BACKGROUND 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. RESULTS 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. CONCLUSION 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.

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The pine weevil, Hylobius abietis L., is a pest of economic importance causing massive damage to conifer seedlings planted on reforestation sites. The lack of effective methods to prevent establishment of H. abietis in newly-harvested sites makes it a threat to European forests. The biology and ecology of the pine weevil have been intensely studied through the years. However, in light of current and future climate change much of the knowledge gathered thus far may need to be re-evaluated under these new conditions. Changes in temperature and other climatic variables may strongly change, for example, the development of the weevil and its distribution. Such changes may result in higher population numbers and increase the feeding pressure on newly planted seedlings, thus making it a novel pest in certain areas or increasing its pest status in others. There is a need to synthesize our current understanding on the biology, behavior and methods of damage control by the pine weevil H. abietis, in order to identify knowledge gaps and propose new management practices. In this review, we present such an overview and provide several examples on how this knowledge could be expanded or used to meet future challenges.