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Lincoln, Canada

Carleton R.D.,Natural Resources Canada | Carleton R.D.,Forest Protection Ltd | Heard S.B.,University of New Brunswick | Silk P.J.,Natural Resources Canada
PLoS ONE | Year: 2013

Estimation of pest density is a basic requirement for integrated pest management in agriculture and forestry, and efficiency in density estimation is a common goal. Sequential sampling techniques promise efficient sampling, but their application can involve cumbersome mathematics and/or intensive warm-up sampling when pests have complex within- or between-site distributions. We provide tools for assessing the efficiency of sequential sampling and of alternative, simpler sampling plans, using computer simulation with "pre-sampling" data. We illustrate our approach using data for balsam gall midge (Paradiplosis tumifex) attack in Christmas tree farms. Paradiplosis tumifex proved recalcitrant to sequential sampling techniques. Midge distributions could not be fit by a common negative binomial distribution across sites. Local parameterization, using warm-up samples to estimate the clumping parameter k for each site, performed poorly: k estimates were unreliable even for samples of n∼100 trees. These methods were further confounded by significant within-site spatial autocorrelation. Much simpler sampling schemes, involving random or belt-transect sampling to preset sample sizes, were effective and efficient for P. tumifex. Sampling via belt transects (through the longest dimension of a stand) was the most efficient, with sample means converging on true mean density for sample sizes of n∼25-40 trees. Pre-sampling and simulation techniques provide a simple method for assessing sampling strategies for estimating insect infestation. We suspect that many pests will resemble P. tumifex in challenging the assumptions of sequential sampling methods. Our software will allow practitioners to optimize sampling strategies before they are brought to real-world applications, while potentially avoiding the need for the cumbersome calculations required for sequential sampling methods. © 2013 Carleton et al. Source


Bagherpour A.,University of New Brunswick | Holloway G.,University of New Brunswick | McLeod I.M.,Forest Protection Ltd
American Society of Mechanical Engineers, Fluids Engineering Division (Publication) FEDSM | Year: 2010

An important characteristic of sprays is their statistical distribution of droplet sizes. Knowledge of the droplet distribution is particularly important for pesticide applications because droplet size affects droplet trajectory, probability of contact with foliage, and the biological dose to target pests. This work describes an experimental study of an aerial spray application in a wind tunnel environment at realistic flight speeds (67 m=s) using a full-scale rotary atomizer turning at 8600 rpm. Comparative measurements of water droplet velocity and diameter were made a 3 component Artium Phase Doppler Interferometer (PDI) and a Sympatec Helos Vario Laser Diffraction (LD) instrument. Distance from the atomizer to the measurement cross section was varied to observe the effects of the atomizer wake on the results. Copyright © 2010 by ASME. Source


Carleton R.D.,Forest Protection Ltd | Carleton R.D.,University of New Brunswick | Johns R.C.,Natural Resources Canada | Edwards B.V.,Forest Protection Ltd | And 3 more authors.
Canadian Entomologist | Year: 2015

Field studies were carried out to assess diel activity patterns of the balsam gall midge, Paradiplosis tumifex Gagné (Diptera: Cecidomyiidae) in 2012, and its inquiline, Dasineura balsamicola (Lintner) (Diptera: Cecidomyiidae) in 2013, in a young balsam fir (Abies balsamea (Linnaeus) Miller) stand in New Brunswick, Canada. Both gallmaker and inquiline are most active during the afternoon/evening hours (17:00-22:00 hours). Male gallmaker activity was largely confined to the space below the crown and typically involved short periods of flight of <30 seconds. Calling and mating by the gallmaker occurred at ground level and were followed by dispersal of females to the vegetative crown. Female gallmakers were typically observed in the tree crown beginning in early afternoon, with peak oviposition occurring between 20:00 and 21:00 hours. Female inquilines displayed similar activity patterns, although no calling or mating were observed. Moreover, inquiline flight and foraging for oviposition sites were more active than the gallmaker, with shorter rest periods and more buds visited than the gallmaker. Our results indicate that population monitoring should focus on female gallmakers as they fly during the evening. Also, before any treatment application, care should be taken to accurately identify the insects to ensure that the inquiline is not inadvertently killed. © Her Majesty the Queen in Right of Canada 2014. Source


Johns R.C.,Natural Resources Canada | Johns R.C.,University of New Brunswick | Edwards S.,University of New Brunswick | Carleton D.,University of New Brunswick | And 4 more authors.
Entomologia Experimentalis et Applicata | Year: 2015

Field surveys were carried out to assess the effects of intra-tree variation in developing shoot length within and among crown levels on the density and abundance of the balsam shoot-boring sawfly, Pleroneura brunneicornis Rohwer (Hymenoptera: Xyelidae), in young balsam fir, Abies balsamea (L.) Mill. (Pinaceae). Overall, cardinal direction had no influence on shoot-borer density or abundance; however, the highest percentage and abundance of bored shoots occurred on intermediate-sized shoots within the crown (i.e., in the mid-crown and on the distal-lateral and medial-lateral shoots). Comparatively, few shoot borers occurred in the upper or lower crown levels, or on the relatively large terminal shoots within branches. This distribution appears indicative of the higher suitability of intermediate-sized shoots within hosts for either egg lay or larval performance. Results of this study are most consistent with predictions of the 'optimal module size' hypothesis, which posits that herbivore responses to plant module size should reflect the balance of tradeoffs between utilizing relatively large, nutritious shoots vs. small, more easily exploited shoots. © 2015 The Netherlands Entomological Society. Source

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