Registration Considerations for Chemical Bird Repellents in Fruit Crops
Bird damage has plagued orchardists since the earliest times of cultivation. In a matter of minutes, a flock of birds can literally strip a tree of all harvestable fruit or render hanging fruit unmarketable. While this level of damage is rare, signifi- cant economic impact can occur to those orchards where birds select to forage. Crop protection techniques available to orchardists are primarily limited to hazing (scarecrows, propane cannons, flagging) and physical exclusion (netting). Given the propensity of birds to habituate to hazing techniques, hazing methods offer limited protection for crops. Although exclusion devices may offer the best protection from birds, they are expensive to purchase, install, and maintain. As a consequence, orchardists have sought a chemical means of protecting their crops from bird damage. Repellents are, by design, not toxic to the target organism. They may, however, still have undesirable impacts on humans and the environment. Consequently, repellents are subject to the same general registration requirements as traditional agricultural chemicals. As with any chemical application to a food or feed crop, a major hurdle for expanding the use to fruit crops is the establishment of a residue tolerance for applications made during the ripening period. Between 1972 and 1991, fruit (cherry and blueberry) producers in 10 states were allowed to use methiocarb (as Mesurol) to combat avian damage. In 1987, the United States Environmental Protection Agency (US EPA) published the Registration Standard (US EPA 1987), summarizing the data available to support continued use of methiocarb as an avian repellent in corn fields and fruit orchards, and for slugs and snails in ornamental plantings, lawns, turf and ginseng. The US EPA's review concluded that additional product chemistry, residue chemistry, ecological effects, environmental fate, toxicology and occupational/residential exposure data were needed to continue these uses. Because of the cost associated with generating these data, registrants voluntarily cancelled all uses of methiocarb as a avian repellent and EPA subsequently waived the residue chemistry data requirements for the remaining uses (US EPA 1992). Thus, the primary hurdle facing product registration of an avian repellent for agricultural crops is the establishment of a residue tolerance when applications must be made late in the growing season to protect ripening crops. The time between application and harvest is most often insufficient for desired residue decline before reaching the consumer. Since 1992, new chemical repellents have been actively sought to protect agricultural crops, but only one (a.i., methyl anthranilate) has been fully registered with the US EPA. Methyl anthranilate is a GRAS-listed (Generally Recognized As Safe) food additive which is commonly used as grape flavoring. It has been demonstrated to be repellent to birds when consumed (Clark et al. 1991) and currently has 8 active product registrations with the US EPA. In 2002, the US EPA exempted methyl anthranilate from the requirement of a residue tolerance (Federal Register: August 7, 2002 (Volume 67, Number 152)). It is registered for bird control on structures, airports, ornamental plantings, turf, fruit crops (berries, grapes, pomes, stonefruit), and grain crops (corn, barley, rice, sorghum, millet, wheat, oats, sunflower), and can be applied in baits, broadcast application or as a fog. Although methyl anthranilate is currently registered as an avian repellent for use in a variety of food crops, independent research has shown that bird damage did not differ between methyl anthranilate-treated versus untreated blueberries (Cummings et al. 1995, Avery et al. 1996). Additionally, it was not effective for repelling blackbirds from ripening rice and sunflower fields. This paper presents the data requirements and cost considerations for US EPA product registration of a chemical repellent for protecting fruit crops (e.g., cherries, blueberries) from bird damage. Four approaches to product registration for a food use are presented: 1) development of a new active ingredient; 2) registering an existing avian repellent for use in fruit; 3) registering an existing pesticide formulation as an avian repellent for use in fruit crops; and 4) registering a new formulation of an existing pesticide product as a avian repellant on fruit crops.
More about this publication?