234 research outputs found
An Intimate Relationship Between Eriophyoid Mites and Their Host Plants - A Review
Eriophyoid mites (Acari Eriophyoidea) are phytophagous arthropods forming intimate
relationships with their host plants. These mites are associated with annual and perennial
plants including ferns, and are highly specialized with a dominant monophagy. They
can be classified in different ecological classes, i.e., vagrant, gall-making and refugeseeking
species. Many of them are major pests and some of them are vectors of plant
pathogens. This paper critically reviews the knowledge on eriophyoids of agricultural
importance with emphasis on sources for host plant resistance to these mites. The
role of species belonging to the family Eriophyidae as vectors of plant viruses is
discussed. Eriophyoid-host plant interactions, the susceptibility within selected crops
and main host plant tolerance/resistance mechanisms are discussed. Fundamental
concepts, subjects, and problems emerged in this review are pointed out and studies
are suggested to clarify some controversial points
Airborne pollen can affect the abundance of predatory mites in vineyards: implications for conservation biological control strategies
BACKGROUND
The importance of pollen as alternative food for generalist phytoseiid mites occurring in vineyards has been investigated in northeastern Italy. We compared pollen and phytoseiid abundance in four vineyards and in plots located at different distance from flowering hop plants. Pollen (Carpinus betulus and Typha spp.) was sprayed onto the foliage to evaluate the potential impact of this food source on predatory mite abundance. Finally, grass management was investigated to analyze the effect of a reduced mowing frequency on predatory mite population densities.
RESULTS
Arboreal pollen was found mostly during the spring and the grapevine blossoming period. Nonarboreal pollen dominated throughout the growing seasons. In vineyards, the abundance of Amblyseius andersoni, Kampimodromus aberrans, Phytoseius finitimus, Typhlodromus pyri eggs and motile forms increased after a phase of large pollen availability. Hop pollen promoted K. aberrans population increases in vineyards. Pollen applications increased predatory mite egg and motile form densities and similar effects were obtained by reducing mowing frequency in vineyards.
CONCLUSION
Pollen availability positively affects the biology of four phytoseiid species, promoting stable predatory mite populations in vineyards. However, natural pollen availability and predatory mite abundance often decrease in summer, and pollen supply can mitigate this trend. A higher pollen availability could be guaranteed by inserting hedges comprising species having scalar bloom, reducing mowing of inter-row groundcover and spraying pollen. The presence of flowering plants surrounding vineyards and in their inter-rows should be considered as a relevant factor to enhance the success of biocontrol tactics against phytophagous mites in viticulture
Biological control of mites in European vineyards and the impact of natural vegetation
In vineyards, generalist phytoseiids are important in keeping phytophagous mites at economically acceptable levels. Among these predators, Typhlodromus pyri and Kampimodromus aberrans have proven to be most effective, because they increase in numbers in response to mite pests and alternative prey/food, they persist under conditions of prey scarcity, and they can tolerate several fungicides and insecticides. Natural colonization of commercial vineyards by phytoseiids may take several years. Therefore, strains showing field resistance to certain insecticides (e.g., organophosphates) and fungicides (e.g., mancozeb) are of practical interest. Here we report results obtained with releasing T. pyri and K. aberrans strains with different pesticide histories, with emphasis on factors affecting their persistence, i.e., alternative food availability (pollen or downy mildew), leaf morphology, and selective pesticides. Natural vegetation surrounding vineyards may impact the densities of phytoseiids in neighbouring crops. For example, phytoseiid densities on plants surrounding vineyards under IPM in Southern France (Languedoc-Roussillon) were correlated with leaf structures, and K. aberrans density appeared positively affected by high trichome densities and presence of domatia. Also pollen density was significantly correlated with trichome density and domatia (hair tufts). Predatory mites disperse mainly by air currents and hence their dispersion depends on wind intensity and direction. Crop colonization potential (speed, intensity, uniformity) was directly associated with phytoseiid densities and the proximity of natural vegetation. A deep, dense, and tall woody area with suitable host plants constitutes the stablest source of phytoseiids. Natural colonization of vineyards by phytoseiid mites has great potential and it may well be promoted by careful management
Investigations on the grape leafhopper Erasmoneura vulnerata in north-eastern Italy
The leafhopper Erasmoneura vulnerata (Fitch) (Hemiptera: Cicadellidae) is native of Northern and Central America where it occurs on wild and cultivated grapes as well as on a number of secondary hosts. This species was recorded for the first time in Europe (Italy, Veneto region) in 2004. Since then it has spread over Northern Italy and Slovenia. Studies on the biology of E. vulnerata in America are limited and thus its phenology was investigated on Vitis labrusca L. and Vitis vinifera L. plants under field and semi-field conditions. These observations suggest that E. vulnerata can complete 2⁻3 generations per year. The development of E. vulnerata from first instar nymphs to adults was studied under controlled conditions (about 23 °C). Developmental times lasted from 16.1 days in July⁻August to 19.5 days in September, and this variability was probably due to grape cultivar and plant susceptibility. Data were consistent with the number of generations previously reported. Erasmoneura vulnerata was more abundant on vines close to overwintering sites than on those located 100⁻250 m from these sites and contiguous to commercial vineyards
An update of the Worldwide Integrated Assessment (WIA) on systemic insecticides. Part 3:Â alternatives to systemic insecticides
International audience; Over-reliance on pesticides for pest control is inflicting serious damage to the environmental services that underpin agricultural productivity. The widespread use of systemic insecticides, neonicotinoids, and the phenylpyrazole fipronil in particular is assessed here in terms of their actual use in pest management, effects on crop yields, and the development of pest resistance to these compounds in many crops after two decades of usage. Resistance can only be overcome in the longterm by implementing methods that are not exclusively based on synthetic pesticides. A diverse range of pest management tactics is already available, all of which can achieve efficient pest control below the economic injury level while maintaining the productivity of the crops. A novel insurance method against crop failure is shown here as an example of alternative methods that can protect farmer's crops and their livelihoods without having to use insecticides. Finally, some concluding remarks about the need for a new framework for a truly sustainable agriculture that relies mainly on natural ecosystem services instead of chemicals are included; this reinforcing the previous WIA conclusions (van der Sluijs et al. Environ Sci Pollut Res 22:148-154, 2015)
Scaphoideus titanus forecasting and management: quo vadis?
Scaphoideus titanus Ball (Hemiptera: Cicadellidae) is a major pest for European viticulture due to its high
efficiency in the transmission of one of the most destructive pathogens for grapevine, namely flavescence dorée phytoplasmas. Although it plays a major role in spreading this disease, S. titanus is part of a complex epidemiological cycle involving several alternative vectors with variable relevance for phytoplasma spread. Here we provide an updated review on
S. titanus monitoring and modelling, as well as the available tools for management of this pest and for limiting phytoplasma
transmission and, thus, also spread. Insecticide-based control is examined; additional emphasis is placed on innovative and
low-impact control approaches, such as vibrational mating disruption, biocontrol, and methods to reduce vector competence. We also discuss the main emerging challenges to the implementation of effective and sustainable control programs
against S. titanus
Scaphoideus titanus up-to-the-minute: biology, ecology, and role as a vector
Native to the Nearctic region, Scaphoideus titanus Ball (Hemiptera: Cicadellidae) has become a major threat for
grapevine production after being unintentionally introduced into Europe, where it became the main vector of flavescence
dorée phytoplasma, being mainly associated with the genus Vitis. Scaphoideus titanus is a highly efficient vector of the
most important phytoplasma affecting grapevine. For this reason, compulsory insecticide treatments have been introduced
against this pest in many European countries. Moreover, the continuous expansion of its geographical distribution makes
this leafhopper a serious threat for several non-European Countries. In this article, we review the current knowledge about
its taxonomy, morphology, biology, ecology, and its role as a vector. Finally, we point out the main challenges for research
aimed at reducing S. titanus and flavescence dorée expansion across Europe and avoiding spread of the disease outside the
Old World
Climate and landscape composition explain agronomic practices, pesticide use and grape yield in vineyards across Italy
Context
Worldwide, organic farming is being promoted as one of the main alternatives to intensive conventional farming. However, the benefits of organic agriculture are still controversial and need to be tested across wide environmental gradients.
Objective
Here, we carried out an observational study to test how agronomic practices, pest management, environmental impact and yield of conventional and organic vineyards changed along wide climatic and landscape gradients across Italy.
Methods
We used a block design with 38 pairs of conventional and organic vineyards across Italy.
Results and conclusions
Most agronomic practices did not differ between conventional and organic vineyards. By contrast, landscape composition and climate were strong predictors of management in both systems. First, increasing semi-natural areas around the vineyards reduced pesticide pressure and related environmental impacts, but was also associated with lower yield. Second, irrespective of the farming system, a warm and dry climate was associated with reduced fungicide pressure. Conventional farming had a yield gain of 40% in cold and wet climate compared to organic but the yield gap disappeared in the warmest regions.
Significance
In both farming systems, we observed a large variability in management practices that was mainly explained by climate and landscape composition. This large variability should be considered when evaluating the benefits and drawbacks of different farming systems under contrasting environmental contexts
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