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...
PP&L CAST 2015 intros

April 22, 2015

6 Breeding Companies Serve Up New Varieties At Pacific Plug & Liner

Pacific Plug & Liner’s theme this year, Labyrinth, a conservatory of the world’s most captivating plants, was perfectly topped off (pun intended) with fascinators for the women and newsboy caps for the men. The PP&L team dressed their part to act out the gothic “conservatory of the world’s most captivating plants.” Truly, the displays looked like they practically popped out of a catalog, and the costumes were a nice touch. Retailers take heed, the fully merchandised displays at Pacific Plug & Liner are worthy of emulating. We’ll let the pictures tell the story of all the fabulous variety introductions presented at  Pacific Plug & Liner’s 2015 California Spring Trials, where Cultivaris, Cohen Nurseries, Histil Nurseries, Jaldety Nurseries, Southern Living/Sunset Collection and Pacific Plug & Liner all highlighted their 2016 introductions.  

Read More
Speedling 2015 CAST intros

April 22, 2015

Speedling Inc. Presents New Varieties From ABZ Seeds, Hem Genetics, Thompson & Morgan, Vista Farms & PSI

You name it, we saw it at Speedling's California Spring Trials location in San Juan Bautista, where five companies showed off their new introductions for 2016.

Read More
PittMoss on Shark Tank

April 22, 2015

PittMoss Wins On Shark Tank

Mont Handley, president and CEO of PittMoss, appeared on ABC’s Shark Tank on April 17 to try to get the “sharks” to invest in his peat moss alternative. Three investors from the TV show contributed $600,000 to PittMoss for a 35 percent stake in the company. Check out this clip from ABC’s website in which Mark Cuban, Kevin O’Leary and Robert Herjavec discuss getting on board with the product. PittMoss is an alternative to sphagnum peat moss, made up of a mix of proprietary additives and recycled paper rescued from landfill space. Handley founded the Pittsburgh-based company in 1994. What started as a small experiment grew into a full-fledged business with the help of funding provided by an EPA SBIR grant and Pittsburgh’s Idea Foundry. Today, PittMoss is available to commercial greenhouses and nurseries from Michigan to Maine to North Carolina, with plans to grow. To learn more, visit PittMoss’ website, or check it […]

Read More
Latest Stories
Green Mum Basket

April 21, 2015

Growers Face Dilemma In Managing Plant Growth

Whether you’re applying plant growth regulators, manually pinching plants or using automated trimming, the most important thing is to find the right balance.

Read More

April 20, 2015

Three Michigan State University On-Demand Webinars Offe…

The first rule of effective insect and disease control for vegetables is to take action to prevent problems before they occur. But in order to do that, you need to have an effective pest and disease management strategy in place that incorporates best practices to ensure a successful outcome. Michigan State University offers three pest and disease management on-demand webinars that will get you started and keep you on the right track.

Read More

April 15, 2015

BASF’s Pageant Intrinsic Fungicide Registration A…

The state of California has approved the supplemental label registration of Pageant Intrinsic brand fungicide for disease control in the commercial production of greenhouse-grown tomatoes and tomato transplants for the home consumer market.

Read More
Egg card used for insect control in Parkway Garden’s retail area.

April 13, 2015

Biocontrols Use Requires Commitment

For some companies, a switch to biocontrols is an easy decision to make. Parkway Gardens of Ontario, Canada, began using biocontrols nine years ago after Erik Jacobsen, the company’s owner, wanted to expose Parkway, its customers and the environment to fewer pesticide products. “Many pesticides were increasingly ineffective, and in Canada, new product registration moves with glacial slowness,” Jacobsen says. “The labor cost of applying pesticides is much greater than using biocontrols.” In addition, it was also an opportunity to market the company’s eco-friendliness to a younger demographic, he says. In a Q & A with Greenhouse Grower, Jacobsen explains what biocontrols and methods have proved effective for Parkway Gardens Greenhouse Grower: In what types of greenhouse structures are you using biocontrols? Erik Jacobsen: Our greenhouses are all poly covered. About half the range is a Westbrook 14-foot at peak gutter-connected block, and the remaining half a mix of quonset-style […]

Read More

April 11, 2015

Lowe’s Announces Commitment To Phase Out Neonicotinoids…

Home improvement retailer Lowe’s companies announced April 9 that it has committed to eliminate neonicotinoid pesticides from its stores in a gradual phase-out over the next 48 months. In response, horticulture industry associations issued a statement that Lowe’s position is surprising, considering the most recent and positive reports on the state of honeybee health and recent peer reviewed research, and that this is an issue for which sound science must take priority.

Read More

April 9, 2015

Survey Snapshot Shows Biocontrols Mainstreaming

Have you incorporated biocontrols into your greenhouse operation? If so, you’ve got plenty of company. An anonymous online survey by Greenhouse Grower magazine in December 2014 of more than 156 ornamental plant and flower growers across the U.S. found 81 percent used biocontrols in 2014.

Read More

March 31, 2015

Manufacturers Are Taking Biologicals To The Next Level

Through acquisitions and new products, many crop protection companies are making firm commitments to the future of the biocontrols industry.

Read More
OxiPhos_BioSafe2

March 23, 2015

BioSafe Makes Label Changes To OxiPhos And ZeroTol 2.0

There have been some recent label changes made to the BioSafe Systems product OxiPhos, a systemic bactericide/fungicide that reduces downy mildew spores when tank mixed with ZeroTol 2.0.

Read More
Nufarm_logo

March 23, 2015

Nufarm Fungicides Now Registered For Use On Edible Crop…

Nufarm Americas announced label expansions for two of its fungicides that will provide more pest management options for the ornamental industry. The Cleary 3336 F and EG fungicides are now registered for use across a wider range of edible crops, including select greenhouse vegetables and transplants, herbs and backyard fruit.

Read More
ColeusDMLeafSporulation_Daughtrey

March 11, 2015

Research Gives Clues For Preventing Coleus Downy Mildew

Maintaining awareness of coleus downy mildew is more important than ever to safeguard these attractive plants for reliable garden performance.

Read More
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