Pan trapping is an effective method to trap adults of the jujube gall midge, Dasineura jujubifolia (Diptera: Cecidomyiidae)

Jujube gall midge (Dasineura jujubifolia Jiao & Bu) (Diptera: Cecidomyiidae) is an important pest in jujube (Ziziphus jujuba Mill.) orchards in Aksu, Xinjiang, China. Yellow sticky traps are the main device used for monitoring jujube gall midge adults, but their efficacy is low. Here, we compared the effectiveness of yellow sticky traps with water pan traps (are commonly used for trapping Diptera insects) to monitor jujube gall midge adults. Yellow sticky traps and pan traps were deployed for 2 consecutive years in jujube orchards in Aksu, Xinjiang, China. The midge's population dynamics as revealed by these 2 trap types were consistent, but the effectiveness of pan traps was about 5 times greater than that of the yellow sticky traps. In addition, pan traps captured fewer non-target species (e.g., parasitic wasps, lacewings, and lady beetles) than yellow sticky traps. Our study suggests that pan trap is an effective device to monitor jujube gall midge adults with minimal harm to natural enemies.

Behavioral Responses of Western Flower Thrips (Frankliniella occidentalis) to Visual and Olfactory Cues at Short Distances

Western flower thrips (WFT), Frankliniella occidentalis (Pergande), is a highly invasive pest, infesting many species of plants worldwide, but few studies have investigated the visual and olfactory cues associated with their foraging behaviors. In this study, the distance traveled by WFT to locate yellow cards using only visual cues and visual cues plus olfactory cues was studied first. Subsequently, preferences for colors (white, red, green, purple, yellow and blue) and patterns (triangle, rectangle, circle and flower-shape) over short distances were assessed with free-choice tests. Finally, as yellow was the most efficient color to catch WFT under laboratory conditions, the yellow flower-shape was used as the visual cue, and preferences between visual and olfactory cues were evaluated with dual choice tests. The results showed that the capture rate of WFT by visual cues decreased as selection distance increased, however capture rate remained higher with the addition of olfactory cues. The flower shape attracted the greatest number of WFT among all shapes tested. The combination of visual cues and extracted volatiles from flowering Medicago sativa L. attracted higher numbers of WFT than to the olfactory cues alone, however these were similar to visual cues alone. The presence of olfactory cues resulted in higher residence times by WFT than did the absence of olfactory cues. These results show the relative effects of visual and olfactory cues on the orientation of WFT to hosts and highlight that visual cues dominate selection behavior at short distances. These findings can be used in the development of efficient trapping products and management strategies for thrips.

Sugar-Acetic Acid-Ethanol-Water Mixture as a Potent Attractant for Trapping the Oriental Fruit Moth (Lepidoptera: Tortricidae) in Peach-Apple Mixed-Planting Orchards

Sugar–acetic acid–ethanol–water mixture (SAEWM) trapping has initially shown the potential efficacy for monitoring or trapping insects. It is unknown how SAEWM-baited traps affect field number of oriental fruit moth (OFM), Grapholita molesta (Busck) (Lepidoptera: Tortricidae), the female/male ratio trapped, and the type of natural-enemy insects captured. This study investigated changes in seasonal population dynamics and diurnal flight rhythm of OFM, the number and female/male ratio of OFM and the numbers of Coccinellidae and Chrysopidae trapped by SAEWM in peach–apple mixed-planting orchards. The SAEWM performed well in trapping OFM, most of which were adult females, with the maximum trapping at 2.5 m above ground. The daily trapping peak occurred between 18:00 and 20:00, during each continuous monitoring period, with another peak occurring at 4:00–8:00, after the second monitoring period (2–5 July). However, the use of SAEWM also resulted in the trapping of Coccinellidae and Chrysopidae, of which peak trapping time partially overlapped with the second and third peak trapping times of OFM. We suggest the cessation of SAEWM trapping during the peak activity time of Coccinellidae and Chrysopidae, or application of alternative attractive mixture that do not trap the natural enemy insects, in order to protect the ecological balance in the field.

Natural and synthetic vocalizations of brown rat pups, Rattus norvegicus, enhance attractiveness of bait boxes in laboratory and field experiments

BACKGROUND

Rats are often neophobic and thus do not readily enter trap boxes which are mandated in rodent management to help reduce the risk of accidental poisoning or capture of non-target animals. Working with brown rats, Rattus norvegicus, as a model species, our overall objective was to test whether sound cues from pups could be developed as a means to enhance captures of rats in trap boxes.

RESULTS

Recording vocalizations from three-day-old pups after removal from their natal nest with both sonic and ultrasonic microphones revealed frequency components in the sonic range (1.8-7.5 kHz) and ultrasonic range (18-24 kHz, 33-55 kHz, 60-96 kHz). In two-choice laboratory bioassays, playback recordings of these vocalizations induced significant phonotactic and arrestment responses by juvenile, subadult and adult female and male rats. The effectiveness of engineered 'synthetic' rat pup sounds was dependent upon their frequency components, sound durations and the sound delivery system. Unlike other speakers, a piezoelectric transducer emitting sound bursts of 21 kHz with a 63-KHz harmonic, and persisting for 20-300 ms, proved highly effective in attracting and arresting adult female rats. In a field experiment, a battery-powered electronic device fitted with a piezoelectric transducer and driven by an algorithm that randomly generated sound cues resembling those recorded from rat pups and varying in fundamental frequency (19-23 kHz), duration (20-300 ms) and intermittent silence (300-5000 ms) significantly enhanced captures of rats in trap boxes baited with a food lure and soiled bedding material of adult female rats.

CONCLUSION

Our study provides proof of concept that rat-specific sound cues or signals can be effectively reproduced and deployed as a means to enhance capture of wild rats. © 2016 Society of Chemical Industry.