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In the present review, we compiled and evaluated the available information supporting the assessment of population and community recovery after pesticide application. This information is crucial for the environmental risk assessment of pesticides. We reviewed more than 3900 manuscripts on those organism groups relevant or likely to become relevant for the risk assessment procedures in Europe, that is, aquatic invertebrates, algae, aquatic plants, fish, aquatic microbes, amphibians, as well as birds and mammals, non-target terrestrial arthropods including honeybees, non-arthropod invertebrates, terrestrial microbes, non-target terrestrial plants, nematodes, and reptiles. Finally, 106 aquatic and 76 terrestrial studies met our selection criteria and were evaluated in detail. We extracted the following general conclusions. (i) Internal recovery depends strongly on reproduction capacity. For aquatic invertebrates, recovery was generally observed within a maximum of five generation times. (ii) In cases where recovery occurred within one generation, migration from uncontaminated areas was identified as the main pathway for aquatic and terrestrial invertebrates, in particular, for insect species with the ability for aerial recolonization. (iii) Community composition in general did not recover within the study duration in the majority of cases. (iv) The ecological context, including factors such as food resources, habitat quality, and recolonization potential, is a crucial factor for recovery from pesticide effects. (v) Indirect effects acting through food chain processes, including predation and competition, are highly relevant for increasing the magnitude of effect and for prolonging recovery time. Based on our findings, we recommend defining realistic scenarios for risk assessment regarding exposure, taxa considered, environmental conditions, and ecological context. In addition to experimental studies, field monitoring was shown to yield valuable information to identify relevant taxa, long-term effects, and the conditions for recovery, and should therefore be considered to validate approaches of risk assessment. Likewise, ecological modelling was found to be a valuable tool for assessing recovery. Finally, both study design and interpretation of results still often suffer from missing ecological information or from neglect of the available knowledge. Hence, a more rigorous utilization of existing knowledge (e.g., from general disturbance ecology) and the generation of systematic ecological knowledge on the various factors influencing recovery are needed.

Biocontrol involves harnessing disease-suppressive microorganisms to improve plant health. Disease suppression by biocontrol agents is the sustained manifestation of interactions among the plant, the pathogen, the biocontrol agent, the microbial community on and around the plant, and the physical environment. Even in model laboratory systems, the study of biocontrol involves interactions among a minimum of three organisms. Therefore, despite its potential in agricultural applications, biocontrol is one of the most poorly understood areas of plant-microbe interactions. The complexity of these systems has influenced the acceptance of biocontrol as a means of controlling plant diseases in two ways. First, practical results with biocontrol have been variable. Thus, despite some stunning successes with biocontrol agents in agriculture, there remains a general skepticism born of past failures (Cook and Baker, 1983; Weller, 1988). Second, progress in understanding an entire system has been slow. Recently, however, substantial progress has been made in a number of biocontrol systems through the application of genetic and mathematical approaches that accommodate the complexity. Biocontrol of soilborne diseases is particularly complex because these diseases occur in the dynamic environment at the interface of root and soil known as the rhizosphere, which is defined as the region surrounding a root that is affected by it. The rhizosphere is typified by rapid change, intense microbial activity, and high populations of bacteria compared with non-rhizosphere soil. Plants release metabolically active cells from their roots and deposit as much as 20% of the carbon allocated to roots in the rhizosphere, suggesting a highly evolved relationship between the plant and rhizosphere microorganisms. The rhizosphere is subject to dramatic changes on a short temporal scale-rain events and daytime drought can result in fluctuations in salt concentration, pH, osmotic potential, water potential, and soil particle structure. Over longer temporal scales, the rhizosphere can change due to root growth, interactions with other soil biota, and weathering processes. It is the dynamic nature of the rhizosphere that makes it an interesting setting for the interactions that lead to disease and biocontrol of disease (Rovira, 1965, 1969, 1991; Hawes, 1991; Waisel et al., 1991). The complexity of the root-soil interface must be accommodated in the study of biocontrol, which must involve whole organisms and ultimately entire communities, if we are to understand the essential interactions in soil in the field. The challenge in elucidating mechanisms of biocontrol is in reducing the complexity to address tractable scientific questions. One of the most effective approaches toward the identification of critical variables in a complex system has been genetics. The study of mutants can be conducted in simplified laboratory systems or in the field, thus making accessible the examination of particular genetic changes and the associated biochemical characteristics in the real world. This review presents recent advances in our understanding of the biocontrol of root diseases. We emphasize research aimed at enhancing our understanding of the biology of the interactions that result in disease suppression. It is this understanding that will make possible the practical use of microorganisms in the management of plant disease in agroecosystems. Numerous recent reviews present comprehensively the variety of microbial biocontrol agents (Chet, 1987; Weller, 1988; Whipps and Lumsden, 1991; O'Sullivan and O'Gara, 1992; Cook, 1993; Goldman et al., 1994; Cook et al., 1995; Lumsden et al., 1995). In this discussion of current and future directions in biocontrol, our goal is to present key themes in the discipline, drawing on the bacteria Pseudomonas and Bacillus and the fungi Trichoderma and Gliocladium as examples representing a range of life strategies and mechanisms of disease suppression. We address the principles of interactions of the biocontrol agent with the pathogen, the host plant, and the microbial community, illustrating each principle with some well-studied examples of successful biocontrol agents (DBO).

The side effect of 10 insecticides, 5 fungicides and 5 herbicides on 24 different species of beneficial organisms was tested by members of the Working Group ‘Pesticides and Beneficial Organisms’ of the International Organization for Biological Control (IOBC), West Palaearctic Regional Section (WPRS). The tests were conducted by 32 members in 12 countries according to internationally approved guidelines.The microbial insecticides Bacillus thuringiensis var. kurstaki (Delfin), B. thuringiensis var. tenebrionis (Novodor) and Verticillium lecanii (Micro Germin), the fungicides cyproconazol (Alto), difenoconazol (Score), lecithin (Bioblatt Mehltau) and penconazol (Omnex), and the herbicides ethofumesat (Tramat), fluroxypyr (Starane), haloxyfop (Gallant), isoproturon (Arelon) and metamitron (Goltix) were harmless to nearly all the beneficial arthropods. The benzoylurea's teflubenzuron (Nomolt) and flufenoxuron (Cascade) affected predators such as anthocorids, earwigs, coccinellids and lacewings. The remaining preparations were more toxic and should therefore be further tested in semi-field and field experiments on relevant organisms. Most tested fungicides were toxic for the entomopathogenic fungi.

Genetic resistance in plants to root diseases is rare, and agriculture depends instead on practices such as crop rotation and soil fumigation to control these diseases. \"Induced suppression\" is a natural phenomenon whereby a soil due to microbiological changes converts from conducive to suppressive to a soilborne pathogen during prolonged monoculture of the susceptible host. Our studies have focused on the wheat root disease \"take-all,\" caused by the fungus Gaeumannomyces graminis var. tritici, and the role of bacteria in the wheat rhizosphere (rhizobacteria) in a well-documented induced suppression (take-all decline) that occurs in response to the disease and continued monoculture of wheat. The results summarized herein show that antibiotic production plays a significant role in both plant defense by and ecological competence of rhizobacteria. Production of phenazine and phloroglucinol antibiotics, as examples, account for most of the natural defense provided by fluorescent Pseudomonas strains isolated from among the diversity of rhizobacteria associated with take-all decline. There appear to be at least three levels of regulation of genes for antibiotic biosynthesis: environmental sensing, global regulation that ties antibiotic production to cellular metabolism, and regulatory loci linked to genes for pathway enzymes. Plant defense by rhizobacteria producing antibiotics on roots and as cohabitants with pathogens in infected tissues is analogous to defense by the plant's production of phytoalexins, even to the extent that an enzyme of the same chalcone/stilbene synthase family used to produce phytoalexins is used to produce 2,4-diacetylphloroglucinol. The defense strategy favored by selection pressure imposed on plants by soilborne pathogens may well be the ability of plants to support and respond to rhizosphere microorganisms antagonistic to these pathogens.

Description du sujet. Les effets des doses recommandées de cinq produits à usage fréquent dans les fraisiers de la région du Loukkos (Maroc) ont été étudiés chez l’acarien tisserand Tetranychus urticae et sur son acarien prédateur Phytoseiulus persimilis. Des études de laboratoire ont permis de tester la toxicité de contact d’un acaricide appartenant à la famille des avermectines (abamectine), de deux insecticides-acaricides de la famille des pyréthrinoïdes (bifenthrine et lambda-cyhalothrine) et deux fongicides : le mancozèbe appartenant à la famille chimique des dithiocarbamates et l’hexaconazole de la famille des triazoles. Objectifs. L’objectif de la présente étude est de tester, dans les conditions de laboratoire, l’effet de cinq pesticides sur l’acarien à deux points T. urticae et son acarien prédateur P. persimilis. Ces cinq pesticides ont été les plus utilisés durant les deux dernières années dans le site expérimental choisi. Méthode. Les tests biologiques sont réalisés avec des populations originaires de trois groupes de parcelles ayant des passés phytopharmaceutiques différents. Le premier groupe a été fréquemment traité avec les cinq pesticides testés et ce, durant une période de deux ans. Le second groupe a reçu le même traitement mais avec une fréquence moyenne. Le troisième groupe a été traité une seule fois avec les pesticides testés. Résultats. Nos résultats indiquent que les pesticides testés permettent un contrôle efficace de T. urticae mais sont, pour la plupart, peu compatibles avec son acarien prédateur P. persimilis, si ce dernier n’est pas habituellement en contact avec ces produits. En revanche, dans les parcelles où les pesticides ont fréquemment été utilisés, la sensibilité de P. persimilis à ces produits est significativement réduite. Conclusions. Si les pesticides testés peuvent être introduits dans les programmes de lutte intégrée contre les ravageurs dans les parcelles où ils ont été utilisés depuis longtemps et où P. persimilis est présent, leur utilisation doit être minimisée dans les parcelles où ils ont été rarement ou jamais appliqués. Influence of previous pesticide use on Tetranychus urticae and Phytoseiulus persimilis (Acari: Tetranychidae, Phytoseiidae) from strawberry crops in the north of MoroccoDescription of the subject. Effects of recommended doses of five common pesticides in the strawberries of Loukkos area (Morocco) were tested on the two-spotted spider mite Tetranychus urticae and its predatory mite Phytoseiulus persimilis. Laboratory study assessed the contact toxicity of one avermectin miticide (abamectin), two pyrethrinoid insecticide-acaricides (bifenthrin and lambda-cyalothrin), and two fungicides: firstly, mancozeb, which belongs to the dithiocarbamates family of chemicals and secondly, hexaconazole, of the triazole family.Objectives. The aim of the present study was to test in laboratory conditions the effect of five pesticides on the two-spotted spider mite, T. urticae and its predatory mite, P. persimilis. The five pesticides tested were those most frequently applied for at least two years on strawberries at the experimental site.Method. Bioassays were performed with populations of mites originating from different plots with various crop protection backgrounds. The first group of plots had been repeatedly treated with the five tested pesticides during a two-year period, the second group had been moderately treated, and the third had been treated once with the tested pesticides. Results. Our results showed that the tested pesticides provided effective control of T. urticae but that they were not compatible with use on the predatory mite P. persimilis, as these particular mites did not usually come into contact with these products. On the other hand, in plots where pesticides had been used for a long time, the susceptibility of P. persimilis populations to these products was significantly reduced.Conclusions. If the tested pesticides are to be considered for integrated pest control programs in plots where they have been used for a long time and where P. persimilis is present, their use should be minimized in plots where they have never or rarely been applied.

In the present study, brown rice was steeped in 20 % wettable powder fludioxonil for 24 h, subsequently germinated, and transplanted in paddy fields. The harvested rice was tested at 156 days to detect residue levels using gas chromatography-nitrogen phosphorus detector. Validation was carried out to assess the following parameters: linearity, limit of detection and limit of quantitation (LOQ), recovery, and storage stability. Using matrix-matched calibrations, the determination coefficients were >0.999 in both matrices. Mean recoveries were 73.5–101.0 % with relative standard deviations <10 % in both matrices. The LOQ (0.006 mg/kg) was lower than the maximum residue limit (MRL = 0.02 mg/kg) set by the Ministry of Food and Drug Safety, Republic of Korea. The developed method was applied successfully, and no residues were detected in field-incurred rice and/or rice straw samples.

Introduction. Anthracnose disease causes severe economic losses in strawberry (Fragaria × ananassa) production. Plant response to the pathogen attack is closely linked to its content and composition of polyphenols. In order to reduce the damage caused by pathogens, organic and inorganic fungicides are applied. The aim was to determine the influence of selected fungicides on various metabolites in strawberry fruit. Materials and methods. The efficiency of potassium bicarbonate (PBC) and acetic acid (AA) was compared with the control and a fungicide treatment in the strawberry cv. Elsanta. To examine the possible effects of these fungicides, artificial inoculation was performed in all treatments except for the control. The percentage of infected fruits and the content of selected primary and secondary metabolites in non-infected and infected fruits were determined. Results and discussion. Both analyzed inorganic fungicides proved effective against anthracnose. AA treated fruits were the least infected (only 4%), followed by PBC, fungicide and control. The highest percentage (9.26%) of infected fruits was determined following artificial infection treatment. Total sugar content decreased for 32% in infected control and AA treated fruits. PBC treatment exhibited a positive effect on the organic acid content in comparison with other treatments. The content of phenolic compounds was higher in PBC treated fruits and did not change significantly after infection. Infection increased the total flavonol content of the fruit. Conclusion. The use of PBC and AA potentially present a prospective protection in the strawberry orchards especially for controlling anthracnose in organic fruit crops. Introduction. L’anthracnose provoque des pertes économiques importantes en production de fraises (Fragaria × ananassa). La réponse de la plante à l’attaque des agents pathogènes est étroitement liée à sa teneur et à sa composition en polyphénols. Pour réduire les dommages causés par les agents pathogènes, des fongicides organiques et inorganiques sont appliqués. Nous avons cherché à déterminer l’influence de ces fongicides sur certains métabolites présents dans la fraise. Matériel et méthodes. L’efficacité du bicarbonate de potassium (PBC) et de l’acide acétique (AA) a été comparée à celle du contrôle et d’un traitement fongicide sur le cultivar Elsanta. En vue d’examiner les effets potentiels de ces fongicides, une inoculation artificielle a été réalisée pour tous les traitements sauf pour le contrôle. Le pourcentage de fruits infectés, ainsi que le contenu en certains métabolites primaires et secondaires contenus dans les fruits non infectés et infectés ont été déterminés. Résultats et discussion. Les deux fongicides inorganiques étudiés se sont révélés efficaces contre l’anthracnose. Les fruits traités à l’AA ont été les moins infectés (seulement 4 %), suivis par ceux traités au PBC, au fongicide et ceux du contrôle. Le pourcentage le plus élevé (9,26 %) de fruits infectés a été obtenu suite à une inoculation artificielle. La teneur en sucres totaux a diminué de 32 % dans les fruits du contrôle infecté et ceux traités à l’AA. Le traitement au PBC a montré un effet positif sur la teneur en acides organiques en comparaison avec les autres traitements. La teneur en composés phénoliques a été plus élevée dans les fruits traités au PBC et n’a pas changé de manière significative après infection. L’infection a augmenté la teneur des fruits en flavonols totaux. Conclusion. L’utilisation du PBC et de l’AA présente une protection potentielle des vergers de fraisiers, en particulier dans la perspective du contrôle de l’anthracnose en culture biologique.

Introduction. L’utilisation excessive de fongicides chimiques continue à pousser la recherche vers des alternatives pour la protection des cultures qui soient respectueuses de l’environnement, mais aussi novatrices. Littérature. Les champignons produisent divers mélanges de composés en phase gazeuse, appelés Composés Organiques Volatils (COVs). Ils sont capables de se diffuser dans le sol et dans l’atmosphère et d’inhiber les activités des pathogènes fongiques. Dans cette section, nous résumerons les connaissances récentes sur le potentiel inhibiteur des Composés Organiques Volatils contre les champignons pathogènes en mettant l’accent sur l’effet des COVs fongiques. Dans la pratique, nous y dévoilerons les premières recherches déchiffrant leur mode d’action et les éventuels effets phytotoxiques non spécifiques sur le microbiome environnemental ainsi que sur les plantes. Conclusions. Cet article porte sur les nouvelles techniques utilisées par les chercheurs qui mettent l’accent sur la mycofumigation afin d’optimiser la formulation d’une nouvelle génération de biofongicides. Ainsi, se dessine un nouvel horizon en matière de lutte biologique contre les maladies des cultures. Efficacy of fungi Volatile Organic Compounds. A review Introduction. Excessive use of chemical fungicides continues to drive research towards environmentally friendly and innovative alternatives for crop protection. Literature. Fungi produce various mixtures of compounds in the gas phase, called Volatile Organic Compounds (VOCs). They are able to diffuse into the soil and into the atmosphere and inhibit the activities of fungal pathogens. In this section, we will summarize recent knowledge on the inhibitory potential of Volatile Organic Compounds against pathogenic fungi with a focus on the effect of fungal VOCs. In practice, we will unveil initial research revealing their mode of action and any non-specific phytotoxic effects on the environmental microbiome and on plants. Conclusions. This article discusses new techniques used by researchers that focus on mycofumigation to optimize the formulation of a new generation of biofungicides. Thus, a new horizon is emerging for biological control of crop diseases.

A study was conducted to investigate the possibility of involvement of chitinase and β-1,3-glucanase of an antagonistic fluorescent Pseudomonas in growth suppression of phytopathogenic fungi, Phytophthora capsici and Rhizoctonia solani . Fluorescent Pseudomonas isolates GRC 3 and GRC 4 were screened for their antifungal potential against phytopathogenic fungi by using dual culture technique both on solid and liquid media. The percent inhibition was calculated. Various parameters were monitored for optimization of enzyme activities by fluorescent Pseudomonas GRC 3 . The involvement of chitinases, β-1,3-glucanases, and antifungal metabolites of nonenzymatic nature was correlated with the inhibition of P. capsici and R. solani. The results provide evidence for antibiosis as a mechanism for antagonism. The study also confirms that multiple mechanisms are involved in suppressing phytopathogens as evidenced by the involvement of chitinase and β-1,3-glucanase in inhibition of R. solani but not P. capsici by isolate GRC 3 .

Wheat head blight pathogens Fusarium graminearum and Microdochium nivale have distinct sensitivities to strobilurin fungicides, which inhibit activity of complex III in the mitochondrial electron transport chain. When mycelia were cultured in medium with the strobilurin fungicide azoxystrobin (AZ), F. graminearum increased its oxygen-consumption, but M. nivale, which is more sensitive than Fusarium species to strobilurins, did not. There was no increase in oxygen consumption in F. graminearum by the treatment with AZ and alternative oxidase (AOX) inhibitor n-propyl gallate. AZ enhanced the generation of intracellular H2O2 in both fungi. Activities of antioxidant enzymes in M. nivale were consistently higher than in F. graminearum. Quantification of AOX transcripts by real-time PCR indicated that transcription of AOX in F. graminearum and M. nivale was induced by AZ, suggesting that AOX activities in both fungi are regulated at the transcriptional level. AOX transcription in F. graminearum was rapidly induced by AZ and reached a maximum by 60 min after treatment. On the contrary, induction in M. nivale was low and slow. These results suggest that differential ability of F. graminearum and M. nivale to activate AOX transcription is involved in the difference in their sensitivity to AZ.