1,721,069 research outputs found
Diversification practices: their effect on pest regulation and production
No full textThe interest to shift pest management strategies from the intensive use of agrochemicals to more sustainable and ecologically friendly practices has increased in recent years. One alternative to conventional farming systems is the implementation of diversification practices that increase diversity in- and around- the field to increase the incidence of natural enemies, reduce pest pressure and enhance crop production. In this review we illustrate the theoretical framework on which diversification practices are based and contrast it with the empirical evidence. The detailed review of 62 original studies published in the last ten years, shows that diversification practices (a) enhance natural enemies in 52%, (b) reduce pest pressure in 53% and (c) increase yield in only 32% of the cases where this was examined. We discuss these results On the basis of the reviewed Studies providing key elements that should he taken into account to design diversification practices that can be implemented as competitive pest management strategies that cover the farmers' needs, reducing the intensive use of agrochemicals.German Science Foundatio
Diversification practices: their effect on pest regulation and production
No full textThe interest to shift pest management strategies from the intensive use of agrochemicals to more sustainable and ecologically friendly practices has increased in recent years. One alternative to conventional farming systems is the implementation of diversification practices that increase diversity in- and around- the field to increase the incidence of natural enemies, reduce pest pressure and enhance crop production. In this review we illustrate the theoretical framework on which diversification practices are based and contrast it with the empirical evidence. The detailed review of 62 original studies published in the last ten years, shows that diversification practices (a) enhance natural enemies in 52%, (b) reduce pest pressure in 53% and (c) increase yield in only 32% of the cases where this was examined. We discuss these results On the basis of the reviewed Studies providing key elements that should he taken into account to design diversification practices that can be implemented as competitive pest management strategies that cover the farmers' needs, reducing the intensive use of agrochemicals.German Science Foundatio
Herbivore-induced changes in fruit-frugivore interactions
No full text1. Herbivore attack can induce dramatic changes in plant chemical defences. These responses protect plants against future herbivory, but can also have important physiological and ecological costs. Ecological costs of defence have received recent theoretical attention; however, many proposed costs have not yet been demonstrated empirically. In particular, field data are lacking as to whether induced responses in leaves can lead to correlated changes in fruit palatability that reduce fruit removal by mutualist seed dispersers. 2. Using the tropical shrub, Hamelia patens (Rubiaceae), we examined changes in fruit removal, palatability and maturation time following various treatments to the subtending leaves, including herbivory, mechanical damage and/or application of methyl jasmonate (MeJA). 3. Fewer fruits were removed from herbivory- and MeJA-treated branches than from controls, and results from three bioassays with ants and fungi suggested that this response was mediated by changes in fruit palatability. In addition, fruits from MeJA-treated branches matured more quickly than those from control branches. 4. Synthesis. Taken together, our results provide novel evidence that induced responses to herbivory can affect fruit-frugivore interactions through two mechanisms: changes in fruit palatability and changes in fruit development time. This highlights the importance of physiological linkages between leaf and fruit traits in determining the overall costs of plant defence and the fitness outcomes of multispecies interactions.Emily P. Foster Memorial Fellowshi
Effects of below- and above-ground herbivores on plant growth, flower visitation and seed set
No full textBelowground effects of organic and conventional farming on aboveground plant–herbivore and plant–pathogen interactions
No full textFloral trait expression and plant fitness in response to below- and aboveground plant–animal interactions
No full textEffects of decomposers and herbivores on plant performance and aboveground plant-insect interactions
No full textSynergistic effects of repellents and attractants in potato tuber moth control
No full textPest management strategies aimed at reducing pesticide input often rely on behaviour-modifying stimuli to manipulate the distribution and abundance of pests and/or beneficial insects. However, the combined effect of more than one stimulus has rarely been tested. Here we show that the combination of two stimuli has a synergistic effect that controls herbivore damage and increases potato yield, despite the fact that each stimulus alone has no effect. A main potato pest in Colombia is the Guatemalan potato moth (Tecia solanivora) whose larvae specialize on potato tubers. To control this pest we tested the oviposition interference (repellence) of eight aromatic plants and the oviposition stimuli (attractiveness) of eight potato varieties. In the field we tested the effectiveness of the single and combined use of repellent and attractive stimuli on herbivore damage and tuber production of potato plants and compared the efficacy of these treatments to conventional management systems that employed insecticides. Although there was no effect of the attractive and repellent stimuli in the field when used alone, the combined use reduced the number of damaged tubers and increased the weight of undamaged tubers relative to the untreated plots, thus demonstrating a synergistic effect. Productivity in the conventionally treated plots was similar to plots treated with the combined stimuli. We demonstrate that the simultaneous use of garlic-pepper extracts and intercropping with S. tuberosum cv Roja Narino are an effective strategy for the management of T solanivora. This strategy maintains the productivity attained with conventional management practices, but without the health, environmental and ecological costs associated with the use of insecticides. (C) 2009 Gesellschaft fur Okologie. Published by Elsevier Gmbh. All rights reserved.German Research Foundation (DFG) [PO 1215_2.1, PO 1215_3.1
Herbivory-mediated pollinator limitation: negative impacts of induced volatiles on plant-pollinator interactions
No full textAlthough induced plant responses to herbivory are well studied as mechanisms of resistance, how induction shapes community interactions and ultimately plant fitness is still relatively unknown. Using a wild tomato, Solanum peruvianum, native to the Peruvian Andes, we evaluated the disruption of pollination as a potential ecological cost of induced responses. More specifically, we tested the hypothesis that metabolic changes in herbivore-attacked plants, such as the herbivore-induced emission of volatile organic compounds (VOCs), alter pollinator behavior and consequentially affect plant fitness. We conducted a series of manipulative field experiments to evaluate the role of herbivore-induced vegetative and floral VOC emissions as mechanisms by which herbivory affects pollinator behavior. In field surveys and bioassays in the plants' native habitat, we found that real and simulated herbivory (methyl jasmonate application) reduced attractiveness of S. peruvianum flowers to their native pollinators. We show that reduced pollinator preference, not resource limitation due to leaf tissue removal, resulted in reduced seed set. Solitary bee pollinators use floral plant volatiles, emitted in response to herbivory or methyl jasmonate treatment, as cues to avoid inflorescences on damaged plants. This herbivory-induced pollinator limitation can be viewed as a general cost of induced plant responses as well as a specific cost of herbivory-induced volatile emission
The enemy as ally: herbivore-induced increase in crop yield
No full textThere is increasing global concern over the risk of food shortage and instability, and a concomitant demand for an increase in food production. However, the continuing expansion of agricultural areas threatens natural habitats as well as human and ecosystem health. One option for increasing food production is to maximize yields from existing farmland. Here we demonstrate that larval feeding by the Guatemalan potato moth (Tecia solanivora), considered one of the most economically important potato pests in Latin America, leads to a dramatic increase in potato tuber production. Field-grown potato plants (Solanum tuberosum) in the Colombian Andes attacked by low numbers of potato moth larvae produce a 2.5-fold higher marketable potato yield than undamaged plants. Greenhouse experiments demonstrate that this effect is induced by larval regurgitant, rather than by mechanical tissue damage. Our results indicate that compounds from the foregut of T. solanivora are necessary and sufficient to induce an increased yield in potato. Our study suggests that using (1) herbivore-derived chemical cues and (2) induced compensatory plant responses to herbivory can provide viable new tools to increase per area crop productivity.German Research Foundation (DFG) [PO 1215_2.1, PO 1215_3.1
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