scholarly journals Biological control of mites in European vineyards and the impact of natural vegetation

2010 ◽  
pp. 399-407 ◽  
Author(s):  
Carlo Duso ◽  
Serge Kreiter ◽  
Marie-Stéphane Tixier ◽  
Alberto Pozzebon ◽  
Valeria Malagnini
Plants ◽  
2021 ◽  
Vol 10 (11) ◽  
pp. 2411
Author(s):  
Hamada E. Ali ◽  
Solveig Franziska Bucher

Land-use changes have huge impacts on natural vegetation, especially megaprojects, as the vegetation layer is destroyed in the course of construction works affecting the plant community composition and functionality. This large-scale disturbance might be a gateway for the establishment of invasive plant species, which can outcompete the natural flora. In contrast, species occurring in the area before the construction are not able to re-establish. In this study, we analyzed the impact of a pipeline construction on a wetland nature reserve located in northern Egypt. Therefore, we analyzed the plant species occurrence and abundance and measured each plant species’ traits before the construction in 2017 as well as on multiple occasions up to 2 years after the construction had finished on altogether five sampling events. We found that the construction activity led to the establishment of an invasive species which previously did not occur in the area, namely, Imperata cylindrica, whereas five species (Ipomoea carnea, Pluchea dioscoridis, Polygonum equisetiforme, Tamarix nilotica, and Typha domingensis) could not re-establish after the disturbance. The functionality of ecosystems assessed via the analysis of plant functional traits (plant height, specific leaf area, and leaf dry matter content) changed within species over all sampling events and within the community showing a tendency to approximate pre-construction values. Functional dispersion and Rao’s quadratic diversity were higher after the megaproject than before. These findings are important to capture possible re-establishment and recovery of natural vegetation after construction and raise awareness to the impact of megaprojects, especially in areas which are high priority for conservation.


Author(s):  
Khalid S. Alshallash Khalid S. Alshallash

In four glasshouse experiments, the effectiveness of the adult green dock beetle Gastrophysa viridula (Coleoptera: Chrysomelidae), at the effective number of applied individuals, for use as a biological control agent of curled dock, Rumex crispus (Polygonaceae) were studied. The feeding of the beetle was investigated at four different numbers of beetle (0, 1, 2, 3) and at four seedling growth stages of the plant, defined by the average of leaf area per plant (1-1.22 , 2-4.45, 3-11.56, and 4-71.52 cm2/plant). Grazing by one, two or three dock beetles did not result in a significant reduction in dock dry weight or shoot numbers at the youngest growth stage. However, both at later seedling growth stages were significantly affected (P ? 0.0001), at any beetles number. The increase of beetle numbers caused nonsignificant increased effect, in some trials, confirming the impact of a single beetle. Three months after beetle grazing, dock seedlings of first, second and third growth stages were not able to regrow, however, some plants at the 4th growth stage, re-emerged. This suggested that the highest effect of beetle's feeding occurs on the early seedling stages. Statistical analysis showed a positive correlation (0.77) between dry weight and shoot number at all the four seedling growth stages, thus confirming the impact of the beetle on both the dry weight and shoot numbers. Combining beetle grazing with other control methods at older dock seedling stages could, therefore, provide better suppression


Forests ◽  
2020 ◽  
Vol 11 (2) ◽  
pp. 129 ◽  
Author(s):  
Anna Żółciak ◽  
Katarzyna Sikora ◽  
Marta Wrzosek ◽  
Marta Damszel ◽  
Zbigniew Sierota

This review aims to identify possible causes of differing effectiveness of artificial biological control of Heterobasidion root rot by the saprotrophic fungus Phlebiopsis gigantea. We describe published information in terms of pathogen–competitor relationships and the impact of environmental and genetic factors. We also revisit data from original research performed in recent years at the Forest Research Institute in Poland. We hypothesized that, in many cases, competition in roots and stumps of coniferous trees between the necrotrophic Heterobasidion spp. and the introduced saprotroph, Phlebiopsis gigantea, is affected by growth characteristics and enzymatic activity of the fungi, the characteristics of the wood, and environmental conditions. We concluded that both wood traits and fungal enzymatic activity during wood decay in roots and stumps, and the richness of the fungal biota, may limit biological control of root rot. In addition, we identify the need for research on new formulations and isolates of the fungal competitor, Phlebiopsis gigantea, as well as on approaches for accurately identifying the infectious threat from pathogens.


The Holocene ◽  
2020 ◽  
Vol 30 (8) ◽  
pp. 1101-1114 ◽  
Author(s):  
Ricardo Moreno-Gonzalez ◽  
Thomas Giesecke ◽  
Sonia L Fontana

Land-use change in the form of extensive Pinus plantations is currently altering the natural vegetation cover at the forest–steppe ecotone in northern Patagonia. Providing recommendations for conservation efforts, with respect to this recent and earlier land-use changes, requires a longer time perspective. Using pollen analysis, we investigated to what degree the colonization of the area by Euro-American settlers changed the forest composition and the vegetation cover, and to explore the spread of the European weed Rumex acetosella. This study is based on short sediment cores from six lakes in the Araucaria araucana forest region, across the vegetation gradient from the forest to the steppe. Results document that although Araucaria araucana has been extensively logged elsewhere, near the investigated sites, populations were rather stable and other elements of the vegetation changed little with the initiation of Euro-American settlements. A reduction of Nothofagus dombeyi-type pollen occurred at some sites presumably due to logging Nothofagus dombeyi trees, while toward the steppe, Nothofagus antarctica shrubs may have been removed for pasture. The appearance of Rumex acetosella pollen is consistent with the initiation of land use by Euro-American settlers in all cores, probably indicating the onset of animal farming. The rise of the Rumex acetosella pollen curve during the 1950s marks more recent land-use change. These observations indicate that the spread and local expansion of the weed requires disturbance. Overall, the study shows that the initial colonization of the area by Euro-American settlers had little effect on the natural vegetation structure, while developments since the 1950s are strongly altering the natural vegetation cover.


Insects ◽  
2019 ◽  
Vol 10 (8) ◽  
pp. 226 ◽  
Author(s):  
Dirk Babendreier ◽  
Min Wan ◽  
Rui Tang ◽  
Rui Gu ◽  
Justice Tambo ◽  
...  

The impact and sustainability of two interventions that have been formulated to introduce integrated pest management (IPM) into rice and maize crops in Southwestern China, Laos, and Myanmar between 2011 and 2016, and were assessed at the end of 2017. From 22 Trichogramma rearing facilities established during the interventions, 11 were still producing substantial quantities of biocontrol agents 1.5 years after project support had ended, while seven had stopped operations completely, and four were doing stock rearing only. Through the implementation of biological control-based IPM, slightly higher yields were achieved in maize and rice (4–10%), when compared to control farmers, but the difference was not statistically significant. However, the use of pesticides nearly halved when farmers started using Trichogramma egg-cards as a biological control agent. Support from either public or private institutions was found to be important for ensuring the sustainability of Trichogramma rearing facilities. Many of the suggested IPM measures were not adopted by smallholder farmers, indicating that the positive impacts of the interventions mostly resulted from the application of Trichogramma biological control agents. The following assessment suggests that further promotion of IPM adoption among farmers is needed to upscale the already positive effects of interventions that facilitate reductions in synthetic pesticide use, and the effects on sustainable agricultural production of rice and maize in the target area more generally.


2020 ◽  
Author(s):  
Andrew C. Wylie ◽  
Zamir K. Punja

Biological control of plant diseases is important in organic greenhouse vegetable production where fungicide use is limited. Organic producers employ microbially-diverse substrates, including composts, as media for plant growth. Previous research into the impact of vermicompost on the efficacy of applied biocontrol agents is limited. An in vitro assay was developed to test the efficacy of two biological control agents in a competitive microbial background. Suppression of the pathogen Fusarium oxysporum f. sp. radicis-cucumerinum (Forc) by Clonostachys rosea f. catenulata (Gliocladium catenulatum strain J1446 (Prestop®) and Bacillus subtilis strain QST 713 (Rhapsody®), was assessed on agar media amended with aerated vermicompost tea (ACT). Pathogen growth was reduced more by C. rosea than ACT alone and C. rosea was equally effective when combined with ACT. In contrast, B. subtilis reduced pathogen growth less than ACT, and when combined, reduced pathogen growth not more than ACT alone. Both biocontrol agents were similarly tested with ACT against Forc and Rhizoctonia solani on cucumber and radish. Additive, neutral, and antagonistic responses, depending on host, pathogen, and biocontrol agent, were observed. ACT alone provided more consistent disease suppression on cucumber compared with B. subtilis or C. rosea. In combination, disease suppression was most often better than each biocontrol alone but not better than ACT alone. ACT had antagonistic or additive interactions with C. rosea in the radish/R. solani pathosystem, depending on the experiment. The specific and general suppression of plant diseases by biological control agents in microbially-rich environments is variable and requires further study.


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