Zeroing In On Invasives
Researchers join forces to identify best practices for today's most problematic pests.
June 11, 2008
When American patriot Benjamin Franklin warned, "Never leave that till tomorrow which you can do today," he was not thinking of fighting such invasive pests as chili thrips or Q-biotype whiteflies. Yet his words ring very true in 2007 as leaders in the greenhouse and ornamental industries are joining together to identify and address tomorrow's pests today.
The topic of "invasive" or "exotic" pests became central to the discussions among researchers at the annual Valent Professional Products Pest Management Conference held in Wyoming. A host of weed scientists, entomologists, pathologists and industry leaders met to discuss trends and issues important to greenhouse and ornamental growers. Topping their concerns was the rapidly expanding list of invasive pests and ways growers, propagators, researchers and industry members can work together to fight them.
Though some native populations may explode due to human- or weather-related influences, invasive pests are most often classified as "non-indigenous species that adversely affect the habitats they invade economically, environmentally or ecologically." Invasive weeds can outcompete native plants, and invasive pathogens and insect pests are often very detrimental because they lack natural enemies. The results are often devastating to local and regional ecosystems.
Though greater attention has been given to a recent flurry of invasive pests, researchers warn the prevalence and costs of invasive pests are nothing new.
"You only have to look to kudzu in the South to see what can happen when a non-native species is introduced into a new environment," says Dr. Charles Gilliam, horticulturist and professor at Auburn University. "If not managed properly, an invasive species can quickly take over and become almost impossible to eradicate or even contain."
Additionally, with so many new and emerging invasive pests arriving each year, it becomes difficult for many greenhouse and ornamental operators to keep track of, much less manage, these pests within their facilities.
Experts agree that with more globalization - both from human travel and commerce - the potential for additional invasive pests in the greenhouse and ornamental industry will only increase. For example, conference attendee Dr. Catherine Mannion, entomologist and professor at University of Florida, IFAS Tropical Research & Education Center in Homestead, explains she has seen an increase in invasive pests in Florida. Many of these pests arrive via national and international shipments of plant material, she says. Florida has a mild, subtropical climate that is not only very attractive to visitors, but is also very conducive to the establishment of new pests.
"We've gotten an increasing number of calls from growers who have new pests invading their operations," Mannion says. "Top of mind right now are chili thrips, asian citrus psyllid, cycad aulacaspis scale and pink hibiscus mealybug."
Taking A Lesson From Q
But according to researchers at the conference, all is not lost.
Experts agree that proactively addressing the shipment, identification and treatment of invasive species may go a long way to helping growers. Many point to the Q-biotype whitefly as a good, in-progress case study to tackling an invasive pest.
In late 2004, a new insecticide-resistant whitefly - the Q biotype - was detected for the first time on ornamental crops in the U.S., and some growers reported control failures. An initial fear erupted throughout greenhouses in affected states. But leaders from universities, industry, the government and production banded together to determine the most effective pest management tools, set up a system where growers could get whiteflies biotyped and educated growers about how to manage pesticide resistance
The result? There were significantly fewer confirmed Q-biotype appearances in the 2006 season - a factor many attribute to the proactive cross-commodity collaboration developed to proactively address the pest.
Addressing Tomorrow's Invasive Pests Today
To help combat invasive pests, industry leaders are working at national and international levels on such issues as global inventory controls, information sharing and better resistance management practices within shipping and retail operations. Yet with the human factor playing such a large role in dispersion of invasive pests, greenhouse and ornamental operators are often on the front line of the battle. Researchers offer the following tips for growers hoping to join the fight against invasive pests:
1) Scout heavily
The key to any good insect control program starts with a healthy scouting effort. Experts agree this step is especially critical for identifying non-native pests and for making timely pest management decisions.
Mannion says scouting becomes even more important when shipping or moving plant material to other areas, whether it is local, regional or international.
"Although scouting prior to shipment is very important, it is essential that scouting become a regular management practice so new pests are quickly identified and dealt with before they are potentially spread to new locations," Mannion says. "It becomes an industry problem if we don't all work together to keep these materials contained."
Gilliam, who has seen a recent influx of a new weed called liverwort in his area, encourages growers to note any pest that seems out of the ordinary.
"We're definitely not trying to scare growers - it's not a matter of just one little weed showing up and growers asking, 'How do I deal with it?'" Gilliam says. "But suddenly, if a grower starts seeing something unusual more and more often, he needs to know there are a host of resources available and should immediately seek help before the problem gets out of control on his operation or beyond."
2) Include your local researcher/Extension agent
Most of the conference attendees claimed more of their responsibilities are shifting to Extension work and to actual hands-on efforts to help the growers improve production. This collaboration between researcher and grower becomes more important as invasive pests emerge in an area.
Growers should alert their local Extension agent or university researcher at the first sign of an unidentified or unusual pest, says Dr. Michael Benson, plant pathologist and professor at North Carolina State University.
"The National Plant Diagnostic Network was established to enhance national agricultural security, to help researchers collaborate on local and regional pest information and share known best management practices to address various problems," Benson says. "When a grower consults a diagnostic lab on an emerging pest issue, that lab diagnostician has access to an extremely comprehensive pest knowledge base through the NPDN network, so the researcher is better equipped to help manage the pest issue."
Each of the researchers has spent a lot of time on the road this year, meeting with and speaking to growers and other researchers across the country about pest management programs, including those for invasive pests.
"The key for the grower is to tap into that network of knowledge," Mannion says. "Sometimes growers are hesitant to reach out to us for fear of regulatory issues. But if they don't manage the problem quickly, it is only going to be more problematic down the road - for everyone."
3) Rotate chemistries
Pesticides are the first defense in pest control, and several of the newer chemistries, such as Safari and Judo, are very effective against many invasive pests like the Q-biotype whitefly. But some pests such as Q-biotype whiteflies, two-spotted spider mites and western flower thrips are characterized by their ability to develop resistance to insecticides. In some cases the appearance of a new invasive pest can trigger panic among growers, and an over reliance on one or two effective products.
"Overusing one or two products can lead to resistance, which in turn can decrease a grower's ability to manage that invasive pest," says Joe Chamberlin, field development specialist with Valent. "Growers need to conserve those 'best-in-class' products by rotating in other chemistries to their pest management program. A good example of this approach is the Whitefly Management Program developed by the Q-biotype task force."
Gilliam agrees that growers need to implement good resistance management programs centered around rotating modes of actions.
"Understandably, most growers want to put out the cheapest product available over and over and think they are controlling their pests, but you really have to look at the long term," Gilliam says. "Yes, you may pay less for a material upfront, but in the long run, you'll likely pay more for labor to handle the hand weeding of the escapes, and, of course, you're building the perfect situation for resistance. Rotating chemistries is a must for any grower today."
Benson says an alert, educated grower base will benefit the entire industry in the fight against invasive pests.
"Growers in a non-infected area often become more educated on the best practices and potential regulatory issues by watching what their peers in regulated areas must do to ship their materials," Benson says. "This awareness is a very good thing, helping growers implement the best practices in an operation before any problems have even developed."
Emily Dahlbeck is an account supervisor at Archer Malmo. You can reach her at firstname.lastname@example.org.