Effect of trap size, placement, and age on captures of blueberry maggot flies (Diptera: Tephritidae)

Ammonium acetate and protein hydrolysate baited and unbaited green spheres (3.6, 9.0, and 15.6 cm diameter) were evaluated for effectiveness in capturing blueberry maggot flies, Rhagoletis mendax Curran. Early in the season, baited spheres (9.0 cm diameter) captured significantly more R. mendax flies than spheres of 3.6 and 15.6 cm diameter. As the season progressed, the differences in trap captures became less pronounced among the 3.6-, 9.0-, and 15.6-cm-diameter spheres. In other experiments, the effects of trap positions and age on captures of blueberry maggot flies were assessed. Traps were positioned 15 cm above the bush canopy, 15 cm inside the canopy (from top of the bush), and 45 cm from the ground. Traps placed within the canopy captured 2.5 and 1.5 times as many flies compared with traps placed above the canopy and 45 cm from the ground, respectively. When sticky yellow Pherocon AM boards and green sphere traps were allowed to age in field cages, freshly baited (0 d) yellow sticky boards captured significantly more blueberry maggot flies than boards aged for 11, 28, and 40 d, respectively. No significant differences were observed among boards aged for 11, 28, and 40 d. However, when baited 9-cm sticky spheres were aged in field cages, there were no significant differences between freshly baited spheres and spheres aged for 11 and 28 d, respectively. Spheres aged for 40 d differed significantly from freshly baited ones. The study demonstrated that the baited 9-cm-diameter sphere was more effective in capturing blueberry maggot flies than spheres of 3.6 and 15.6 cm diameter. When this trap is deployed in the center of the bush canopy approximately 15 cm from the top of the bush, it is attractive and accessible to R. mendax flies. The data also indicated that a baited 9-cm sphere has a longer effective life span than Pherocon AM boards when deployed under the same field conditions.     

Monitoring oak processionary moth Thaumetopoea processionea L. using pheromone traps: the influence of pheromone lure source,trap design and height above the ground on capture rates

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Factors affecting captures of male citrus leafminer, Phyllocnistis citrella Stainton, in pheromone-baited traps

The citrus leafminer, Phyllocnistis citrella Stainton (Lepidoptera: Gracillariidae), is an important world‐wide pest of citrus. Larval mining within leaf flush impacts yield and predisposes trees to infection by citrus canker, Xanthomonas axonopodis pv. citri. The present series of studies sought to identify factors affecting male P. citrella catch in pheromone‐baited traps with the intent of developing effective monitoring. A commercially available pheromone lure (Citralure, ISCA Technologies, Riverside, CA, USA) was highly effective in attracting male P. citrella to traps. Pherocon VI Delta (Trécé Inc., Adair, OK, USA) traps baited with a Citralure captured more male P. citrella than identically baited Pherocon IC Wing traps (Trécé Inc.). The superiority of the Delta‐style trap was found to be due to a 3 cm long closing latch that likely prevents males from flying directly through the trap without capture. Within canopies of mature citrus trees (approximately 3.5 m high), traps at mid‐canopy height (2.0 m) captured more males than traps placed higher (3.5 m) or lower (0.6 m). On the canopy perimeter and in between canopies, traps near ground level (0.6 m height) captured more males than traps at 2.0 and 3.5 m heights. Male catch was greater within the tree canopy or on the canopy perimeter than 2.0 away from the canopy. Traps deployed in trees on the edge of groves captured more males than traps placed 120 and 240 m away from the grove edge and within the grove interior. In non‐pheromone‐treated grove plots, the optimal dosage for catching males was between 0.1 and 1.0 mg of the 3 : 1 blend of (Z,Z,E)‐7,11,13‐hexadecatrienal and (Z,Z)‐7,11‐hexadecadienal; however, in pheromone‐treated plots a higher 10.0 mg dosage lure was most effective. Male catch in pheromone‐baited traps exhibited a diel rhythm with most males captured during scotophase (22:00–23:00 h) and no males captured during photophase.     

Infection of wild and cultivated Vaccinium spp. with blueberry leaf mottle nepovirus

A field survey was performed during the summers of 1991 and 1992 to determine whether blueberry leaf mottle virus (BLMV) infects wild blueberry bushes surrounding commercial blueberry fields and might act as a reservoir of the virus. Leaf samples from wild blueberries growing in wooded areas surrounding commercial plantings in Western central Lower Michigan were taken from bushes radiating out from the border of the commercial field into the wooded areas at 5, 50 and 100 m. BLMV was present in native bushes of Vaccinium corymbosum, V. myrtilloides and V. angustifolium, and two hybrids of V. corymbosum V. angustifolium. BLMV-infected pollen grains were detected in pollen traps located up to 2 miles from a source field.     

The influence of tree species and edge effects on pheromone trap catches of oak processionary moth Thaumetopoea processionea (L.) in the U.K.

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Horizontal and vertical distribution of flower thrips in southern highbush and rabbiteye blueberry plantings, with notes on a new sampling method for thrips inside blueberry flowers

The dispersal behavior of flower thrips was studied during two field seasons within blueberry (Vaccinium spp.) plantings in Florida and southern Georgia. A "shake and rinse" technique used to extract thrips from inside the blueberry flowers was not significantly different from the conventional dissecting technique, but the time taken to complete the extraction of thrips was significantly shorter. Overall, the highest concentration of thrips was captured inside the canopy of blueberry bushes. Using a grid of traps to monitor the dispersal of thrips during the blueberry flowering season, we analyzed their dispersion with graphical and analytical methods to determine and describe their distribution within blueberry plantings. Thrips began to form "hot-spots" 5-7 d after bloom initiation. A hot-spot is defined as a large number of thrips concentrated in a small area of the field, whereas the rest of the field has a low population. The behavior of the population inside these hot-spots fit a Gaussian tendency and a regression was conducted to describe this tendency. Green's and Standardized Morisita's indices were used to determine thrips level of aggregation. Results showed significantly aggregated populations of thrips in both years. Formation of hot-spots in blueberry plantings seemed to be random. However, the formation of hot-spots was higher in places where more than seven thrips per day were captured on sticky traps, 5 to 7 d after the bloom begins. With these results, producers will be able to monitor thrips populations and locate and manage hot-spots before they become a more serious a problem on blueberry farms.     

Vertical distribution of codling moth adults in pheromone-treated and untreated plots

The vertical distribution of codling moth,Cydia pomonella (L.) within pheromone-treated and untreated apple and pear orchard canopies was determined using tethered virgin females, unbaited sticky traps, and blacklight observation of released moths. Mating of virgin females tethered at various heights in untreated orchard canopies increased with placement height from 1–4 m. Application of pheromone dispensers for mating disruption at 2 and 4 m above the ground greatly decreased mating. Greatest capture of males and females on unbaited sticky traps occurred at mid- and upper-canopy heights. Total capture of males and females in pheromone-treated plots was not statistically different than in untreated plots. The percentage of mated females captured on sticky traps did not vary with trap height or pheromone treatment. Released moths marked with flourescent powder and observed at dark with a blacklight indicated that moths are primarily distributed high in the canopy. However, males shifted to a position lower in the canopy when pheromone dispensers were placed 2.1 m above the ground. Results suggest that pheromone dispensers be placed in the upper canopy for optimal disruption of codling moth mating.     

Optimum spacing of pheromone traps for monitoring the coffee leaf miner Leucoptera coffeella

Pest monitoring with pheromone traps is affected mainly by factors such as trap placement and pest biology. The intertrap distance can affect the capture due to competition among traps that are placed at short distances. We studied the interference among pheromone traps used to monitor males of the coffee leaf miner, Leucoptera coffeella (Guérin‐Méneville) (Lepidoptera: Lyonetiidae), with traps placed at various distances. Using geostatistical analysis, we determined at what distance captures were independent from other traps. Traps were placed in groups of 12 with distances among traps per group either 2, 5, 10, 15, or 30 m. Traps were checked for males every 4 days during 16 days. We found interference between traps when intertrap distances were shorter than 10 m. The range and magnitude of spatial dependence varied considerably among each sampling date and wind direction. For directions of 45° and 135°, the traps should be placed 110 and 177 m apart, respectively, to obtain spatially independent counts and therefore representative samplings for assessing the insect population in the area. These results have implications for developing sampling plans for managing L. coffeella with pheromone traps; the spatial analysis indicated that a trap density of one pheromone trap for every 3.5–4 ha would be adequate for the monitoring of the coffee leaf miner.     

Spotted cutworm,Xestia c‐nigrum (L.) (Lepidoptera: Noctuidae) responses to sex pheromone and blacklight

Traps baited with the sex pheromone blend of (Z7)‐ and (Z5)‐tetradecenyl acetate captured significant numbers of male spotted cutworm moths, Xestia c‐nigrum (L.) compared to unbaited traps. Nearly no males were captured in traps baited with (Z7)‐tetradecenyl acetate, the major pheromone component. Antennae of spotted cutworm males responded to (Z7)‐, (E7)‐, (Z5)‐ and (E5)‐tetradecenyl acetate in the laboratory; however there was no response by moths in the field to the E isomers when presented in traps as major and minor components respectively of a binary blend or to the (E7) isomer as a single component. These findings clarify the makeup of a sex attractant that can be used for monitoring X. c‐nigrum on agricultural crops in Washington. However, multi‐year season‐long monitoring of spotted cutworm moths in Yakima Valley apple orchards revealed differential responses to pheromone and blacklight traps. A spring flight period showed a strong moth response to the pheromone compared to blacklight, while a later summer flight period showed a weak moth response to the pheromone relative to blacklight. At this time, we do not know which trap type might best indicate spotted cutworm abundance and risk to crops.     

Bat Response to Woodland Restoration within Urban Forest Fragments

In urban environments, woodland areas are typically fragmented and subject to invasive species encroachment, woody overgrowth, and natural succession. In response to negative impacts, conservationists and land managers have implemented restoration strategies to enhance the integrity of woodlands. Because woodland habitat is important for bats (Order Chiroptera), alterations to forest structures may affect how bats utilize forest fragments in urban environments. We evaluated relationships among restoration efforts, microhabitat characteristics and overall bat activity, and interspecific variation among bats in response to woodland characteristics. We monitored bats in nine woodland forest preserves representing various stages of restoration within the Chicago metropolitan area in 2004 and 2005. Overall bat activity was positively related to prescribed burning, invasive species removal, and small tree density (7.7‐20 cm dbh) and inversely related to shrub density and clutter at 0‐6 m heights. There was interspecific variation in response to alterations in woodland structure, with Lasiurus borealis (L. borealis) positively associated with small and medium (20.1‐33 cm) tree densities and inversely related to clutter at 0‐9 m; Myotis spp. positively associated with canopy cover, clutter at 6‐9 m, and small and medium tree densities; and Lasionycteris noctivagans (L. noctivagans) positively associated with more open forests. Eptesicus fuscus (E. fuscus) activity was not strongly associated with any measured vegetation variable. Our results demonstrate bats positively respond to some forms of woodland restoration in urban landscapes. However, species‐specific responses to vegetation differed and should be taken into consideration when developing management plans.     

Female sex pheromone of brinjal fruit and shoot borer,Leucinodes orbonalis (Lepidoptera: Pyralidae): trap optimization and application in IPM trials

Delta and wing traps baited with synthetic female sex pheromone of Leucinodes orbonalis Guenée were found to catch and retain ten times more moths than either Spodoptera or uni-trap designs. Locally-produced water and funnel traps were as effective as delta traps, although 'windows' cut in the side panels of delta traps significantly increased trap catch from 0.4 to 2.3 moths per trap per night. Trap catch was found to be proportional to the radius of sticky disc traps in the range 5-20 cm radius, discs with a 2.5 cm radius caught no moths. Wing traps placed at crop height caught significantly more moths than traps placed 0.5 m above or below the crop canopy. Replicated integrated pest management (IPM) trials (3 x 0.5 ha per treatment) were conducted in farmers fields with young and mature eggplant crops. Farmers applied insecticides at least three times a week in all check and IPM plots. In addition pheromone traps were placed out at a density of 100 per ha and infested shoots removed weekly in the 0.5 ha IPM plots. Pheromone trap catches were reduced significantly from 2.0 to 0.4 moths per trap per night respectively in check and IPM plots in a young crop and 1.1 to 0.3 moths per trap per night in check and IPM plots respectively in a mature crop. Fruit damage was significantly reduced from an average of 41.8% and 51.2% in check plots of young and mature crops respectively to 22% and 26.4 respectively in the associated IPM plots. Significant differences in pheromone trap catches and fruit damage were attained four and two weeks respectively after IPM treatments began in the mature crop whereas in the immature crop significant differences were not observed for the first eight to nine weeks respectively. The relative impact of removing infested shoots and mass trapping on L. orbonalis larval populations was not established in these trials but in both cases there was an estimated increase of approximately 50% in marketable fruit obtained by the combination of control techniques compared to insecticide treatment alone.     

Phenological and geographical relationships between catches of pea moth in sex-attractant traps

Traps containing a sex attractant of the pea moth (Cydia nigricana) were used to monitor numbers of male moths in individual fields in south-eastern and eastern England from 1976 to 1978 at 16 or more sites/yr. Data concerning catches at different sites on several occasions over the flight season, and dates on which a ‘threshold catch’ was achieved were examined, and were related weakly to site locations within areas. Area spray warnings, based on trap catches at a few sites within a large area, provide a less reliable indication of the need to spray than on-site monitoring (two traps) in each pea field. On-site monitoring may be improved by specialist interpretation of trap catches.     

Modelling fallen branch volumes in a temperate eucalypt woodland: implications for large senescent trees and benchmark loads of coarse woody debris

Fallen branches are a substantial component of coarse woody debris and a key ecological resource. The depletion of stocks of coarse woody debris since European settlement has contributed to the degradation of Australian grassy box woodlands, including the loss of biodiversity. Restoration options for remnant woodlands include the augmentation of coarse woody debris stocks. However, the extensive modification of grassy box woodlands has left few reference sites for establishing benchmarks to guide such restoration. In this paper we demonstrate a method for predicting fallen branch debris loads in the absence of reference sites, using data from a yellow box–red gum woodland. Our methodology is in two stages: first, the total volume of branch debris under individual trees was modelled; and second, these models were applied to groups of trees to predict stand‐level loads of fallen branch debris. Although the models were developed for yellow box–red gum woodlands, the methodology would be applicable to other communities that lack reference sites. Predicted benchmark loads of fallen branch debris for yellow box–red gum woodland were between 7.0 m³ ha^?1 and 11.9 m³ ha^?1. Large senescing trees contributed the bulk of fallen branch debris. Model predictions indicated a 100‐cm diameter at breast height (dbh) tree was 10 times more likely to produce debris than a 50‐cm dbh tree, and if debris was present a 100‐cm dbh tree produced approximately 10 times the volume of branch debris produced by a 50‐cm dbh tree. These results highlight the importance of large senescing trees for the production of fallen branch debris and support the keystone role of large trees within remnant woodlands, and the need to conserve these structures. Our results also support the active management of regrowth woodland stands to facilitate the progression of individual trees to maturity and senescence. In particular, thinning of regrowth stands may promote the growth of retained trees, ensuring they contribute to fallen branch debris stocks with a minimum time lag.     

Comparative efficacy of three suction traps for collecting phlebotomine sand flies (Diptera: Psychodidae) in open habitats

The efficacy of three suction traps for trapping phlebotomine sand flies (Diptera: Psychodidae) was compared. Traps were baited with Co₂ and used without any light source. CO₂‐baited CDC traps were evaluated either in their standard downdraft orientation or inverted (iCDC traps). Mosquito Magnet‐X (MMX) counterflow geometry traps were tested in the updraft orientation only. Both updraft traps (iCDC and MMX) were deployed with their opening ～10 cm from the ground while the opening of the downdraft (CDC) trap was ～40 cm above ground. Comparisons were conducted in two arid locations where different sand fly species prevail. In the Jordan Valley, 3,367 sand flies were caught, 2,370 of which were females. The predominant species was Phlebotomus (Phlebotomus) papatasi, Scopoli 1786 (>99%). The updraft‐type traps iCDC and MMX caught an average of 118 and 67.1 sand flies per trap night, respectively. The CDC trap caught 32.9 sand flies on average per night, significantly less than the iCDC traps. In the Judean desert, traps were arranged in a 3×3 Latin square design. A total of 565 sand flies were caught, 345 of which were females. The predominant species was P. (Paraphlebotomus) sergenti Parrot 1917 (87%). The updraft traps iCDC and MMX caught an average of 25.6 and 17.9 sand flies per trap per night, respectively. The CDC trap caught 7.8 sand flies on average per night, significantly less than the iCDC traps. The female to male ratio was 1.7 on average for all trap types. In conclusion, updraft traps deployed with their opening close to the ground are clearly more effective for trapping sand flies than downdraft CDC traps in open habitats.     

Effect of semiochemicals and trap height on catch of Neocerambyx raddei in Jilin province,China

We conducted experiments in Jilin, China, in 2011 and 2014 in forest stands dominated by mature Quercus mongolica Fisch. ex Ledeb. (Fagaceae) to test the effects of longhorn beetle pheromones, plant volatiles, and trap height on catch of Neocerambyx raddei (Blessig & Solsky) (formerly Massicus raddei) (Coleoptera: Cerambycidae) in traps. Traps captured 276 specimens of N. raddei in 2011 and 379 specimens in 2014 (384 females, 271 males). Ethanol was attractive to female but not male N. raddei. However, N. raddei was not attracted to any of the longhorn beetle pheromones tested, which included racemic 3‐hydroxyhexan‐2‐one, racemic 3‐hydroxyoctan‐2‐one, syn‐2,3‐hexanediols, anti‐2,3‐hexanediols, racemic E,Z‐fuscumol, racemic E,Z‐fuscumol acetate, and monochamol, nor was it attracted to 2‐methyl‐3‐buten‐2‐ol. Traps placed in the tree canopy captured significantly more beetles than did traps in the understorey. Our results suggest that surveys for N. raddei should use ethanol‐baited traps placed in the tree canopy. If sex or aggregation pheromones are identified for N. raddei in the future, we predict that attraction to them will be enhanced by the presence of ethanol.     

Influence of within-orchard trap placement on catch of codling moth (Lepidoptera: Tortricidae) in sex pheromone-treated orchards

The influence of trap placement on catches of codling moth, Cydia pomonella L., was examined in a series of studies conducted in orchards treated with Isomate-C Plus sex pheromone dispensers. Mark-recapture tests with sterilized moths released along the interface of pairs of treated and untreated apple and pear plots found that significantly more male but not female moths were recaptured on interception traps placed in the treated plots. In a second test, significantly higher numbers of wild male and female moths were caught on interception traps placed in treated versus untreated plots within a heavily infested orchard. The highest numbers of male moths were caught on traps placed along the interior edge of the treated plots. Trap position had no influence on the captures of female moths. In a third test, north-south transects of sex pheromone-baited traps were placed through adjacent treated and untreated plots that received a uniform release of sterilized moths. Traps on the upwind edge of the treated plots caught similar numbers of moths as traps upwind from the treated plots. Moth catch was significantly reduced at all other locations inside versus outside of the treated plots, including traps placed on the downwind edge of the treated plot. In a fourth test, five apple orchards were monitored with groups of sex pheromone-baited traps placed either on the border or at three distances inside the orchards. The highest moth counts were in traps placed at the border, and the lowest moth counts were in traps placed 30 and 50 m from the border. In a fifth test, the proportion of traps failing to catch any moths despite the occurrence of local fruit injury was significantly higher in traps placed 50 versus 25 m from the border. The implications provided by these data for designing an effective monitoring program for codling moth in sex pheromone-treated orchards are discussed.     

The ambrosia beetle Anisandrus maiche (Stark) is repelled by conophthorin and verbenone and attracted to ethanol in a dose-dependent manner

1. Anisandrus maiche (Stark) (Coleoptera: Curculionidae: Scolytinae) is a non-native ambrosia beetle recently detected in northwestern Indiana. There is a critical need for advanced methods to detect and manage this potentially destructive beetle. Identifying semiochemicals that function as attractants or repellents can inform management practices to protect high-value plantings of hardwood trees.
2. We evaluated the extent to which (S)-(−)-verbenone, (E)-(±)-conophthorin and ethanol influence trap capture of A. maiche using two trap types and heights. We also investigated the effect of ethanol release rate on trap capture.
3. Traps baited with ethanol alone captured the most beetles, while traps baited with (S)-(−)-verbenone or (E)-(±)-conophthorin alone captured few A. maiche, and each compound decreased capture when paired with ethanol lures.
4. There was no difference in mean capture of A. maiche between trap types across treatments, and the height of ethanol-baited traps did not influence the capture rate suggesting this species is widely distributed throughout the canopy.
5. Our results suggest that (S)-(−)-verbenone and (E)-(±)-conophthorin are effective repellents for A. maiche and a release rate of at least 3 g/day of ethanol enhances trap to capture.

     

Pheromone trap for the eastern tent caterpillar moth

The discovery that the eastern tent caterpillar Malacosoma americanum (F.) causes mare reproductive loss syndrome (MRLS), and thus has the potential to continue to result in major economic losses to the equine industry of Kentucky, has resulted in an intensive effort to identify practical means to monitor and control this defoliator, including these experiments to optimize a sex pheromone trap for this pest. A pheromone-baited delta trap with a large opening, such as InterceptST Delta, was more effective than other tested traps. Orange delta traps caught more moths than other tested colors. ETC males are caught at all tested heights within the tree canopy. For monitoring flights, setting traps at 1.5 m would allow easy counting of moths. A 9:1 blend of (E,Z)-5,7-dodecadienal (ETC-Ald) and (E,Z)-5,7-dodecadienol (ETC-OH) was most effective in capturing males. Increasing loading doses of a 3:1 blend (Ald:OH) resulted in the capture of increasing numbers of moths, but a 9:1 blend was more effective than 3:1 blend even at a nine-fold lower loading rate. Pheromone-impregnated white septa caught more moths than gray septa at the same loading dose. The advantages and limitations of using pheromone traps for monitoring M. americanum are discussed.     

Optimization of pheromone lure and trap design for monitoring the fir coneworm, Dioryctria abietivorella

The major components of the sex pheromone of Dioryctria abietivorella (Groté) (Lepidoptera: Pyralidae) were recently identified as (9Z,11E)‐tetradecadien‐1‐yl acetate (9Z,11E‐14:Ac) and a polyunsaturated, long‐chain hydrocarbon (3Z,6Z,9Z,12Z,15Z)‐pentacosapentaene (C25 pentaene). The optimal ratio of these components and the role of potential minor components were not fully determined in the initial short report on the pheromone's identification. We tested different ratios of the two major components loaded into grey halobutyl rubber septum dispensers, placed in sticky traps deployed in conifer breeding arboreta. The optimal ratio of the two components was 200 µg 9Z,11E‐14:Ac to 2000 µg C25 pentaene. (Z)‐9‐Tetradecen‐1‐yl acetate, which had been identified previously in female pheromone gland extracts, and five other potential minor pheromone components, were tested individually as additions to the optimized two‐component lure blend. None of the ternary blends were more attractive than the optimized two‐component blend, at the ratios tested. Two lure adjuvants, a UV stabilizer (Sumisorb 300) and the antioxidant butylated hydroxytoluene, added individually or together, did not affect the attractiveness of the optimized lure blend. The Pherotech diamond sticky trap baited with the optimized lure blend was the most effective trap design among eight types of sticky trap and a bucket style trap that were tested. Traps baited with synthetic lures were as attractive as traps baited with virgin female moths. The optimized two‐component lure blend in the Pherotech diamond trap is recommended for monitoring fir coneworm infestations. The availability of an effective synthetic pheromone opens the possibility for control tactics using mating disruption or attract‐and‐kill techniques.     

The development of an improved model trap for monitoring Ephestia cautella

Delta, Covered funnel and Uni-traps containing pheromone used for monitoring male Ephestia cautella (Walker) (Lepidoptera: Phycitidae) moths were compared in a wind tunnel in moving and still air. The shape and design of the traps and the form of pheromone plume emitted from them determined the moth's latency time, numbers orientating, alighting on the traps and captured. To improve trap design, the visual responses of the moths to rectangles of different colours and sizes and to brown and white stripes, showed that more moths were attracted to darker coloured 6×50 cm vertical rectangles on a white background and to 7.5 mm brown and white stripes. A cylindrical trap containing pheromone incorporating these features captured 90% and 80% of the moths released in the wind tunnel in moving and still air respectively, compared with 70% and 35% for the best commercial traps.