Review of Bacillus thuringiensis var. kurstaki (Btk) for use in forest pest management programs of Ontario - with special emphasis on the aquatic environment / by G.A. Surgeoner and M.J. Farkas.

Farkas, Martha J.; Surgeoner, G. A.

doi:10.5962/bhl.title.33510

Cited by 4 publications

(4 citation statements)

References 23 publications

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“…These results are worrying because these microbial insecticides are reported to be environmentally friendly and, at the same time, are surprising because C. xanthus is a non‐target species for these compounds. B. bassiana is not supposed to pose risk to aquatic compartments and Btk is specific to Lepidoptera and not Diptera, and have been for long considered safe toward non‐target aquatic insects . Nevertheless, effects on larval growth were not translated into differences in time to emergence in males or females, which suggests that decreased emergence, which for Btk was the most sensitive life history endpoint, is a result of reduced larval survival rather than delayed development, attesting by the efficacy of Bt‐based compounds as potent larvicides.…”

Section: Discussionmentioning

confidence: 99%

Toxicity of microbial insecticides toward the non‐target freshwater insect Chironomus xanthus

Dornelas

Sarmento

Silva

et al. 2019

Pest Management Science

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BACKGROUND Commercial formulations based on Bacillus thuringiensis subs. kurstaki (Btk) and Beauveria bassiana (Bb) are commonly used microbial insecticides in Brazil and other tropical regions. However, and despite being considered environmentally friendly, their use generates concerns regarding possible adverse ecological effects in freshwater ecosystems. Here, we evaluate the effects of these bioinsecticides on the tropical aquatic dipteran Chironomus xanthus under laboratory conditions. RESULTS After laboratory exposures to these compounds 48‐h median lethal concentration (LC50) values of 1534 μg a.i./L for Btk and of 6.35 μg a.i./L for Bb were estimated. Chronic assays revealed different sublethal effects: Btk‐based bioinsecticide exposure reduced C. xanthus growth [lowest observed effect concentration (LOEC) was 126 μg a.i./L for head width], decreased emergence rate (LOEC = 8 μg a.i./L) and increased immunological response (LOEC = 50 μg a.i./L) measured as total hemocyte count in larvae hemolymph. Exposure to low concentrations of Bb‐based insecticide also reduced C. xanthus growth (LOEC = 0.07 μg a.i./L for larvae body length measurements), and emergence rate (LOEC = 0.28 μg a.i./L), despite no clear effects on the total hemocyte counts. CONCLUSION Our results suggest that low concentrations of Btk and Bb bioinsecticides are toxic to C. xanthus. Given their widespread use and occurrence in tropical freshwater systems, research is needed to evaluate the potential effects of these compounds concerning natural freshwater insect communities and ecosystem functioning. © 2019 Society of Chemical Industry

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Section: Discussionmentioning

confidence: 99%

Toxicity of microbial insecticides toward the non‐target freshwater insect Chironomus xanthus

Dornelas

Sarmento

Silva

et al. 2019

Pest Management Science

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“…Neither of the forest insecticides currently being used in Canada's boreal forest (Btk and tebufenozide) pose a significant risk of direct harm to fish at expected environmental concentrations (Surgeoner and Farkas 1990;Wing and Aller 1990;Steedman and Morash 2001). The herbicide glyphosate, and (or) its forestry formulations containing the polyethoxylated amine surfactant (POEA), can be toxic to fish but many studies have demonstrated that expected field concentrations of glyphosate are unlikely to cause direct harmful effects on fish (Hildebrand et al 1982;Solomon and Thompson 2003).…”

Section: Fishmentioning

confidence: 99%

Impacts and prognosis of natural resource development on aquatic biodiversity in Canada’s boreal zone

et al. 2013

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Conservation efforts to sustain water resources and aquatic biodiversity in boreal watersheds will require reliable information on the recent status of various indicator species and an improved understanding of the risks to aquatic biodiversity posed by resource development activities. We reviewed the recent state of knowledge on the responses of aquatic biodiversity to forest management, pulp and paper mill effluents, hydroelectric impoundments, mining of minerals and metals, oil sands extractions, and peat mining and offer a prognosis for aquatic biodiversity under each of these environmental stressors. Despite the prevalence of natural resource development in Canada’s largest forest ecosystem, there was a limited amount of published literature on the effects of many of the disturbance types on various indicators of aquatic biodiversity, making it difficult to produce a current and reliable status assessment. Across most of the boreal zone, there is a lack of coordinated, consistent data collection for many of the bioindicators and disturbance types discussed in this review. Forecasting the future state of aquatic biodiversity across the boreal zone is challenged by increasing natural resource development and its interactions with other stressors, especially climate change. The cumulative effects of multiple stressors coupled with resource development activities in boreal watersheds remain largely unknown. More importantly, the ecological thresholds for these cumulative effects (that is, the point at which aquatic ecosystems and their biodiversity cannot recover to a desired state within a reasonable time frame) are also unknown and remain gaps in our knowledge. The recent literature identifies a number of risks to aquatic biodiversity at local (tens of square kilometres) to regional (hundreds of square kilometres) scales associated with natural resource development. There are indications that many of these risks can be minimized by “greener” technologies for resource development and reclamation, practical conservation planning and regulation, and increased stewardship in watershed management, although the effectiveness of many of these measures cannot yet be assessed from the published literature.

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“…Bt has been shown to have no adverse effects on parasitoid development or its emergence when used against pest populations (Weseloh and Andreadis, 1982;Ulpah and Kok, 1996;Oluwafemi et al, 2009). Surgeoner and Farkas (1990) have recommended the use of Bt insecticide, such as Dipel, for use in integrated pest management programs and they have also shwed that it is harmless to most of the beneficials tested. Oluwafemi et al (2009) have reported that a combination of Bt with H. hebetor as a biological control agent, resulted in successful control of Plodia interpunctella population and has recommended the use of Bt in combination with a parasitoid for the control of other lepidopteran pests.…”

Section: Introductionmentioning

confidence: 99%

Host location and acceptance by parasitoid, Habrobracon hebetor and effect of varying Bacillus thuringiensis treatment against rice moth, Corcyra cephalonica

Mathew¹,

Singh²,

Tripathi

2018

Journal of Biological Control

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The combined effect of microbial pesticide, Bacillus thuringiensis Berliner (Bt), and insect parasitoid, Habrobracon hebetor Say (Hymenoptera: Braconidae) was evaluated for the management of rice moth, Corcyra cephalonica (Stainton) (Lepidoptera: Pyralidae). This parasitoid is very useful in testing host-parasitoid interaction due to its high fecundity and short generation time. The host location and acceptance by parasitoid female, investigated by choice and no choice tests, showed marked preference towards later host instar larvae of C. cephalonica. Parasitoid induced mortality of Bt-intoxicated and Bt-reared host larvae was also investigated. C. cephalonica mortality was highest (72.00 ± 3.26%) and synergistic when host larvae were exposed to acute Bt treatment in conjunction with the parasitoid. A combined treatment of Bt with H. hebetor is an effective strategy in integrated pest control programmes of C. cephalonica and other stored grain pests.

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Review of Bacillus thuringiensis var. kurstaki (Btk) for use in forest pest management programs of Ontario - with special emphasis on the aquatic environment / by G.A. Surgeoner and M.J. Farkas.

Cited by 4 publications

References 23 publications

Toxicity of microbial insecticides toward the non‐target freshwater insect Chironomus xanthus

Toxicity of microbial insecticides toward the non‐target freshwater insect Chironomus xanthus

Impacts and prognosis of natural resource development on aquatic biodiversity in Canada’s boreal zone

Host location and acceptance by parasitoid, Habrobracon hebetor and effect of varying Bacillus thuringiensis treatment against rice moth, Corcyra cephalonica

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