sizes.

Read More

March 2, 2015

Smartpot Uses Sensors And Cartridges To Ensure Success In Growing

Click & Grow helps make it simple for consumers to grow their own herbs and spices at home, even if they have little experience with plants.

Read More
Latest Stories
Rose Rosette on Knockout rose, May 2013. Photo credit: Alan Windham, University of Tennessee

March 2, 2015

Rose Rosette Disease Fight Gets A Boost From Government…

In 2014, $4.6 million was awarded through the Farm Bill to tackle rose rosette disease, a devastating pathogen that affects one of the industry’s most important crops.

Read More
Fig 1 Leafy Gall On Leucanthemum Becky

March 2, 2015

How To Prevent Leafy Gall Before You Lose Plants

Leafy gall is a nasty disease that can go undetected until plant damage is done. Take these steps to protect your crops from infection.

Read More

February 17, 2015

A New Look At Biological Control: Can Plants Affect The…

The success of a biological control program depends on a number of factors including quality of natural enemies, timing of release, release rates and environmental conditions. However, what is typically not taken into consideration is how plants can affect the performance of natural enemies, including attack rate and searching ability. Biological control agents work hard to protect plants, but plants have ways to help themselves, too.

Read More

February 1, 2015

New Pest Control Products For Your Toolbox

Add one of these new insecticides to your IPM program for successful pest control.

Read More
IR-4_profile_Feb2015

January 29, 2015

IR-4: A Pest Management Resource For Growers

Almost 40 years ago, IR-4 (Interregional Research Project Number 4) began serving the ornamental horticulture industry, helping to facilitate the registration of pest management tools. IR-4 does this primarily by surveying growers about their pest management issues and then hosting workshops to review survey results and set priorities for the coming years. Most recently, IR-4 coordinated a meeting of researchers and industry members on pollinator health and neonicotinoid chemistries to start a discussion on the needed research. The next step will be to get the outcomes from that workshop out to the public.

Read More

January 28, 2015

Biocontrols 2015 Conference & Tradeshow: Peace Tree…

Lloyd Traven, a speaker at the upcoming Biocontrols 2015 Conference & Tradeshow, was one of the industry’s early adopters of biocontrols in the greenhouse. Traven, owner of Peace Tree Farm, is evangelical about the technology as an effective tool for resistance management, as well as improved plant quality that contributes to a grower’s bottom line.

Read More

January 27, 2015

Southwest Perennials Improves Production, Shortens Crop…

A father-and-son team find LEDs deliver a higher rooting rate for cuttings propagated under the lights.

Read More
Wainwright-web-620x349

January 22, 2015

Quality Control With Biocontrols

Make sure the shipment of beneficials that just arrived is viable and ready to go to work in your greenhouse, nursery, or field. Here are five steps you can take to ensure success with your biocontrols.

Read More

January 9, 2015

6 New Fertilizer Products For Healthy Plants

These five products add even more options for delivering nutrients to the root zone.

Read More

January 7, 2015

Fertilizers And The Future

As growers look for new ways to cut costs and conserve resources, fertilizer and equipment companies are offering products that strive to save water, reduce toxic runoff and keep chemicals out of the equation.

Read More

December 31, 2014

Gain Greater Control Of Fertilizer With Automated Ferti…

University researchers look at integrating irrigation and fertilization with the help of water sensors to reduce fertilizer treatments and improve application timing.

Read More
As directed by EPA, the bee hazard icon appears in the Directions For Use for each application site for specific use restrictions and instructions to protect bee and other pollinators.

December 9, 2014

Fact Sheet: The Value Of Neonicotinoids To Turf And Orn…

An extensive study of the diverse turf and ornamental industry (“The Green Industry”) reveals that neonicotinoids are the top-rated products used by professionals to control their most important pests in greenhouses, landscapes, lawns, nurseries and trees.

Read More
As directed by EPA, the bee hazard icon appears in the Directions For Use for each application site for specific use restrictions and instructions to protect bee and other pollinators.

December 9, 2014

New Study Finds Neonicotinoids Are Top-Rated Products F…

According to results of a survey by AgInfomatics, professionals in the turf and ornamental industries fear the loss of neonicotinoid products would reduce the quality of their plants and services, increase costs and negatively impact their ability to manage pest resistance.

Read More

December 2, 2014

Grow-Tech Announces BioStrate, Its Newest Hydroponic Gr…

Grow-Tech LLC recently announced the release of BioStrate Felt, a biobased textile specifically engineered for the growing of hydroponic microgreens and baby salad greens.

Read More

November 25, 2014

Former Harris Seeds Co. CEO, Per Jensen, Passes At 85

A passion for plants defined long-time industry influencer.

Read More

November 21, 2014

Ramped-Up Predatory Mite Production To Benefit Growers

Biological pest control company Beneficial Insectary is now producing both Amblyseius (=Neoseiulus) cucumeris and Stratiolaelaps scimitus (formerly Hypoaspis miles) at its facility in California. Domestic production in the U.S. is now benefiting growers in North America by reducing the transit time of perishable predatory mites between producer and grower.

Read More

November 18, 2014

7 New Media And Light Products For Greenhouse Productio…

New media and light products cover a broad sweep of growing conditions.

Read More

November 14, 2014

Skagit Gardens To Eliminate Use Of Neonicotinoid Pestic…

Skagit Gardens, a wholesale grower located outside Mount Vernon, Wash., will eliminate all use of neonicotinoid pesticides beginning in January 2015.

Read More