Taking Out Spider Mites

Taking Out Spider Mites

Two-spotted spider mite, Tetranychus urticae, is still one of the most destructive mite pests of greenhouse-grown crops. Because it is so destructive, greenhouse producers use miticides to alleviate problems and avoid excessive mite outbreaks. Several commercially available miticides are called mitochondria electron transport inhibitors, or METIs, which disrupt the production of energy or adenosine triphosphate (ATP).  

But before any specifics are addressed, it’s important to note the significance of the mitochondria. The mitochondrion is a membrane-bounded organelle that is associated with intracellular respiration. It is a major site of ATP production and oxygen consumption in cells, and it retains enzymes involved in the citric-acid cycle and in oxidative phosphorylation.

Overview

Miticides active on mitochondria include acequinocyl (Shuttle), pyridaben (Sanmite) and fenpyroximate (Akari). These miticides either inhibit NADH dehydrogenase (complex I) associated with electron transport, act on the NADH-CoQ reductase or bind to the Qo center or cytochrome bc1 (complex III) in the mitochondria. 

This leads to a reduction in energy production by preventing the synthesis of ATP. The basic difference among these miticides is the target site. Shuttle works on complex III, whereas both Sanmite and Akari work on complex I. In addition, the strobulurin-based fungicides such as azoxystrobin (Heritage), kresoxim-methyl (Cygnus) and trifloxystrobin (Compass O) are considered mitochondria electron transport inhibitors and are active on complex III in the mitochondria of many different fungi.

Although spider mites and fungi are different organisms, we thought it would be interesting (as researchers) to determine if these types of fungicides actually have miticidal properties. In fact, certain fungicides have shown to negatively impact spider mites.

For example, the benzimidazole fungicide benomyl (Benlate) actually inhibits the development of spider mites directly, as well as reducing female fecundity. However, the strobulurin-based fungicide trifloxystrobin (Compass) does not appear to have any harmful effects on female two-spotted spider mites. As such, we wanted to pursue this further, so we conducted a study to simultaneously evaluate the efficacy of both mitochondria electron transport inhibiting miticides and fungicides against the two-spotted spider mite.

Materials and Methods

Marigold ‘Antiqua Yellow’ plants were transplanted into 1.0-quart (0.9-liter) containers filled with Fafard 3B growing medium (peat moss, perlite, vermiculite and processed pine bark). No pesticides had been applied to the test plants before conducting the study. 

The test plants were placed in a research greenhouse to allow a “natural” population of two-spotted spider mites to build-up. The treatments and rates are presented in Table 1. There were five replications per treatment. Treatments were applied using a fine mist spray bottle with the plants approximately 12 inches in height at the time of application.

After application of the treatments, the test plants were placed into another research greenhouse on a wire-mesh raised bench and arranged in a completely randomized design. One plant was equal to one replicate. The temperature ranged from 87 to 72ºF (30 to 22ºC) with a relative humidity between 50 and 90 percent. Test plants received natural lighting during the course of the study. All marigold plants were watered with a handheld sprinkler. There was no overhead irrigation in order to avoid washing off any two-spotted spider mites.

Plants were evaluated before application of the treatments (precount). They were also evaluated three, seven and 14 days after treatment (DAT). Four leaves were randomly selected and harvested from each plant. The number of live and dead nymphs, and live and dead adults of two-spotted spider mites were recorded. The precount reading was performed to ensure the test plants had similar populations of two-spotted spider mites so that any effects were solely due to the treatments and not confounded with variable numbers of two-spotted spider mites on the marigolds. All data was subject to analysis using a statistical program in SAS (Statistical Analysis Software).

Results

None of the METI fungicides evaluated provided any control of two-spotted spider mite nymphs or adults, whereas the three METI miticides eventually resulted in some level of control of two-spotted spider mite nymphs 14 days after treatment.

However, the miticides were only slightly effective against two-spotted spider mite adults with less than 70 percent mortality among all three miticides across the three evaluation periods–three, seven and 14 days after treatment. Judo (spiromesifen) was very effective against both the nymphal and adult stage of two-spotted spider mite with greater than 95 percent mortality across all three evaluation periods for nymphs and greater than 70 percent mortality across the three evaluation periods for adults.

The miticide Ovation (clofentezine) failed to control both life stages (nymphs and adults) of the two-spotted spider mite. This is likely due to the fact that Ovation is an ovicide (egg killer), with activity primarily on spider mite eggs.

The fungicide Cygnus (kresoxim-methyl) had a somewhat marginal effect on both life stages (nymph and adult) with mortality values greater than 10 percent seven and 14 days after treatment for nymphs, and 14 days after treatment for adults.

It appears due to the specific mode of action associated with fungi, the strobulurin-based fungicides will have negligible if any negative effects on the metabolism and/or population growth of two-spotted spider mite based on the results of the study.

Leave a Reply

More From Insect Control...
Cultivate'14 GG and TGC Booth

July 7, 2015

Join Greenhouse Grower And Today’s Garden Center At Cultivate’15

Greenhouse Grower and Today's Garden Center are excited to take part in Cultivate'15. We have a lot going on in our booth, and we hope you will be there to join us as we celebrate careers in horticulture and honor the industry’s top growers, breeders and marketers.

Read More
BeeSmart logo

July 7, 2015

Grow Wise, Bee Smart Website Launches As Industry Resource On Pollinator Health

The new Grow Wise, Bee Smart website, growwise.org,  was recently launched as a key component of the horticulture industry’s Bee and Pollinator Stewardship Initiative, which was created to provide leadership and guidance to the industry on pollinator health. The site serves as the communications hub for the latest research and developments related to the role horticulture plays in supporting pollinator health. Grow Wise, Bee Smart currently features information on the importance of bees and pollinators, threats to their health and steps everyone can take to improve habitat and forage. Links to the Million Pollinator Garden Challenge and Pollinator Partnership further guide retail and landscape firms and their customers on how to plant and register new gardens and habitats for pollinators. As the Grow Wise, Bee Smart stewardship program for plant production is launched, and as funded and directed research yields results and guidance, the site will feature timely new information and insights. Progress […]

Read More
The-Capitol

July 7, 2015

Washington Gridlock Could Block Industry Research Funding

The latest standoff on Capitol Hill could have some implications for the floral industry, including future funding for floriculture and nursery research initiative activities, says Shawn McBurney, SAF’s senior director of government relations. “Republicans in the House and Senate are determined to work within the sequester-imposed limits for domestic spending in the federal budget, but Democrats have threatened to block any appropriations bills until Republicans agree to spend more money than that agreement allows,” McBurney says. “With both sides digging in, there could be an impact on budgets that affect programs and services important to the floral industry.” The back and forth over spending limits isn’t new, McBurney says. In 2013, then-Budget Committee Chairmen Paul Ryan (R-Wisc.) and Patty Murray (D-Wash.) negotiated an agreement that increased spending levels for defense and nondefense discretionary spending equally above the sequester level for two years, offset by fee increases and changes to mandatory […]

Read More
Latest Stories
Feature image The Aphid Guard Aphid Banker Plant, coming soon to the market, supports beneficial insect populations.

June 21, 2015

The Latest In Crop Protection

Protecting your plants from the latest threats is no easy task, but new product lines promise to safely and effectively eliminate a wide range of pests and diseases, without harming your employees or the environment.

Read More
Bee On Flower

June 18, 2015

Pest Management And Marketing Strategies For Bee-Friend…

Michigan State University Extension shares pest management practices to produce plants that are safe for pollinators and marketing strategies for clearing up confusion about bee-friendly plants.

Read More

June 10, 2015

BASF’s Sultan Miticide Receives California Regist…

BASF Sultan miticide recently received registration in California, giving ornamental growers a new rapid, targeted mode of action for mite control. Sultan miticide, with active ingredient cyflumetofen, offers ornamental growers targeted knockdown of all life stages of tetranychid mites, with long residual control. It has practically no toxicity to beneficial insects, including predatory mites and pollinators. Sultan miticide offers a new mode of action to combat cross-resistance with other commercial miticides, and is compatible with integrated pest management programs (IPM). “The long-awaited California registration of Sultan miticide is exciting news. Greenhouse, nursery and landscape professionals in the state now have a new class of chemistry that gives them fast control over all life stages of plant-damaging mite populations,” says Joe Lara, senior product manager for BASF. “Sultan miticide now provides California growers with a much needed new first choice for miticide resistance management programs that won’t disrupt populations of beneficial […]

Read More
Bee On Flower

May 20, 2015

White House Task Force Releases Pollinator Health Strat…

An interagency Pollinator Health Task Force commissioned by President Obama released its “Strategy to Promote the Health of Honey Bees and Other Pollinators” on May 19. The strategy, released in accordance with the Presidential Memorandum issued last June, is accompanied by a Pollinator Research Action Plan, which outlines needs and priority actions to better understand pollinator losses and improve pollinator health. The recommended actions will be supported by a coordination of existing federal research efforts and accompanied by a request to Congress for additional resources to respond to losses in pollinator populations. Pages 47 through 52 specifically address pesticides and pollinators. The report calls out plant production, native plants, mosquito control and all urban uses in its Pollinator Action Plan. RISE (Responsible Industry for a Sound Environment) says it supports the goals of improving pollinator health and habitat contained in the White House Pollinator Task Force’s release of its National […]

Read More
Two-spotted spider mites, adults and eggs

May 18, 2015

Beware Of Spider Mites In Bougainvillea And Mandevilla …

Greenhouse growers need to scout for spider mites on bougainvillea and mandevilla and use appropriate treatments that minimize pesticide resistance.

Read More
CrownBees_Blue-Orchard-Bee-Female_Artz

May 14, 2015

Pollinator Health 2015: What’s Next For Horticult…

The news on pollinators and neonicotinoids continues to fluctuate between good and bad. Research and outreach efforts backed by the Bee and Pollinator Stewardship Initiative help move the industry in a positive direction.

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
Surendra Dara told attendees that biopesticides aren’t just for organic production. “These are tools for conventional growers, too. These materials do work.”

April 14, 2015

Biocontrols Are Covered In Depth At Biocontrols 2015 Co…

More than 400 growers, pest control advisers and certified crop advisers, researchers, government regulators and suppliers gathered in Fresno on March 3-5 for the Biocontrols 2015 Conference & Tradeshow. This event — a first of its kind focused solely on the use of biopesticides and other biocontrols — brought attendees together for an in-depth discussion on the latest tools available, “how-to” production topics, market trends and regulatory issues. Attendees also spent time with nearly 40 exhibitors learning about new technologies, techniques and services bringing biocontrols into the mainstream with growers all over the country. “Ours is a very economic and science-based business culture,” said Gary Schulz, the new CEO of the California Association Of Pest Control Advisers. “We encourage our pest control advisers (PCAs) to use all of the tools they have available, traditional chemicals, as well as many of the new softer materials including biopesticides and biocontrols.” Sessions covered […]

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
Restricting foliar pesticide applications on blooming plants to early morning or as dusk approaches in the evening reduces direct exposure to bees.

April 10, 2015

10 Steps For Protecting Crops And Bees

Bees stay safe and high quality crops thrive when you use bee-friendly practices designed to help both succeed. Griffin Greenhouse Supply Pro (GGSPro) has been actively discussing bee-friendly pesticide use for years. Based on its current understanding of the science and social factors at play, GGSPro currently recommends these 10 bee-friendly practices.

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.

April 8, 2015

AFE To Fund Honey Bee Health Research Focused On Transl…

The American Floral Endowment (AFE) is funding a new research project to examine the health of honey bees on ornamental plants following treatment with neonicotinoids and other systemic insecticides.

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
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
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