Resistance Isn’t Futile — It’s Manageable

It’s high on the list of grower nightmares. An important and reliable pesticide suddenly stops working. It’s a well accepted fact that sooner or later, pests and diseases develop resistance to synthetic chemicals. Now what?

One answer is to switch products. That may help, but the same dynamics would be at play and the problem will likely reoccur. But there is another answer: Confound the pests with strategically timed applications of more complex chemistries.

Complex chemistry is the trademark of biopesticides, which have emerged as the number-one tool in helping growers combat resistance. Biopesticides help manage resistance in two ways. When a grower substitutes a biological for a conventional pesticide, pests and disease populations are no longer being exposed to the synthetic material they’re building resistance to. This extends the efficacy and lifespan of the grower’s most critical synthetic materials. Also, due to their complex chemical nature, pests and diseases do not easily build resistance to biopesticidal compounds.

"The very worst insecticide approach is to find something that works and stick with it," says Dr. David G. Riley, vegetable research entomologist at the University of Georgia, who specializes in resistance management of diamondback moth in brassicas. "And," he adds, "if a product begins to fail, the very last thing to do is reapply the same product."

Growers need alternative materials to supplement their crop protection programs.

Dr. John Trumble, a University of California-Riverside professor of entomology and consultant to some of California’s largest fresh-market tomato, celery and pepper growers, says rotating biopesticides with synthetic chemicals is "absolutely critical."

"We use biopesticides on a regular basis to break the cycle of harder chemicals and try to prevent resistance development," he says. Trumble points out that the growers he consults are very receptive to using biopesticides because "they’ve been stung before by resistance development."

For Trumble, the task of creating a viable rotation program is broader than just recommending crop protection materials. He conducts a cost analysis to determine how to economically rotate biopesticides into the program. "We set up a program and run an economic analysis to find out what the net return was for the compounds that were sprayed," he explains. "That, to me, is the best way to get growers to do it. If a program doesn’t pencil out – show a return on investment – it makes no sense to participate."

Another tool used by both Trumble and Riley is to follow the guidelines outlined by the Insect Resistance Action Committee (IRAC) – an arm of the industry association CropLife – to avoid using materials with similar modes of action, which leads to resistance. Similarly, the Herbicide Resistance Action Committee (HRAC) and the Fungicide Resistance Action Committee (FRAC) have been organized to assist in combating resistance issues in weeds and diseases.

"More and more we are seeing biopesticides being put into conventional programs, and that’s what we’re targeting," says Denise Manker, AgraQuest’s vice president of global development. "The goal," she adds, "is that growers will have more tools longer because they won’t wear out the single-site fungicide." 

Resistance Management

The ability of biopesticides to extend the life of conventional products is rooted in the fact that pests and diseases don’t usually develop resistance to biological products themselves.

John Francis, director of marketing and technical services at BioWorks Inc., Fairport, N.Y., says most synthetic pesticides focus on a specific biological pathway or certain biological functions in the nervous system of an insect and, over time, insects or fungi develop resistance. "Initially the synthetic product works just fine," he says, "but in time, the pest just mutates around it."

Unlike products based on synthetic chemistry, which are usually comprised of a single compound, biopesticides have an active ingredient or formulation that is derived from biological or natural origins. They contain multiple active ingredients and, by extension, are less prone to resistance. Scientifically, it’s incorrect to say resistance will never show up, but the occurrence is low. 

Success In The Field

The most widely used biopesticides for resistance management are Bt- (Bacillus thuringiensis) based products, says Ramon Georgis, global business manager for Valent BioSciences Corp., Libertyville, Ill. Bt is a naturally occurring microorganism in the soil. There are thousands of strains of Bt and a few have been used to manufacture microbial insecticides. "Most of the Bts have multiple toxins," he points out. "Therefore, the opportunity for an insect to build resistance in these types of products is very small compared to most of the chemical insecticides, including the new, reduced-risk insecticides, where, in most cases, there is only one primary mode of action."

As a biological insecticide, Michael Dimock, director of technology and development for Certis USA, Columbia, Md., considers Bt a true success story. He works with products that have proven to make ideal orchard bloom sprays to control twig borer, without harming beneficial organisms such as honeybees, which are usually prevalent in orchards during bloom. By using Bt, the grower achieves the necessary level of pest control, protects the beneficial insects living in his orchard and limits the amount of conventional chemistry being applied.

In tomatoes and leafy vegetable crops, Georgis says that Bt products are also very popular for controlling diamondback moth, loopers and other pests. In one case, relates Georgis, a reduced-risk chemical product was brought on the market to control these pests, but has since been pulled from certain states because diamondback moth quickly became resistant to it. "This is exactly why a Bt product fits ideally in a program with chemical insecticides to expand the life of the chemical insecticides and to minimize the opportunity for the insect to build resistance," Georgis says. Better yield and lower cost to growers have been consistently proven when Bt products are used in resistance management programs with chemical insecticides. This is a valuable and important criterion for growers, Georgis says. The products have to work, and they have to be cost effective.

In greenhouses, biological fungicides have also proven successful for flower growers. In the case of Easter lilies and poinsettias, Francis points out, specific biopesticides have done a very good job controlling pythium root rot, fusarium and rhizoctonia. If a grower is unsure about the health of his cuttings or in cases where disease inoculum gets very high, he recommends coming in with a chemical fungicide drench on the whole crop or just the hot spots, then applying the biologicals. Often, if the cuttings are healthy, no synthetic chemical sprays are needed at all.

The increase in use of biological materials is not limited to crop protection. Michael Braverman, manager, Biopesticide Program, IR-4 Project, Rutgers University, points out that biological materials have a wide variety of applications. As an example, he helped register thymol with the Environmental Protection Agency. Today, thymol has become a popular tool for beekeepers to control varrora mites in honeybees. "The reason," says Braverman, "is that the varroa mites were developing resistance to the conventional miticides." Beekeepers have not reported mites developing resistance to the biological product.

Biopesticides continue to gain momentum as excellent tools to assist growers in keeping resistance under control without sacrificing efficacy or crop quality. 

Leave a Reply

More From ...

April 20, 2015

Three Michigan State University On-Demand Webinars Offer Effective Strategies For Insect And Disease Control On Vegetables

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
Celosia dragon's breath_Sakata

April 20, 2015

Sakata’s Celosia ‘Dragon’s Breath’ Steals The Show In Salinas

Since January, when I first saw celosia ‘Dragon’s Breath’ in the landscape at Costa Farms’ Season Premier, I knew it looked like a great plant that would garner some serious attention. And sure enough, up and down the trials road, people were talking about Sakata’s hot new introduction. Celosia ‘Dragon’s Breath’ is a seed-propagated, plume-type celosia that is said to actually perform better with less fertilizer and water. If it’s fed too much, its dark leaves lose their reddish-purple coloring and turn green, and by restricting water, it tends to bloom more. It tends to be a more vigorous plant than other plume-type celosias, and its large blooms are quite attractive. Sakata also introduced a new series of African Marigolds. Proud Mari comes in Orange, Yellow and Gold, and has huge, fist-sized flowers that bloom vigorously. New colors in SuperCal petunias are L.A. Yellow and Pink, and they are fabulous additions […]

Read More

April 17, 2015

Sakata Seed Uses California Spring Trials Display Plants To Give Back

Sakata Seed America is putting its post-CAST (California Spring Trials) plants and flowers to good use to support events in local California communities of Salinas and Morgan Hill. The plants, along with donations through Sakata's Charitable Giving Program, will support three fun-filled community events that promote healthy lifestyles and support the agricultural industry.

Read More
Latest Stories

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
Celosia dragon's breath_Sakata

April 20, 2015

Sakata’s Celosia ‘Dragon’s Breath’ Steals The Show In S…

Since January, when I first saw celosia ‘Dragon’s Breath’ in the landscape at Costa Farms’ Season Premier, I knew it looked like a great plant that would garner some serious attention. And sure enough, up and down the trials road, people were talking about Sakata’s hot new introduction. Celosia ‘Dragon’s Breath’ is a seed-propagated, plume-type celosia that is said to actually perform better with less fertilizer and water. If it’s fed too much, its dark leaves lose their reddish-purple coloring and turn green, and by restricting water, it tends to bloom more. It tends to be a more vigorous plant than other plume-type celosias, and its large blooms are quite attractive. Sakata also introduced a new series of African Marigolds. Proud Mari comes in Orange, Yellow and Gold, and has huge, fist-sized flowers that bloom vigorously. New colors in SuperCal petunias are L.A. Yellow and Pink, and they are fabulous additions […]

Read More

April 17, 2015

Sakata Seed Uses California Spring Trials Display Plant…

Sakata Seed America is putting its post-CAST (California Spring Trials) plants and flowers to good use to support events in local California communities of Salinas and Morgan Hill. The plants, along with donations through Sakata's Charitable Giving Program, will support three fun-filled community events that promote healthy lifestyles and support the agricultural industry.

Read More
Hakonochloa macra Aureola v

April 17, 2015

Ornamental Grasses — A Few Thoughts

Grasses have been embraced by growers, landscape architects and retailers, and are an important component in wholesale and resale sales. Allan Armitage shares some popular grasses, one to avoid and a few to use with caution.

Read More
PW_CAST15

April 17, 2015

Allan Armitage’s Favorite Plants From Proven Winn…

Between visiting California Spring Trial giants like Proven Winners, Syngenta and Danziger, Allan Armitage saw a lot of great plants in one day. Despite the size of the challenge, Dr. Armitage finds a few favorites he thinks you should try.

Read More
Gazania hybrid 'Amber Ice' (Cultivaris)

April 17, 2015

The 80/20 Theory Approach To Inventory Selection Is Put…

Tim Runte of Calloway Gardens is a member of Greenhouse Grower's Medal Of Excellence For Industry's Choice Panel. Here, he shares how he determines which plants shown at this year's California Spring Trials will make the cut at his retail stores.

Read More

April 17, 2015

Trends At California Spring Trials: AmericanHort’…

Michael Geary, CEO and president of AmericanHort, hit the road during California Spring Trials, and noted trends he saw at many of the stops. Here's one that he says we'll need to consider carefully.

Read More

April 17, 2015

Golden State Bulb At Spring Trials Has Great Appeal For…

While Golden State Bulb is a smaller stop at California Spring Trials, it’s always a treat. You not only get to see less common plants like calla lilies and eucomis, you also get to meet the passionate breeders who developed the plants you’re seeing. For plant geeks, this is a fun stop. First up, the Aloha Lily series of pineapple lily or eucomis was introduced last year, and a new variety, the dark red Kona, joined the lineup. The team at Golden State would like to see this sweet-scented series treated much like orchids by consumers. Like orchids, Aloha Lily does well in low light and has blooms that last two to three months. Now that homeowners have grown accustomed to having orchids, it just may be time to test which other long-flowering plant they would be willing to embrace. Golden State would like to see consumers approach callas in a […]

Read More
PW_calibrachoa_holy moly1

April 17, 2015

Proven Winners Shows Off Its Newest Plant Rock Stars At…

With its wide assortment of plants, great presenters and an amazing location atop a hill at a spa/resort, Proven Winners is a can’t-miss stop during California Spring Trials. The Greenhouse Grower team first visited with Proven Winners’ nursery partner, Spring Meadow, where we got to see the new shrub introductions. Shrubs Proven Winners has two new hydrangea series. The Let’s Dance series is third generation breeding and boasts strong reblooming and a compact habit. The new mountain hydrangea, ‘Tiny Tuff Stuff,’ is another rebloomer and grows to 1.5- to 2-feet tall. Its leaves take on a purple hue when they encounter cool night temperatures. The attractive new Gem Box ilex, an ink berry holly, is suggested as a boxwood replacement for those areas being hit with boxwood blight. It grows to 2- to 4-feet tall and takes full to part sun, but cannot take full shade the way boxwoods can. Spring Meado Nursery  is […]

Read More
Asian-Vegetables-Lettue-Trio-American-Takii

April 16, 2015

American Takii’s Asian Vegetable Line Is Designed…

Unlike many of the other breeders displaying at Spring Trials, American Takii didn’t have many new introductions. But it did have a new program that has prompted many visitors to post to social media — its Asian vegetables. Takii, which is well known for its vegetable breeding, is in the process of vetting the eight to 12 vegetables it will include in the program, and it should have its list fully complete by fall 2015. It is selecting plants that will be easy to use in Asian cooking and will help it stand out from the many vegetable programs in the ornamental market. The Takii marketing team designed bright-red Chinese food takeout containers to act as plant sleeves and a small booklet with five recipes. Honey Chicken With Pak Choy looked especially tasty. Take a look at how the program looks and let us know what you think.       HilverdaKooij is a […]

Read More
HGTV HOME Plant Collection_pre-made succulent container

April 16, 2015

HGTV Incorporates Plants Into Lifestyles And Helps Cons…

When we visited Dummen’s site at Edna Valley Vineyard, the HGTV HOME Plant Collection display was teeming with excited visitors checking out the new varieties, designer mixes and concepts.

Read More
Westhoff_Crazytunia_Swiss Dancer

April 16, 2015

Allan Armitage Finds Some Surprising Intros At Floricul…

Allan Armitage visited three breeders at Spring Trials’ newest location, Floricultura. He found several plants that made Floricultura’s debut a must-stop site in 2015. Westhoff At Westhoff, plant breeding is alive and well, with many things to embrace. The petunia program is vibrant and creative, and I am particularly confident that the Crazytunia program will continue to grow. Crazytunias should fly off the shelves because of their unique colors. Westhoff also brings more standard fare to the table. The Epic series of bacopas have large flowers and should be of particular interest. ‘Epic White’ is particularly nice. And the lobelia in the Hot series has been excellent. ‘Snow White’ adds a good white to the mix. The Hot series does tolerate heat better than most lobelias and now it has a reasonable number of colors. The plant that caught my interest the most this year was ‘Lilac Cascade.’ According to Westhoff, this […]

Read More
westhoff_lilac falls

April 16, 2015

The New Floricultura Stop Showcased A New Interspecific…

Floricultura is a new stop for Spring Trials that hosted Westhoff, Beekenkamp and Plug Connections. It is a welcome addition to the California tour, offering a backdrop of an impressive high-tech greenhouse with orchid production underway within a few feet of the Trial displays. Westhoff The first breeder the Greenhouse Grower team toured, Westhoff, is a relative newcomer to CAST. This German company brings its storied European history of breeding plants (it’s a more-than-100-year-old company) to the U.S. Here in the U.S., Westhoff is best known for its Crazytunia series of petunias, with its vivid and sometimes unexpected colors. It introduced eight new varieties in the series, with ‘Limy’ and ‘Cherry Cheesecake’ getting some pointed attention from attendees. The Hot series of lobelia captured a lot of attention. These lobelias are tested in Florida, Texas, California, Michigan and Colorado, and offer more toughness than we are used to seeing from this genus. The […]

Read More

April 16, 2015

Golden State Bulbs And Sakata: Allan Armitage Highlight…

Dr. Allan Armitage was excited to see both new and improved breeding, as well as have the chance to meet breeders and talk shop at Sakata Seed and Golden State Bulb. Sakata Seed At Sakata, we wandered through traditional crops like zinnias, New Guinea impatiens, calibrachoa and petunias. However, I have always been impressed with the SuperCal program, and this year’s introduction of vibrant colors of Light Yellow and Pink really caught my eye. The flowers of Light Yellow are significantly larger than other colors in the series. I believe the SuperCals are poised for major additional sales. Everybody was talking about ‘Dragon’s Breath’ celosia, and I wanted to see what the hype was all about. It is surely hype-worthy. The plants I observed were large with obvious vigor, and the foliage was coppery with huge, bright, rose-red flowers. Apparently this is a plant that benefits from minimal inputs, such as […]

Read More

April 15, 2015

Redesigned SunPatiens Website Offers New Tools For Saka…

Sakata Seed America's new and improved SunPatiens website launched March 1, 2015 and provides growing information, marketing support, product location and many more tools to encourage consumer success with SunPatiens.

Read More
Farwest2015

April 15, 2015

Online Registration For FarWest 2015 Open, Discount Bef…

Online registration is now open for FarWest 2015, a green industry educational conference and tradeshow, which will take place August 27 to 29 in Portland, Ore. The show promises a full menu of classes, seminars and off-site events, plus a special benefit added this year for attendees.

Read More
Dummen_SunStandingseries_Salmon Pink1

April 15, 2015

Dümmen Group Updates Confetti, Debuts New Mixes And Con…

At two separate locations, the Dümmen Group presented its new take on several lines of plant genetics from the many companies under its brand umbrella. For the second year at Edna Valley Vineyards in San Luis Obispo, the Dummen Group presented new varieties of Red Fox plants, along with the HGTV HOME Plant Collection. Meanwhile, Dummen Group held its second trial location about 30 minutes up the road, at BarrelHouse Brewery in Paso Robles. Both locations were beautiful settings, but the vineyard provided especially lovely panoramic views through the tasting room window.

Read More
CAST15_Suntory_Soiree1

April 15, 2015

McHutchison’s Vaughn Fletcher Reviews New Offerin…

Vaughn Fletcher with McHutchison Horticultural Distributors is part of Greenhouse Grower's Medal Of Excellence For Industry's Choice Panel. Fletcher recounted some of the standout varieties he saw while visiting Suntory Flowers and Westhoff during California Spring Trials.

Read More