Silverleaf whitefly.
Silverleaf whitefly.

Growing Matters is releasing two new case studies on the effectiveness of neonicotinoids on pest management.  The first is about the invasive silverleaf whitefly in ornamentals.  Neonics are a critical tool in controlling this insect that has had devastating effects, including costing growers hundreds of millions of dollars in losses in a single season.  The second is on the impact of the chinch bug in the turfgrass and lawn care industry. Not having access to neonics can cripple lawn professionals’ ability to control this rapidly reproducing bug that has become resistant to many commonly used insecticides.

A recent investigation of the impact of the silverleaf whitefly on nursery and greenhouse plants shows that neonicotinoid insecticides are the cornerstone of integrated pest management (IPM) programs to control this invasive pest.  A case study of the floriculture and greenhouse industry confirms that IPM strategies are essential to help protect ornamentals – as well as agricultural crops – from this destructive pest, which has been shown to cost growers hundreds of millions of dollars in losses in a single season. 

The U.S. Department of Agriculture (USDA) has estimated that nursery and floriculture crop receipts total $11 billion annually in the United States, and according to the University of Florida’s Institute of Food and Agricultural Sciences, account for 436,000 jobs. Many floriculture plants and rootstocks are imported to the United States for further production before being redistributed to domestic and international suppliers.  The widespread movement of plants in this industry makes the prevention of invasive species a key management concern.

Silverleaf Whitefly

Of the many pests affecting ornamentals, perhaps none is as important as the silverleaf whitefly, an invasive species that is also a major pest and disease vector in many agricultural crops.  Because of its ability to feed on many plant hosts, formation of unique biotypes and prolific reproductive capability, resistance development in this insect is extraordinarily high.  Following the introduction of one strain of this pest and the subsequent development of resistance to several common insecticides, losses of $500 million were reported in four states during a single year.  For this reason, producers need a fully integrated management approach to keep populations below damaging levels.

Modern neonicotinoids are considered an essential component of today’s IPM programs to manage silverleaf whitefly.  Many producers worry what the loss of these products would mean to their pest management and business operations. “Without neonics as an option, the alternatives just aren’t there, and we run the risk of developing resistance to the few systemic tools we have” noted Tom Wheeler, Director of Growing Operations for Bell Nursery.

Neonicotinoids offer several major advantages over other products used in greenhouses and nurseries. They can be applied to the soil where the insecticide is absorbed by the roots and moves systemically within the plant. Or, they can be applied as a foliar spray, where the product moves within the leaf by translaminar action to reach the whiteflies feeding on the undersurface.  Neonicotinoids are used at low rates, provide long-lasting protection and have less impact on beneficial insects, thereby reducing the volume and frequency of overall insecticide use and helping to minimize potential worker exposure.

Because of these performance benefits, the industry relies on neonicotinoids to control and prevent the spread of invasive and quarantine pests (and the diseases they transmit) both domestically and internationally, while meeting the high quality standards required by consumers.  Without these products, existing quarantine requirements for pests would mean that some nurseries and greenhouses could lose the ability to sell into certain restricted areas.  Neonicotinoids remain a key component of pest management both in the U.S. and abroad.   The loss of these products would negatively impact existing IPM practices and cause a serious disruption in plant trade.

Chinch Bug

A new case study investigating the management of the southern chinch bug in Florida St. Augustinegrass has shown that neonicotinoid insecticides are critical tools for homeowners and lawn care professionals to protect turfgrass from this destructive pest.  Without neonicotinoids, the use of integrated pest management (IPM) practices would be severely restricted, increasing the likelihood for pest resistance and the potential for significant economic losses to homeowners and those managing southern lawns.  

According to a study conducted by the University of Florida in 2006, the U.S. turfgrass industry is responsible for about 823,000 jobs, with a total financial impact of nearly $58 billion.  In Florida alone, this industry has an economic impact exceeding $3 billion and provides for more than 80,000 jobs.

A healthy lawn is more than aesthetically pleasing, it also provides significant environmental benefits, including soil stabilization, storm-water retention, carbon sequestration, and reduced cooling costs in the summer.  There is broad interest in managing lawns sustainably to help support water management and “Florida-friendly landscaping” that are explicitly recognized by Florida statute, which emphasizes the importance of managing pests with chemical controls where appropriate.

St. Augustinegrass is among the most common residential lawns in Florida and the southern United States, especially in areas along the southern coastline.  The southern chinch bug is the predominant insect pest and a significant management problem in St. Augustinegrass.  Although chinch bugs are very small, they can cause severe damage to lawns by sucking fluid from turfgrass over successive generations produced each year.  Their ability to reproduce rapidly has helped these pests develop resistance to many commonly-used insecticides.

Management of chinch bugs includes biological, cultural and chemical practices.  Although biological controls, such as natural predators are helpful, they typically are not sufficient to suppress the rapid reproduction of these pests.  Neonicotinoid insecticides have become an indispensable component of integrated pest management (IPM) programs in turfgrass because they are very effective against chinch bugs and are less disruptive of beneficial insects when compared to other less-selective insecticides.

Many lawn service professionals prefer neonicotinoids, which they consider to be safe and effective alternatives to some older insecticides and because they have less impact on the beneficial insects which help keep chinch bug populations in check.  According to Adam Jones, Vice President, Director of Quality Assurance for Massey Services, “We have always practiced IPM to protect beneficial insects and to manage for resistance. Without neonics, managing chinch bugs will require significantly more pesticide applications.”

If neonicotinoids were not available, homeowners and lawn service professionals would be left with fewer management options and no effective chemistry rotation.  “Pyrethroids are not enough to protect lawns.  Greater use of organophosphates and carbamates is a major step backwards,” said Dr. Eileen Buss, Associate Professor & Extension Turfgrass Entomologist at the University of Florida.  “If we lost neonicotinoids for chinch bug management in Florida, we would lose the only really effective chemical class with which to rotate and mitigate insecticide resistance.” 

With fewer chemical alternatives, the potential for serious damage to turfgrass greatly increases. When maintenance and treatment fail to prevent chinch bug damage, St. Augustinegrass must be removed and replaced at a cost that can reach up to $1,000 per thousand square feet of lawn, an expensive proposition for most homeowners. Some lawn care service companies have guarantees to replace damaged turf if treatments are not successful and fear the loss of neonicotinoids would jeopardize existing contracts and add considerable expense to their business operations.  As Adam Jones summarized, “without neonics as a management tool, I don’t think the market could continue to offer those guarantees to new customers.  Without neonics, lawn replacement costs would skyrocket.”