Application strategies for an anthraquinone-based ...

1 Crop Protection 59 (2014) 63e70. Contents lists available at ScienceDirect Crop Protection journal homepage: Application strategies for an anthraquinone - based repellent to protect oilseed sun ower crops from pest blackbirds Scott J. Werner a, *, Shelagh K. Tupper a, Susan E. Pettit a, Jeremy W. Ellis a, James C. Carlson a, David A. Goldade a, Nicholas M. Hofmann a, H. Jeffrey Homan b, George M. Linz b a United States Department of Agriculture, Animal and Plant Health Inspection Service, Wildlife Services, National Wildlife Research Center, 4101 LaPorte Avenue, Fort Collins, CO 80521-2154, USA. b United States Department of Agriculture, Animal and Plant Health Inspection Service, Wildlife Services, National Wildlife Research Center, North Dakota Field Station, 2110 Miriam Circle, Bismarck, ND 58501-2502, USA. a r t i c l e i n f o a b s t r a c t Article history: Non-lethal alternatives are needed to manage the damage caused by wild birds to oilseed sun ower Received 3 September 2013 crops (Helianthus annuus Linnaeus).

2 We evaluated eld residues and experimental applications of an Received in revised form anthraquinone - based repellent (active ingredient 50% 9,10- anthraquinone ) to minimize red-winged 27 January 2014. blackbird (Agelaius phoeniceus Linnaeus) depredation of oilseed sun ower. Chemical residues from Accepted 31 January 2014. experimental applications of the anthraquinone - based repellent ( l/ha and l/ha; low, high) in a ripening oilseed sun ower eld were 481 ppm and 978 ppm anthraquinone at the beginning of Keywords: blackbird damage, and 385 ppm and 952 ppm anthraquinone at the end of blackbird damage, respec- Agelaius phoeniceus anthraquinone tively. Prior to harvest, we observed 402 ppm and 462 ppm anthraquinone in the oil, and 27 ppm and Chemical repellent 165 ppm anthraquinone in the pomace from crushed sun ower achenes previously sprayed with the low Esfenvalerate and high applications , respectively.

3 For the purpose of developing Application strategies useful for avian Helianthus annuus repellents, we subsequently investigated blackbird feeding response to oilseed sun ower treated with Pyraclostrobin the anthraquinone - based repellent and either a registered insecticide or a registered fungicide popularly used for ripening sun ower. We observed a positive concentrationeresponse relationship among blackbirds exposed to anthraquinone and the insecticide ( esfenvalerate), or anthraquinone and the fungicide ( pyraclostrobin). Blackbirds reliably discriminated between untreated sun ower and that treated with 1810 ppm anthraquinone and of the insecticide or 1700 ppm anthraquinone and of the fungicide during our preference experiments. Given that ripening achenes are inverted from conventional pesticide applications throughout much of the period associated with blackbird depredation, we also evaluated blackbird repellency of the anthraquinone - based repellent applied to involucral bracts ( , the back of sun ower heads) of oilseed sun ower.

4 Blackbirds did not discriminate between untreated involucral bracts and those treated with foliar applications comparable to l/ha or l/ha; blackbirds consumed more achenes from untreated sun ower heads than from those treated with l/ha of the anthraquinone - based repellent . Supplemental repellent ef cacy studies should investigate blackbird response to anthraquinone - based repellents ( , l/ha) within 10e100 ha sun ower elds and include independent eld replicates with predicted bird damage, repellent appli- cation strategies developed for protection of ripening crops, pre- and at-harvest repellent residues, and bird damage and crop yield measurements. Published by Elsevier Ltd. 1. Introduction The feeding behavior of red-winged blackbirds (Agelaius phoe- niceus Linnaeus), common grackles (Quiscalus quiscula Linnaeus). and yellow-headed blackbirds (Xanthocephalus xanthocephalus * Corresponding author.)

5 Tel.: 1 970 266 6136; fax: 1 970 266 6138. Bonaparte) negatively impacts production of confectionery and E-mail address: ( Werner). oilseed sun ower (Helianthus annuus Linnaeus) each year in the 0261-2194/Published by Elsevier Ltd. 64 Werner et al. / Crop Protection 59 (2014) 63e70. United States of America (Linz and Hanzel, 1997; Linz et al., 2011; repellent on ripening oilseed sun ower, and blackbird feeding re- Werner et al., 2005, 2009, 2011). Blackbird damage to sun ower sponses to the anthraquinone - based repellent when (2) combined was estimated to be $ million annually in the prime sun ower with either a registered insecticide or a registered fungicide and (3). growing area of North America (Peer et al., 2003). The effectiveness applied to the back of sun ower heads ( , surface available for of lethal damage management is typically associated with localized foliar repellent applications on ripening crops).

6 The capture, care populations closed to immigration; thus, non-lethal alternatives and use of all birds associated with our studies were approved by are needed to manage damage caused by non-localized, or mobile the Animal Care and Use Committee of the United States Depart- blackbirds to sun ower crops (Linz et al., 2011). ment of Agriculture's (USDA) National Wildlife Research Center Chemical repellents provide a non-lethal alternative to man- (NWRC Study Protocols QA-1739, QA-1793; Werner- Study aging wildlife damages to agricultural production, including Director). blackbird depredation of sun ower crops (recently reviewed by Linz et al., 2011). anthraquinone was identi ed as a promising 2. Methods avian repellent in the early 1940's (Heckmanns and Meisenheimer, 1944). anthraquinone - based repellents have been used to effec- Field residue studies and laboratory ef cacy experiments are tively protect rice seed from blackbirds under captive and eld necessary for the development, registration, and commercializa- conditions (Avery et al.)

7 , 1997, 1998; Cummings et al., 2002a, 2002b; tion of experimental pesticides in the United States of America, Neff and Meanley, 1957), turf from Canada goose grazing in including blackbird repellents for sun ower crop protection captivity (Blackwell et al., 1999; Dolbeer et al., 1998), and whole- (Werner et al., 2009, 2011). We conducted a eld residue study to kernel corn and ripening corn from captive sandhill cranes and evaluate an anthraquinone - based repellent (Arkion Life Sciences). blackbirds, respectively (Blackwell et al., 2001; Carlson et al., 2013). as a red-winged blackbird repellent within a ripening oilseed anthraquinone is a naturally-occurring, cathartic purgative; its sun ower eld. We conducted ve subsequent laboratory ef cacy action is principally on the large intestine, and it is not effective if experiments to evaluate blackbird feeding responses to experi- transit through the small intestine is delayed (Fraser and Bergeron, mental applications of the anthraquinone - based repellent on 1991).

8 No anthraquinone - based repellents are registered currently oilseed sun ower. for agricultural applications in the United States of America. We previously conducted laboratory ef cacy experiments to Field residue study in ripening oilseed sun ower estimate the threshold concentration of an anthraquinone - based repellent (active ingredient 50% 9,10- anthraquinone ; Arkion Life We established 24 enclosures, or netted plots (each m Sciences, New Castle, DE, USA) for red-winged blackbirds long m wide m tall; mesh, polypropylene (1475 ppm anthraquinone ; Werner et al., 2009) and common netting) within the maturing oilseed sun ower eld on near Steele, grackles (9200 ppm anthraquinone ; Werner et al., 2011). We con- North Dakota on July 20e21, 2010. All nets were suspended with ducted laboratory residue testing with confectionery sun ower plots constructed of 5-cm diameter, galvanized poles.

9 The bottom heads treated with applications of the anthraquinone - based re- of all nets was secured within the eld using 45-cm rebar stakes pellent comparable to l/ha, l/ha and l/ha; we observed driven vertically through wooden boards (extended hori- 3489 ppm, 6001 ppm and 16,638 ppm anthraquinone among zontally to complete enclosures). A zipper was installed in one end sun ower seeds ( , achenes) sampled from these treated sun- of each enclosure to enable daily care of test subjects throughout ower heads, respectively (Werner et al., 2011). based upon these the eld residue study. laboratory results, we predicted that our CO2 backpack Application For ripening sun ower, >75% of annual blackbird damage oc- of l/ha to all sun ower heads in treated enclosures ( , curs within the rst 18 days after anthesis ( , owering period;. experimental Application strategy with expected maximized resi- Cummings et al.))

10 , 1989). The end of anthesis for sun ower is marked dues) would effectively repel common grackles within a confec- by the emergence of the last anther, which coincides with the tionery sun ower eld (Werner et al., 2011). We observed 18% beginning of yellow ray ower drop (Siddiqui, 1975). We planned sun ower damage among anthraquinone -treated enclosures and our eld residue study with red-winged blackbirds based upon our 64% damage among untreated enclosures populated with common previous laboratory and eld ef cacy results (Werner et al., 2009, grackles (Werner et al., 2011). 2011). Thus, a backpack CO2 sprayer was used to apply 0 l/ha, Although laboratory and eld ef cacy studies have been con- l/ha, or l/ha of the anthraquinone - based repellent to the ducted for several chemical repellents on rice and confectionery achenes on all sun ower heads within treated eld enclosures sun ower (Avery et al.