Effectiveness of AV-1011 to Reduce Damage to Drill-Planted Rice From Blackbirds

We determined efficacy of AV-1011 (a 50% anthraquinone product; Arkion Life Sciences, New Castle, Delaware) on drill-planted rice seed to reduce blackbird damage and determine residue levels of anthraquinone (AQ) in rice seeds and seedlings and in the mature rice crop under field enclosures at the University of Missouri-Delta Center farm near Portageville, Missouri. Red-winged blackbird (Agelaius phoeniceus) damage was higher for untreated than AV-1011 treated rice seedlings at assessment period 3, 15 days postplanting (F1,141 1⁄4 15.81, P < 0.001), and at assessment period 4, 19 days postplanting (F1,136 1⁄4 11.54, P 1⁄4 0.001). Blackbird damage to AV-1011-treated seedling for assessment periods 3 and 4 was 8% and 7%, respectively, while blackbird damage to untreated seedlings during the same assessment periods was 52% and 44%. More blackbirds used untreated plots than AV-1011-treated plots during assessment periods 2–4 (F1,17.8 1⁄4 20.02, P < 0.001). Overall concentrations of AQ on seeds averaged 5,993 mg/g or 0.59% during the test period. Concentrations of AQ in mature rice seed and plant collected at harvest averaged 1.22 mg/g and 0.10 mg/g, respectively. AV-1011 offers promise for reducing bird depredations to newly planted rice, but additional testing should be conducted to evaluate this repellent in a large-scale field setting. 2011 The Wildlife Society.