Comparing predictions from mixed model equations with host range determinations from historical disease evaluation data of two previously released weed biological control pathogens

Weedy invasive Cirsium spp. are widespread in temperate regions of North America and some of their biological control agents have attacked native Cirsium spp. A phylogenetic tree was developed from DNA sequences for the internal transcribed spacer and external transcribed spacer regions from native and non-native Great Plains Cirsium spp. and other thistles to determine if host specificity follows phylogeny. The monophyly of Cirsium spp. and Carduus within the tribe Cardinae was confirmed with native North American and European lineages of the Cirsium spp. examined. We did not detect interspecific hybridization between the introduced invasive and the native North American Cirsium spp. Selected host-biological control agent interactions were mapped onto the phylogenic tree derived by maximum likelihood analysis to examine the co-occurrence of known hosts with biological control agents. Within Cirsium-Cardueae, the insect biological control agents do not associate with host phylogenetic lines. Thus, more comprehensive testing of species in host-specificity trials, rather than relying on a single representative of a given clade may be necessary; because the assumption that host-specificity follows phylogeny does not necessarily hold. Since the assumption does not always hold, it will also be important to evaluate ecological factors to provide better cues for host specificity.

show abstract

“…in California and extensive analysis using molecular marker data support that the rust strain only affected Carduus spp. [ 40 , 41 ].…”

Section: Discussionmentioning

confidence: 99%

Phylogeny of Cirsium spp. in North America: Host Specificity Does Not Follow Phylogeny

Slotta

Horvath

Foley

2012

Plants

View full text Add to dashboard Cite

show abstract

“…Notably, this involves ascertaining the host spectra, so as not to affect the crops and to measure the impact of inundative inoculation of a strain or set of fungal strains on the wider environment. It can be derived from field observations but also by using of predictive models designed to assess the risk of misuse of a pathogen to control a weed (Barton 2012;Berner and Bruckart 2012). This evaluation should also focus on estimating the cost/benefit ratio of biocontrol versus chemical and/or mechanical approaches.…”

Section: Knowledge Gaps and Future Challenges In Weed Control By Fungimentioning

confidence: 99%

“…All of these impacts should be described. The data acquired should feed into models to predict the bioherbicide and weed population fate under different edapho-climatic conditions and cropping systems (Berner and Bruckart 2012;Berner and Cavin 2012;Colbach et al 2014). Second, research should focus on broad-spectrum rather than solely on highly host-specific bioherbicides.…”

Section: Knowledge Gaps and Future Challenges In Weed Control By Fungimentioning

confidence: 99%

Biodiversity-based options for arable weed management. A review

Petit

Cordeau

Chauvel

et al. 2018

Agron. Sustain. Dev.

View full text Add to dashboard Cite

In the context of a shift towards pesticide reduction in arable farming, weed management remains a challenging issue. Integrated Weed Management currently recommends agronomic practices for weed control, but it does not integrate the use of biodiversitybased options, enhancing the biological regulation of weeds. Here, wereview existing knowledge related to three potentially beneficial interactions, of crop-weed competition, weed seed granivory, and weed interactions with pathogenic fungi. Our main finding are the following : (1) promoting cropped plant-weed competition by manipulating cropped cover could greatly contribute to weed reduction ; (2) weed seed granivory by invertebrates can significantly lower weed emergence, although this effect can be highly variable because seed predation is embedded within complex multitrophic interactions that are to date not fully understood ; (3) a wide range of fungi are pathogenic to various stages of weed development, but strain efficacy in field trials does not often match that in controlled conditions. We present a framework that superimposes biodiversity-based options for weed biocontrol on a classical Integrated Weed Management system. We then describe the current state of knowledge on interactions between agronomic practices and the organisms at play and between the different biological components of the system. We argue that further advances in our understanding of biodiversity-based options and their performance for weed biocontrol will require farm-scale experimental trials.

show abstract

“…(Aveskamp et al, 2010) is spread worldwide in agriculture, horticulture and forestry. Taxonomically, B. exigua is a group of more than ten species (Aveskamp et al, 2010;Berner and Bruckart, 2015). Thus, morphological determination is often supported by molecular methods.…”

Section: Introductionmentioning

confidence: 99%

“…Thus, morphological determination is often supported by molecular methods. Many methods for identifying the types of Boeremia/Phoma are based on genes or combinations of genetic sequences such as the ITS and β-tubulin genes (Aveskamp et al, 2010;Berner and Bruckart, 2015;Kowalski et al, 2019). Cotton production is greatly influenced by biotic factors that causes significant yield losses (up to 10-30%) (Tarazi et al, 2020).…”

Section: Introductionmentioning

confidence: 99%

Boeremia Exigua Leaf Spot: A New Emerging Threat to Gossypium hirsutum L. in Pakistan

et al. 2022

View full text Add to dashboard Cite

Cotton is grown all over the world including Asian countries. Severe foliar disease symptoms were observed on cotton in fields from different districts of cotton zone of the province of Punjab, Pakistan. Infected plant leaves were sampled from various areas and processed for the isolation of the causal organism. Fungal isolates were identified morphologically. The conidia of the fungus were observed oblong to ellipsoid, hyaline, and aseptate, but occasionally 1-septate with dimensions ranging from 2.7 to 7.8 × 1.6 to 3.5 μm. A total of two isolates were characterized further for genetic diversity. Both the isolates showed moderate reactions to the NaOH test for E metabolite. The pathogen was morphologically identified as Boeremia exigua. Further, the internal transcribed spacer region (ITS) and TUB gene of the fungal isolates were amplified and analyzed. The sequence of partial ITS and TUB showed 99% homology with the isolates of B. exigua. The pathogenicity test was performed on three months old cotton plants by using two isolates of B. exigua. After 15 days of inoculation, necrotic spots started developing on the leaves that were very similar to those observed in the field. The fungal pathogen was re-isolated from the leaves of all the inoculated plants, identified morphologically following Koch's postulates. This disease might be a potential threat to cotton production in Pakistan in the future. However, further studies are required to know the virulence, behavior, alternate hosts, and spreading nature of the pathogen.

show abstract

Comparing predictions from mixed model equations with host range determinations from historical disease evaluation data of two previously released weed biological control pathogens

Cited by 5 publications

References 31 publications

Phylogeny of Cirsium spp. in North America: Host Specificity Does Not Follow Phylogeny

Phylogeny of Cirsium spp. in North America: Host Specificity Does Not Follow Phylogeny

Biodiversity-based options for arable weed management. A review

Boeremia Exigua Leaf Spot: A New Emerging Threat to Gossypium hirsutum L. in Pakistan

Contact Info

Product

Resources

About