Review of anthraquinone applications for pest management and agricultural crop protection

We have reviewed published anthraquinone applications for international pest management and agricultural crop protection from 1943 to 2016. Anthraquinone (AQ) is commonly found in dyes, pigments and many plants and organisms. Avian repellent research with AQ began in the 1940s. In the context of pest management, AQ is currently used as a chemical repellent, perch deterrent, insecticide and feeding deterrent in many wild birds, and in some mammals, insects and fishes. Criteria for evaluation of effective chemical repellents include efficacy, potential for wildlife hazards, phytotoxicity and environmental persistence. As a biopesticide, AQ often meets these criteria of efficacy for the non-lethal management of agricultural depredation caused by wildlife. We summarize published applications of AQ for the protection of newly planted and maturing crops from pest birds. Conventional applications of AQ-based repellents include preplant seed treatments [e.g. corn (Zea mays L.), rice (Oryza sativa L.), sunflower (Helianthus annuus L.), wheat (Triticum spp.), millet (Panicum spp.), sorghum (Sorghumbicolor L.), pelletized feed and forest tree species] and foliar applications for rice, sunflower, lettuce (Lactuca sativa L.), turf, sugar beets (Beta vulgaris L.), soybean (Glycine max L.), sweet corn and nursery, fruit and nut crops. In addition to agricultural repellent applications, AQ has also been used to treat toxicants for the protection of non-target birds. Few studies have demonstrated AQ repellency in mammals, including wild boar (Sus scrofa, L.), thirteen-lined ground squirrels (Ictidomys tridecemlineatus,Mitchill), black-tailed prairie dogs (Cyomys ludovicainus, Ord.), common voles (Microtus arvalis, Pallas), housemice (Musmusculus, L.), Tristram’s jirds (Meriones tristrami, Thomas) and black rats (Rattus rattus L.). Natural sources of AQ and its derivatives have also been identified as insecticides and insect repellents. As a natural or synthetic biopesticide, AQ is a promising candidate for many contexts of non-lethal and insecticidal pest management

Influence of extender, freezing rate, and thawing rate on post-thaw motility, viability and morphology of coyote (Canis latrans) spermatozoa

Abstract The objective of this study was to examine the post-thaw effects of three cryoprotective extenders (Tris-fructose-citric acid extender, Tris-glucose-citric acid extender, and lactose extender), three linear freezing rates (À1, À6, and À20 8C/min), and three thawing rates (37 8C water bath for 120 s, 60 8C water bath for 30 s, and 70 8C water bath for 8 s) on coyote spermatozoa. After thawing, the findings supported that cryopreservation of coyote (Canis latrans) spermatozoa frozen at a moderate freezing rate (À6 8C/min), in either a Tris-fructose or Tris-glucose extender, and thawed at a slow rate (37 8C water bath for 120 s) or moderate rate (60 8C water bath for 30 s), resulted in a more vigorous post-thaw motility (range, 57.5-44.0%) and viability (range, 64-49.6%) with the least amount of morphological and acrosomal abnormalities.

Assessment of cabergoline as a reproductive inhibitor in coyotes (\u3ci\u3eCanis latrans\u3c/i\u3e)

The efficacy of three oral formulations (gelatin capsule, tablet, oil base) and five dosages (50, 100, 250, 500, 1000 μg) of cabergoline to disrupt reproduction in coyotes (Canis latrans) was evaluated. The type of formulation used had no effect on plasma progesterone and prolactin concentrations or on mean litter size. No adverse side effects (for example, vomiting, anorexia, diarrhea) were observed despite the use of doses of up to 20 times the therapeutic dose used for domestic dogs and cats. All coyotes treated with 50, 100, 250 and 500 μg cabergoline whelped, but plasma progesterone concentrations in these coyotes were lower (P ≤ 0.07) than in control animals at day 7 after treatment. Ten of 11 females treated with 1000 yg cabergoline whelped, but progesterone concentrations in these coyotes were lower than in control animals up to day 14 after treatment ( P ≤ 0.04). Dosages of 1 000 μg cabergoline decreased blood serum prolactin (P ≤ 0.1 0) and progesterone (P ≤ 0.06) concentrations, but apparently failed to decrease progesterone below the threshold necessary to maintain pregnancy in all but one animal. However, progressive inhibition of prolactin and progesterone with increasing doses of cabergoline indicated that higher dosages might be effective in coyotes. Survival of pups born to cabergoline-treated females was not different (P \u3c 0.001) from that of pups born to control females, but mean litter size was smaller for females treated with cabergoline (P ≤ 0.073) than for the control females. Although all cabergoline treatments in this study were ineffective at preventing reproduction in coyotes, progressive inhibition of prolactin and progesterone with increasing dosages of cabergoline indicates that higher doses might be effective in preventing reproduction in coyotes. However, the physiological differences from other canine species in dopamine D2 receptors and mechanisms of luteal support may ultimately prevent the use of cabergoline for reproductive control in coyotes

Efficacy of repellent-treated structural barriers for Richardson’s ground squirrels (\u3ci\u3eUrocitellus richardsonii\u3c/i\u3e (Sabine)) and house mice (\u3ci\u3eMus musculus\u3c/i\u3e L.)

The worldwide presence of vertebrate pests such as rodents has created a need for non-lethal control methods that can be applied to integrated pest management plans. Chemical repellents are often a useful wildlife management tool as they can be directly applied to a commodity or structure to prevent infringement and damage. We assessed the efficacy of an anthraquinone (AQ)-based repellent in a structural barrier model against Richardson’s ground squirrels (Urocitellus richardsonii (Sabine)) (RGS) and house mice (Mus musculus L.). The AQbased repellent was applied to pieces of burlap which were secured over each end of a small section of PVC pipe. Unadulterated enrichment food was then offered within the enclosed PVC pipe to motivate interactions with repellent-treated and untreated burlap barriers. Defeat of the barrier was defined as a physical breach by means of chewing the burlap or burlap/repellent barrier such that the test animal was able to gain entry to the hide and the enrichment food. RGS defeated 55% (±7.9) of untreated barriers, 25% (±6.8) of barriers treated with 50% dilution AQ-based repellent, and 27.5% (±5.6) of barriers treated with 0% dilution AQ-based repellent. House mice defeated 100% (±0.0) of untreated barriers, 20.5% (±6.4) of barriers treated with 50% dilution AQbased repellent, and 45.5% (±7.8) of barriers treated with 0% dilution AQ-based repellent. Relative to untreated barriers, AQ treatments reduced defeat of the barrier by 50–55% for RGS and 55–80% for house mice. RGS showed a marked decrease in consumption of enrichment food after exposure to AQ. The 0% dilution of AQtreated structural barrier had more individuals of both RGS and house mice chew through the structural barrier than the 50% dilution despite the increased concentration of AQ. We hypothesized that the additional water in the 50% dilution may have allowed for greater absorption of the repellent throughout the burlap fibers, thus enabling greater interaction with the AQ-treated barriers. Our results indicate that AQ-based repellents show promise as structural barriers for RGS and house mice

Concentration-response of an anthraquinone-based repellent for raccoons (\u3ci\u3eProcyon lotor\u3c/i\u3e)

Wildlife repellents can be part of non-lethal management strategies to reduce the negative impacts of wildlife to property, agricultural production, and human health and safety. Raccoons (Procyon lotor) are associated with negative impacts in all three of these areas. Anthraquinone is a useful avian repellent and its utility as a mammalian repellent is still being explored. Our objective was to evaluate laboratory efficacy of an anthraquinone-based repellent for raccoons using different concentrations. We fed captive raccoons whole corn treated at 0.5%, 1%, 1.5% and 2% anthraquinone and examined their behavioral response related to feeding repellency including consumption and change in duration related to approach, interaction and extended interaction with the feed bowl. Feeding repellency was 26–37% for whole corn treated with 0.5–1.5% anthraquinone and 71% for whole corn treated with 2% anthraquinone. Interaction duration among the treatments varied (p = 0.005) with a longer interaction duration with the food bowl at 2% anthraquinone compared to 0.5% anthraquinone. However, the addition of anthraquinone did not significantly alter behaviors of approach, interaction, or extended interaction between pretreatment and treatment for the raccoons within treatments. The decreases in consumption that we observed warrant development of further research and field evaluation regarding anthraquinone as a deterrent with raccoons or to repel vertebrate competitors from raccoon specific baits

Repellent application strategy for wild rodents and cottontail rabbits

Effective chemical repellents and repellent application strategies are needed to manage damages caused by wild rodents and rabbits to agricultural resources. For the purpose of comparatively investigating the behavioral response of wild rodents and rabbits to a chemical repellent, we experimentally evaluated the concentration-response relationship of an anthraquinone-based repellent in California voles (Microtus californicus Peale), Richardson’s ground squirrels (Urocitellus richardsonii Sabine), deer mice (Peromyscus maniculatus Wagner) and cottontail rabbits (Sylvilagus audubonii Baird) in captivity. We observed 52–56% feeding repellency for whole oats treated with 10,800ppm anthraquinone or 18,500ppmanthraquinone in mice and squirrels, and 84–85% repellency for oats treated with 18,300ppm anthraquinone or 19,600ppm anthraquinone in voles and rabbits, respectively. In addition to providing the negative postingestive consequences necessary for conditioned food avoidance, the anthraquinonebased repellent also absorbs ultraviolet (UV) wavelengths that are visible to most wild birds. For the purpose of developing a repellent application strategy to modify the behavior of vertebrate pests, we therefore conducted a conditioned avoidance experiment by offering repellent- and UV-treated food to California voles in a subsequent behavioral assay. Relative to unconditioned test subjects (P = 0.3161), voles conditioned with the UV, postingestive repellent subsequently avoided whole oats treated only with an UV cue (P = 0.0109). These behavioral responses to anthraquinone-based repellents and UV feeding cues can be exploited as a repellent application strategy for wild mammals. We discuss potential applications of preplant seed treatments and surface treatments that include postingestive repellents and related visual cues for the protection of agricultural resources associated with mammalian depredation

Repellent application strategy for wild rodents and cottontail rabbits

Effective chemical repellents and repellent application strategies are needed to manage damages caused by wild rodents and rabbits to agricultural resources. For the purpose of comparatively investigating the behavioral response of wild rodents and rabbits to a chemical repellent, we experimentally evaluated the concentration-response relationship of an anthraquinone-based repellent in California voles (Microtus californicus Peale), Richardson’s ground squirrels (Urocitellus richardsonii Sabine), deer mice (Peromyscus maniculatus Wagner) and cottontail rabbits (Sylvilagus audubonii Baird) in captivity. We observed 52–56% feeding repellency for whole oats treated with 10,800ppm anthraquinone or 18,500ppmanthraquinone in mice and squirrels, and 84–85% repellency for oats treated with 18,300ppm anthraquinone or 19,600ppm anthraquinone in voles and rabbits, respectively. In addition to providing the negative postingestive consequences necessary for conditioned food avoidance, the anthraquinonebased repellent also absorbs ultraviolet (UV) wavelengths that are visible to most wild birds. For the purpose of developing a repellent application strategy to modify the behavior of vertebrate pests, we therefore conducted a conditioned avoidance experiment by offering repellent- and UV-treated food to California voles in a subsequent behavioral assay. Relative to unconditioned test subjects (P = 0.3161), voles conditioned with the UV, postingestive repellent subsequently avoided whole oats treated only with an UV cue (P = 0.0109). These behavioral responses to anthraquinone-based repellents and UV feeding cues can be exploited as a repellent application strategy for wild mammals. We discuss potential applications of preplant seed treatments and surface treatments that include postingestive repellents and related visual cues for the protection of agricultural resources associated with mammalian depredation

Applications of Sensory Ecology for Wildlife Damage Management

Human-wildlife conflicts typically involve fundamental processes associated with the feeding behavior and/or the spatial behavior of wildlife. Thus, most human-wildlife conflicts arise from wildlife consuming products and/or wildlife occupying places valued by humans. For mammals, taste is the most important sensory cue for selecting nutrients and avoiding toxins. Most birds use both flavor (i.e. taste, odor, texture) and visual cues for their food selection process. We previously learned that an ultraviolet visual cue can enhance the repellency of an anthraquinone-based repellent for blackbirds, starlings, Canada geese and wild turkeys. Although the ultraviolet cue is not itself aversive, novel repellent formulations including ultraviolet cues have provided repellent efficacy at reduced concentrations of the repellent active ingredient. Ultraviolet repellent formulations are currently being developed for the protection of ripening agricultural crops from bird depredation. With regard to spatial behavior, exteroceptive sensory cues (e.g. visual, auditory, tactile cues) are reliably used for patch selection. We suggest that sensory cues and their paired consequences can be exploited for the development and application of effective strategies for wildlife damage management

Repellent Surface Applications for Pest Birds

Common pest birds in the United States include the non-native European starling (Sturnus vulgaris), house sparrow (Passer domesticus), and the pigeon (Columba livia domestica), as well as native birds including Canada geese (Branta canadensis) and gull species (Laridae). Large concentrations of pest birds can create human health hazards and monetary losses due to consumption of crops, depredation, and fecal contamination and accumulation. Fecal contamination hazards include the potential spread of zoonotic diseases including antimicrobial-resistant zoonoses and human injury due to the accumulation of fecal material on walking surfaces. Additionally, fecal accumulation causes structural and aesthetic damage due to the accelerated deterioration of building materials and increased maintenance costs. Methods to alleviate hazards and damages from aggregations of pest birds are needed. In a series of 3 experiments conducted in Fort Collins, Colorado, USA, between 2016 and 2018, we evaluated 3 surface-application repellent formulations for the reduction of fecal accumulations due to European starlings: Airepel® HC with castor oil, an anthraquinone-based repellent; Airepel HC with castor oil without anthraquinone; and MS2, a novel inert formulation with a tacky, oily texture. We compared each formulation directly to an untreated control. All 3 formulations reduced fecal accumulations beneath treated aluminum perches as compared to fecal accumulations beneath untreated aluminum perches. Interestingly, both formulations that contained no anthraquinone worked equally well or better than Airepel HC with castor oil, the anthraquinone-based formulation. The benefits of an exclusively inert formulation include less risk to applicators and non-target species. Comprehensive experimental field testing of these surface-application repellent formulations is warranted

Vision in an abundant North American bird: The Red-winged Blackbird

Avian vision is fundamentally different from human vision; however, even within birds there are substantial between species differences in visual perception in terms of visual acuity, visual coverage, and color vision. However, there are not many species that have all these visual traits described, which can constrain our ability to study the evolution of visual systems in birds. To start addressing this gap, we characterized multiple traits of the visual system (visual coverage, visual acuity, centers of acute vision, and color vision) of the Red-winged Blackbird (Agelaius phoeniceus), one of the most abundant and studied birds in North America. We found that Red-winged Blackbirds have: wide visual coverage; one center of acute vision per eye (fovea) projecting fronto-laterally with high density of single and double cones, making it the center of both chromatic and achromatic vision; a wide binocular field that does not have the input of the centers of acute vision; and an ultraviolet sensitive visual system. With this information, we parameterized a Red-winged Blackbird-specific perceptual model considering different plumage patches. We found that the male red epaulet was chromatically conspicuous but with minimal achromatic signal, but the male yellow patch had a lower chromatic but a higher achromatic signal, which may be explained by the pigment composition of the feathers. However, the female epaulet was not visually conspicuous in both the chromatic and achromatic dimensions compared with other female feather patches. We discuss the implications of this visual system configuration relative to the foraging, antipredator, mate choice, and social behaviors of Red-winged Blackbirds. Our findings can be used for comparative studies as well as for making more species-specific predictions about different visual behaviors for future empirical testing