Behavioral responses of red-winged blackbirds (Agelaius phoeniceus) to viewing a conspecific distressed by 4-Aminopyridine

4-Aminopyridine (4-AP) is the only pesticide that can be legally used in the US to reduce bird damage in ripening grain fields. Birds that consume grain baits treated with 4-AP (‘Avitrol’ FC-99®) exhibit erratic behavior and emit vocalizations that presumably scare away the rest of the flock. Yet the behavior of 4-A Pintoxicated birds has not been documented, and we do not know how other birds react when observing these intoxicated birds or what these observers learn from their experience. Hence, we examined the behavior of 15 4-A Pintoxicated red-winged blackbirds (Agelaius phoeniceus (L.)) and found that initial signs of intoxication occurred 12.5 min after consumption of the bait, with death following 16.3 min later. During this 16-min intoxication period, birds gradually lost muscular control, making their movements and vocalizations weaker until hardly perceptible. Other captive red-winged blackbirds (‘observers’) gave more alarm calls while witnessing a 4-A P-intoxicated bird in one room of their cage (treatment period) than they did during the pre-treatment period. Immediately after the intoxicated bird died and was removed from the room, the observers' behaviour returned to pre-treatment levels. Broadcasting calls of an intoxicated bird or the placement of an untreated bird in one of the rooms had little effect on the observers' behavior. In another experiment, the placement of a 4-A Pintoxicated or untreated red-winged blackbird or the broadcast of calls of an intoxicated bird at a feed station did not affect the number of free-ranging conspecifics feeding, within sight of, or vocalizing at, these feeder stations. These results suggest that red-winged blackbirds learn little from witnessing a distressed conspecific.     

Improved multiple rapid immunofilter paper assay to detect three viruses of cucumber simultaneously

We improved a multiple rapid immunofilter paper assay (multi-RIPA) to simultaneously detect three major viruses of cucumber, Cucumber mosaic virus, Melon yellow spot virus and Zucchini yellow mosaic virus. When we increased the concentration of bovine serum albumin (BSA) in the extraction buffer, a positive band for each virus developed in the multi-RIPA, regardless of the order that the three sensitized white latex particles were immobilized on the strip. The increase in BSA concentration also strengthened the sensitivity of each RIPA. In addition, using a mixture of commercially available, red and blue, sensitized latex solutions as a tracer, purple bands could be produced on the strips. Because each virus yielded an unique color for a positive reaction, the three viruses were easy to distinguish.     

Contact action of diethylstilbestrol (DES)-impregnated paper strips on pregnant Levant voles: Effect of alteration of DES concentration and of total strip area

Placement of paper strips impregnated with a suspension of diethylstilbestrol (DES) in soybean oil into the cage of a pregnant Levant vole (Microtus guentheri [D. & A.]) causes disruption of pregnancy in almost all cases, provided the DES concentration is at least 0.062 mg/cm² and the total area of the strips is at least 100 cm². When the total strip area is 50 cm² or the DES concentration is 0.031 mg/cm², the activity of the strips is markedly reduced.     

Residue distribution of the acaricide coumaphos in honey following application of a new slow-release formulation

Acaricide used in beehives for the control of varroa often leaves residues in bee products. The behaviour and distribution of the acaricide coumaphos in honey following the application of a new slow-release strip formulation (CheckMite+) was assessed. The bee colonies were allowed to build new combs without foundation, and two strips were hung in the brood chamber of each colony for a period of 42 days. The distribution of coumaphos residues in honey in relation to the position of the frame and the duration of treatment was examined by collecting samples from each comb at various time intervals up to 145 days after treatment. In the brood chamber, coumaphos was incorporated into honey from the first day of application, and residues accumulated mainly in combs placed next to strips. In the adjacent combs, residues remained at low concentrations with slight variations. In the honey chamber, residue concentrations on the day of strip removal ranged between 0.006 and 0.020 mg kg(-1), while 79 days after application the concentration of coumaphos residues was below 0.020 mg kg(-1). Residues above the EC fixed maximum residue limit (MRL) of 0.1 mg kg(-1) were measured only in brood chamber honey obtained from those combs placed next to strips. In these samples, 0.060-0.111 mg kg(-1) of coumaphos was detected up to 103 days after strip removal. Coumaphos residues in honey extracted from combs that were placed at the edge of the brood chamber were found below the MRL value, even during the 42 day period of CheckMite+ strip treatment.     

Can field-scale habitat diversification enhance the biocontrol potential of spiders?

The study investigated the effect of strip management in alfalfa on the abundance and diversity of spiders. In strip management, narrow strips were left unmown in the crop, which were then shifted at next mowing. In an experimental field, out of the six 50 x 50-m blocks, three received strip management and three were managed traditionally (ie the whole block was mown). Our main hypothesis was that unmown strips will contain a more diverse and abundant spider assemblage, which will increase spider numbers in the mown parts of the crop. Over the 3 years of the study, unmown strips contained a spider assemblage of more than 50% higher abundance than in control alfalfa. Species diversity was also greater in the strips, and the presence of specific indicator species could be shown. We found that five dominant species comprised over 75% of spiders in the strips, and they were the same species as those that are dominant in alfalfa, where they represent 85% of all spiders. In contrast, a neighbouring meadow, which was a control in the study, also had high diversity, but different dominant species. The main result of the experiment was negative in that elevated abundance of spiders in unmown strips did not raise spider numbers in the mown strips of alfalfa, where abundance was only marginally higher than in the control alfalfa. We can speculate that better ecological conditions in unmown strips attract and conserve spiders from neighbouring areas and from the crop at mowing. We suggest that if diversification is more interspersed within the crop, we have a higher chance of increasing the number of natural enemies and bringing them closer to pests, so that they can interact more intensively.     

Consumption of fipronil-treated rice seed does not affect captive blackbirds

Fipronil is an insecticide developed for use on rice seed and other crops. In a series of cage and pen trials, we evaluated the responses to dyed, fipronil-treated rice seed of three bird species likely to encounter it in the field. Individually caged red-winged blackbirds (Agelaius phoeniceus), brown-headed cowbirds (Molothrus ater), and boat-tailed grackles (Quiscalus major) displayed no evidence of adverse reaction to treated seed. Chemical analyses of hulls from treated seeds eaten by captive birds revealed that 10–20% of the fipronil originally present was removed during feeding. In group enclosures, male red-winged blackbirds ate as much fipronil-treated rice as they did dyed, untreated seed. In four-day tests within a 0·2-ha flight pen, 10-bird blackbird flocks removed 11·4% of fipronil-treated seed from a test plot compared to 12·5% of dyed, untreated seed removed from the alternate plot. When the alternate plot contained undyed rice, however, seed removal from the treated plot averaged 2·4% compared to 28·9% from the alternative plot, suggesting that the groups of test birds avoided treated seed based on its appearance. We conclude that 325 and 500 mg kg^-1 fipronil applications alone do not affect avian feeding activity. © 1998 SCI.     

Aversion of the feral pigeon and the house sparrow to pellets and sprouts treated with commercial formulations of methyl anthranilate

Two methyl anthranilate formulations, ReJex‐iT® TP‐40 and AG‐36, were tested as bird‐repelling agents for animal feed and vegetable sprouts, respectively. Feral pigeons (Columba livia) and house sparrows (Passer domesticus) are important pests of animal husbandry and field crops in Israel. In each 4‐day experiment, four birds were held together in an aviary, and were offered four trays or dishes with animal feed or cauliflower sprouts in four corners of the cage. The trays and dishes were transposed daily in a Latin square sequence. Pigeons consumed significantly more untreated feed than treated feed. When no alternative untreated food was offered, there was no significant repellency. Treatment of animal feed with TP‐40 to give 2.0 ml methyl anthranilate kg^?1 or less had no repellent effect on sparrows. Concentrations of 4.0 ml kg^?1 or more repelled the sparrows significantly. When no untreated feed was presented, pigeons and sparrows preferred the lowest concentration of methyl anthranilate presented. When AG‐36 was tested on vegetable sprouts, the sparrows tended significantly to avoid the highest concentration used—14.5 ml methyl anthranilate litre^?1 spray. The inter‐specific differences between the birds indicate that the efficacy of methyl anthranilate formulations as a repellent has to be specified for every species. This study did not determine (1) the possibility of developing habituation, (2) the behaviour of birds under natural conditions in the field, or (3) the influence of the feeding behaviour of a sympatric bird species on the repellency of methyl anthranilate to other species. © 2001 Society of Chemical Industry     

Bait aggregation to reduce cost and toxin use in aerial 1080 baiting of small mammal pests in New Zealand

BACKGROUND: The metabolic toxin sodium fluoroacetate (‘compound 1080’) is widely used for controlling introduced mammalian pests in New Zealand. For large-scale operations, 1080 is distributed aerially in bait to kill brushtail possums (Trichosurus vulpecula Kerr) and ship rats (Rattus rattus L.). While usually successful in reducing pest populations by > 80%, widespread distribution of toxic bait is relatively expensive and raises concerns from some members of the public. Here, trials with spatial aggregation of baits in forested habitats were conducted to determine whether this can reduce toxin usage while maintaining operational efficacy. RESULTS: When 1080 baits were aggregated into clusters (by hand sowing) or into strips (by precision aerial deployment), indices of possum relative abundance were reduced by 92–100%, compared with 73–100% reductions using conventional aerial broadcasting, while all methods reduced relative abundance indices of rats by 88% or greater. Radio tracking indicated a kill rate of > 90% against possums, regardless of bait distribution method. CONCLUSIONS: Simply by modifying bait distribution patterns, spatial aggregation can be used to maintain the high encounter rate of pests with 1080 bait that is necessary for operational efficacy, while reducing current toxin usage by up to 80%. Aggregated bait delivery could have relevance for other mammalian pest control scenarios internationally. Copyright © 2012 Society of Chemical Industry     

Biological control of botrytis leaf blight of onion byGliocladium roseum applied as sprays and with fabric applicators

Gliocladium roseum (5×10⁶ conidia ml^–1) and chlorothalonil (Bravo 500) were compared in two field tests for effectiveness in suppressing leaf blight caused byBotrytis squamosa in cooking onions. The biological control agent and fungicide were applied with sprayers and with specially designed fabric applicators that were mounted interchangeably on an aluminium carriage with bicycle wheels. In the applicators, inoculum and fungicide gravitated from a reservoir down curtains of denim strips and onto portions of onion leaves contacted by the strips. Initial applications were timed using a leaf blight forecasting system (BOTCAST) and three or four subsequent applications were made at weekly intervals. When compared to water checks,G. roseum applied as sprays or by applicators reduced density of leaf spots by about 50–58% during middle and late stages of epidemics. The antagonist was about half as effective as chlorothalonil in suppressing density of spots, regardless of application method. The applicators delivered inoculum in similar densities to proximal and distal halves of leaves, and used at least 35% less volume of inoculum compared to the sprayers. Density of inoculum on leaves treated by applicators was about the same as in spray-treated leaves when canopies were sparse, but less when canopies were dense. It is concluded thatG. roseum has good potential for controlling leaf blight sufficiently to avoid economic yield losses.     

Evaluation of a pelleted bait containing methyl anthranilate as a bird repellent

No-till agriculture involves the use of granular pesticide formulations, chemically treated seeds, and pelleted baits. Some of these may accidentally kill birds. We have tested whether methyl anthranilate (MA), a known bird repellent, would eliminate consumption of a pelleted bait. In two laboratory experiments and an outdoor aviary trial, cowbirds (Molothrus ater Bodd.) were presented with pellets containing pesticide and MA, pellets containing pesticide but no MA, and carrier pellets without pesticide or MA. Consumption of any formulation was low, but the addition of MA significantly decreased bait loss in the laboratory, and prevented the disappearance of bait in the outdoor trial.     

The effects of seed mix and management on the abundance of desirable and pernicious unsown species in arable buffer strip communities

Buffer strips are refuges for a variety of plants providing resources, such as pollen, nectar and seeds, for higher trophic levels, including invertebrates, mammals and birds. Margins can also harbour plant species that are potentially injurious to the adjacent arable crop (undesirable species). Sowing perennial species in non‐cropped buffer strips can reduce weed incidence, but limits the abundance of annuals with the potential to support wider biodiversity (desirable species). We investigated the responses of unsown plant species present in buffer strips established with three different seed mixes managed annually with three contrasting management regimes (cutting, sward scarification and selective graminicide). Sward scarification had the strongest influence on the unsown desirable (e.g. Sonchus spp.) and unsown pernicious (e.g. Elytrigia repens) species, and was generally associated with higher cover values of these species. However, abundances of several desirable weed species, in particular Poa annua, were not promoted by scarification. The treatments of cutting and graminicide tended to have negative impacts on the unsown species, except for Cirsium vulgare, which increased with graminicide application. Differences in unsown species cover between seed mixes were minimal, although the grass‐only mix was more susceptible to establishment by C. vulgare and Galium aparine than the two grass and forb mixes. Annual scarification can enable desirable annuals and sown perennials to co‐exist, however, this practice can also promote pernicious species, and so is unlikely to be widely adopted as a management tool in its current form.     

Assessing the Hazard to Granivorous Birds Feeding on Chemically Treated Seeds

Current methods for evaluating hazards to seed-eating birds are based on estimated exposure per unit area and assume that birds ingest all of the chemical on a treated seed. In an earlier study, however, it was determined that red-winged blackbirds removed only about 15% of an insecticidal treatment applied to individual rice seeds. Here, we extend those findings by examining the seed-handling behavior of four granivorous bird species exposed to millet, rice, sunflower and sorghum treated with imidacloprid. Mourning doves (Zenaida macroura L.) swallowed the seed whole. House finches (Carpodacus mexicanus Müller), red-winged blackbirds (Agelaius phoeniceus L.) and boat-tailed grackles (Quiscalus major Vieillot) discarded the seed hulls, however, and removed only 15–40% of the initial chemical treatment. Residues on seed hulls decreased as handling time increased. Sunflowers had the lowest residues because birds repeatedly handled the hull to remove bits of the oily kernel. These results suggest that avian hazard assessment methods should incorporate species-typical seed-handling behavior to assess more accurately birds' exposure to chemicals on different types of seed. © of SCI.     

Potential for microbial diuron mineralisation in a small wine‐growing watershed: from treated plots to lotic receiver hydrosystem

BACKGROUND: Since biological degradation processes are known to be a major driver of the natural attenuation of pesticide residues in the environment, microbial communities adapted to pesticide biodegradation are likely to play a key environmental role in reducing pesticide exposure in contaminated ecosystems. The aim of this study was to assess the diuron‐mineralising potential of microbial communities at a small‐scale watershed level, including a diuron‐treated vineyard (pollution source), its associated grass buffer strip (as a river protection area against pesticide runoff) and the lotic receiver hydrosystem (sediments and epilithon), by using radiorespirometry. RESULTS: Comparison of results obtained at different sampling sites (in both soil and aquatic systems) revealed the importance of diuron exposure in the adaptation of microbial communities to rapid diuron mineralisation in the vineyard but also in the contaminated grass strip and in downstream epilithic biofilms and sediments. CONCLUSION: This study provides strong suggestive evidence for high diuron biodegradation potential throughout its course, from the pollution source to the final receiving hydrosystem, and suggests that, after microbial adaptation, grass strips may represent an effective environmental tool for mineralisation and attenuation of intercepted pesticides. Copyright © 2009 Society of Chemical Industry     

A survey of sheep dip usage in Scotland, 1973

A survey of sheep dipping and spraying in Scotland during 1973 has shown that about 40 tonnes of organophosphorus, 8 tonnes of organochlorine and 2 tonnes of carbamate insecticides were used to control ectoparasites. Substances used to combat headfly (Hydrotaea irritans) and the main areas of Scotland affected by this pest are noted. Information about the pattern of dipping in relation to geographical area, season and flock size and about the disposal of surplus dip and empty containers is presented. Though a small potential for environmental damage still exists no evidence of such came to light.     

Removal of duvatrienediols from the surface of tobacco leaves increases their susceptibility to blue mold

Dipping leaf strips of greenhouse or field-grown tobacco (Nicotiana tabacum L., cv. Ky-14) plants into acetone for 1 s, prior to inoculation with sporangia of Peronospora tabacina Adam, increased their susceptibility to blue mold. Disease severity and sporangial production on leaf discs from acetone-treated leaves were markedly increased compared to those on discs from untreated leaves. Treatment with acetone also decreased variation in susceptibility of leaves from plants of various ages. Disease severity on discs obtained from attached leaves which were dipped in acetone for 1 s was three times greater up to 15 days after dipping than on discs from leaves that were not dipped. TLC and GLC analyses of the acetone extracts indicated that 95% or more of the major cuticular diterpenoids, α- and β-4,8,13-duvatriene-1,3-diols (DVT), were removed from the surface by dipping for 1 s. These compounds had not reappeared on the leaf surface 15 days after leaves were dipped in acetone for 1 s. Aqueous suspensions of the acetone-soluble constituents as well as authentic DVT, inhibited sporangial germination of P. tabacina (ED₁₀₀ = 25 ppm) and the antifungal activity was accounted for by DVT. When DVT was removed from a leaf surface and added back to the same leaf strip, the resistance of the leaf tissue was restored. As tobacco plants aged, their susceptibility to blue mold decreased and the quantity of DVT on the leaf surface increased. The data support a role for DVT in the resistance of tobacco against blue mold.     

Impact of intercropping on epidemics of groundnut leaf spots: defining constraints and opportunities through a 7‐year field study

Plant diversity can have a profound impact on disease dynamics, with important applications for enhancing sustainability. Disease is often reduced by intercropping, but variability can be high. This study investigated integration of several management approaches to stabilize this variability for early leaf spot (ELS) and late leaf spot (LLS) of groundnut, over seven seasons in three phases. In phase 1, monocrops and alternating row and strip intercrops with maize were artificially inoculated with ELS in an area with little groundnut production. Reductions in AUDPC of 37–73% in strip treatments compared to monocrops prompted testing of the efficacy of intercropping in intensive production areas for phases 2 and 3. Additional treatments included cotton strip intercrops, and integration of intercropping with reduced fungicide treatments and partial resistance to leaf spots. In phase 2, the use of cotton strip intercrops lowered natural ELS epidemics by 25–41% (AUDPC) through delayed disease onset, but maize had inconsistent effects. Intercropping was not effective against LLS, which dominated in phase 3. Reduced fungicide regimes and partial resistance lowered disease, and in one case interacted with intercropping to enhance disease suppression. Groundnut yields generally were inversely proportional to disease levels and not significantly reduced by intercropping. Separate studies to determine maize impacts on ELS infection implicated disruption of dispersal as the mechanism of disease reduction. This work demonstrates that intercropping may be most effective where low levels of ELS are present, using strip patterns with cotton, and combined with other tools such as resistance and reduced fungicide application.     

Side effects of grain protectants on biological control agents: How <Emphasis Type="Italic">Hyptis</Emphasis> plant extracts affect parasitism and larval development of <Emphasis Type="Italic">Dinarmus basalis</Emphasis>

Dinarmus basalis Rondani (Hymenoptera: Pteromalidae), an ectoparasitoid of bruchid pests of stored cowpeas (Vigna unguiculata), is a potential biological control agent. We investigated whether grain protectants from Hyptis spicigera and H. suaveolens (Lamiaceae) disturb parasitism and post-embryonic growth of the parasitoid. When cowpeas containing bruchid larvae were treated before being placed in the presence of D. basalis females, the rate of parasitism decreased on average up to 24% and 47% in the presence of, respectively, leaf dry powder and essential oils from both plant species. The estimated larval mortality was higher on treated (9.55 to 28.6%) than on non-treated parasitized hosts (2.8%), depending on the plant species and the plant extract tested. Additional larval mortality was higher for essential oil, and for H. suaveolens. An in-depth analysis of the pre-imaginal development in capsules adapted for this purpose showed that without treatment, mortality was recorded only for eggs and the first two larval stages. With treatment, mortality not only significantly increased on eggs but also spanned all other pre-imaginal stages. Pre-imaginal development was also significantly extended in the presence of treatment, depending on the type of extract and dose used. In conclusion, both plant species exert acute toxicity on D. basalis larvae and also act as growth inhibitors. These results provide additional information that enable us to move towards the harmonious use of allelochemical compounds from plants while protecting biocontrol agents from their adverse effects.     

Potential of Heterorhabditis zealandica (Rhabditida: Heterorhabditidae) for the control of codling moth,Cydia pomonella (Lepidoptera: Tortricidae) in semi-field trials under South African conditions

Infection of codling moth, Cydia pomonella (L.), larvae by the entomopathogenic nematode, Heterorhabditis zealandica, was studied under semi-field conditions. Late-instar diapausing codling moth larvae, coccooned in perforated cardboard strips, were used in all trials to evaluate the nematode treatments involved. A morning application of 0.5, 1.0 and 1.5 MM infective juveniles (IJs) per tree resulted in 85%, 95% and 100% codling moth larval infection, respectively. Contrasting results were obtained for an evening application, with low levels of codling moth infection (<50%). Nematode treatment strips placed in direct sunlight resulted in almost no infection (<10%), opposed to strips attaining 67% infection placed in the shade.     

A mixed indicator strip for phosphine detection

A rapid, sensitive and reliable mixed indicator paper strip impregnated with dimethyl yellow (0.05%), cresol red (0.1%) and mercuric chloride (1.0%) in methanol has been developed for the detection of phosphine (PH₃) in air at the permissible level (TLV). The paper strip turns red in the presence of phosphine. It is highly sensitive and has better shelf-life than indicator strips impregnated with dimethyl yellow plus mercuric chloride or cresol red plus mercuric chloride.     

Direct and indirect efficacy of truck-mounted applications of s-methoprene against Aedes albopictus (Diptera: Culicidae)

Aedes albopictus (Skuse) is a globally significant vector that complexifies management programs already contending with Aedes aegypti (L.). The Ae. albopictus mosquito is a daytime biting, container breeding, anthropophilic mosquito that is generally considered unresponsive to operational larviciding that does not also incorporate source reduction. S-methoprene is a readily available juvenile hormone mimic common to pest management. This 14-week study examines direct and indirect treatment efficacy using s-methoprene as an ultra-low volume (ULV) truck spray in area-wide operations against Ae. albopictus in the southeastern United States. An overall 63.3% reduction of Ae. albopictus adults and 47.8% reduction of deposited eggs in treatment areas were observed compared with control. Indirect plots saw reduction in Ae. albopictus adults by 32.7% and eggs by 32.3%. Using insect growth regulator bioassays, truck-mounted ULV application of s-methoprene was effective to an inhibition of emergence (IE) of ≥92% within directly treated (sprayed) areas and >65% IE among containers placed up to 90 m away. S-methoprene could still benefit urban vector management programs when applied at an operational scale.