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      A major forest insect pest, the pine weevil Hylobius abietis, is more susceptible to Diptera‐ than Coleoptera‐targeted Bacillus thuringiensis strains


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          The pine weevil ( Hylobius abietis) is a major forest regeneration pest causing high levels of seedling mortality and economic losses. Current management relies on silviculture, stem coatings and insecticides. Here we evaluated for the first time the effects of Bacillus thuringiensis ( Bt) strains on H. abietis adults: two producing the Coleoptera‐targeted toxins Cry3Aa ( Bt tenebrionis NB‐176) and Cry8Da ( Bt galleriae SDS‐502), and one producing the Diptera‐targeted Cry10A ( Bt israelensis AM65‐52). Choice and nonchoice assays using individual and mixtures of Bt formulations, containing these strains respectively, were conducted.


          We found that Bt had toxic and lethal effects on H. abietis, but effects varied with strain and formulation concentration. The Diptera‐targeted Bt israelensis had the most negative effects on weevil weight, feeding and mortality (70–82% feeding reduction, 65–82% greater mortality than control), whereas the effect was lower for the Coleoptera‐specific Bt tenebrionis (38–42%; 37–42%) and Bt galleriae (11–30%; 15–32%). Reduced weevil feeding was observed after 3 days, and the highest mortality occurred 7–14 days following Bt exposure. However, we found no synergistic toxic effects, and no formulation combination was better than Bt israelensis alone at reducing consumption and survival. Also, pine weevils were not deterred by Bt, feeding equally on Bt‐treated and non‐ Bt treated food.


          There is potential to develop forest pest management measures against H. abietis that include Bt, but only the Diptera‐targeted Bt israelensis would provide effective seedling protection. Its Diptera‐specificity may need reconsideration, and evaluation of other Bt strains/toxins against H. abietis would be of interest. © 2020 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.


          Effects of Bacillus thuringiensis on the pine weevil Hylobius abietis were evaluated for the first time. A Diptera‐targeted strain was most toxic and could enhance forest protection against H. abietis.

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          Most cited references54

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          Fitting Linear Mixed-Effects Models Using lme4

          Maximum likelihood or restricted maximum likelihood (REML) estimates of the parameters in linear mixed-effects models can be determined using the lmer function in the lme4 package for R. As for most model-fitting functions in R, the model is described in an lmer call by a formula, in this case including both fixed- and random-effects terms. The formula and data together determine a numerical representation of the model from which the profiled deviance or the profiled REML criterion can be evaluated as a function of some of the model parameters. The appropriate criterion is optimized, using one of the constrained optimization functions in R, to provide the parameter estimates. We describe the structure of the model, the steps in evaluating the profiled deviance or REML criterion, and the structure of classes or types that represents such a model. Sufficient detail is included to allow specialization of these structures by users who wish to write functions to fit specialized linear mixed models, such as models incorporating pedigrees or smoothing splines, that are not easily expressible in the formula language used by lmer. Journal of Statistical Software, 67 (1) ISSN:1548-7660
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            glmmTMB balances speed and flexibility among packages for zero-inflated generalized linear mixed modeling

            Count data can be analyzed using generalized linear mixed models when observations are correlated in ways that require random effects. However, count data are often zero-inflated, containing more zeros than would be expected from the typical error distributions. We present a new package, glmmTMB, and compare it to other R packages that fit zero-inflated mixed models. The glmmTMB package fits many types of GLMMs and extensions, including models with continuously distributed responses, but here we focus on count responses. glmmTMB is faster than glmmADMB, MCMCglmm, and brms, and more flexible than INLA and mgcv for zero-inflated modeling. One unique feature of glmmTMB (among packages that fit zero-inflated mixed models) is its ability to estimate the Conway-Maxwell-Poisson distribution parameterized by the mean. Overall, its most appealing features for new users may be the combination of speed, flexibility, and its interface’s similarity to lme4. The R journal, 9 (2) ISSN:2073-4859
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              Insecticidal activity of Bacillus thuringiensis crystal proteins.

              Published data on insecticidal activity of crystal proteins from Bacillus thuringiensis are incorporated into the Bt toxin specificity relational database. To date, 125 of the 174 holotype known toxins have been tested in approximately 1700 bioassays against 163 test species; 49 toxins have not been tested at all; 59 were tested against 71 Lepidoptera species in 1182 bioassays; 53 toxins were tested against 23 Diptera species in 233 bioassays; and 47 were tested against 39 Coleoptera species in 190 bioassays. Activity spectra of the tested toxins were summarized for each order. Comparisons of LC(50) values are confounded by high variability of the estimates, mostly due to within-species variation in susceptibility, and errors associated with estimation of toxin protein content. Limited analyses suggest that crystal protein toxicity is not affected by quarternary toxin rank or host used for gene expression, but that pre-ingestion treatment by solubilization or enzymatic processing has a large effect. There is an increasing number of toxin families with cross-order activity, as 15 of the 87 families (secondary rank) that are pesticidal are active against more than one order. Cross-order activity does not threaten environmental safety of B. thuringiensis-based pest control because toxins tend to be much less toxic to taxa outside the family's primary specificity range.

                Author and article information

                Pest Manag Sci
                Pest Manag Sci
                Pest Management Science
                John Wiley & Sons, Ltd. (Chichester, UK )
                02 November 2020
                March 2021
                : 77
                : 3 ( doiID: 10.1002/ps.v77.3 )
                : 1303-1315
                [ 1 ] Department of Ecology Swedish University of Agricultural Sciences (SLU) Uppsala Sweden
                [ 2 ] Department of Plant Protection University of Agricultural Sciences and Veterinary Medicine of Cluj‐Napoca (USAMV Cluj Napoca) Cluj‐Napoca Romania
                [ 3 ] SweTree Technologies AB Umeå Sweden
                Author notes
                [*] [* ] Correspondence to: A Puentes, Department of Ecology, Swedish University of Agricultural Sciences (SLU), Box 7044, SE‐75007 Uppsala, Sweden. E‐mail: adriana.puentes@ 123456slu.se

                Author information
                © 2020 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

                This is an open access article under the terms of the http://creativecommons.org/licenses/by-nc/4.0/ License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited and is not used for commercial purposes.

                : 22 July 2020
                : 05 October 2020
                : 19 October 2020
                Page count
                Figures: 6, Tables: 6, Pages: 13, Words: 10524
                Funded by: Stora Enso Oyj , open-funder-registry 10.13039/501100009236;
                Research Article
                Research Articles
                Custom metadata
                March 2021
                Converter:WILEY_ML3GV2_TO_JATSPMC version:5.9.7 mode:remove_FC converted:19.02.2021

                Pests, Diseases & Weeds
                biopesticides,forest pest,forest regeneration,insecticidal toxins,pest management,plant protection


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