Apparent competition between major pests reduces pest population densities on tomato crop, but not yield loss

Jaworski Coline C., Chailleux Anaïs, Bearez Philippe, Desneux Nicolas. 2015. Apparent competition between major pests reduces pest population densities on tomato crop, but not yield loss. Journal of Pest Science, 88 (4) : 793-803.

Quartile : Q1, Sujet : ENTOMOLOGY

Résumé : Increased pest control by generalist predators has been successfully achieved in several cases by promoting apparent competition, which is the reciprocal negative interactions between prey mediated by their shared predator. However, the presence of alternative prey does not always result in an improved control of the target pest species, due to the complexity and specificity of biotic interactions. To increase the effectiveness of IPM programs, a fine understanding of the interactions among co-occurring pest species and their biocontrol agents is necessary. We tested the occurrence of apparent competition between the major tomato pests Tuta absoluta and Bemisia tabaci when preyed on by a generalist mirid bug Macrolophus pygmaeus, by monitoring pest and predator population dynamics in a greenhouse experiment. We also measured the cascading effect of the shared predator on plant and fruit damage due to pests. We observed higher predator population growth and reduced population densities of both prey in treatments with two prey, as compared to treatments with one prey, showing that apparent competition occurred. Plant and fruit damage caused by B. tabaci was reduced in the presence of T. absoluta, but damage due to T. absoluta, which accounted for the major part, was not reduced in the presence of B. tabaci, resulting in similar levels of total damage when pests co-occurred. This study demonstrates that, even if promoting apparent competition leads to actual reduction in pest densities, yield loss may not be reduced when this strategy is applied to major pests such as T. absoluta.

Mots-clés Agrovoc : Solanum lycopersicum, ravageur des plantes, interactions biologiques, Bemisia tabaci, Macrolophus, agroécosystème, compétition biologique, dynamique des populations, perte de récolte, évaluation de l'impact, Tuta absoluta

Mots-clés complémentaires : Macrolophus pygmaeus

Classification Agris : H10 - Ravageurs des plantes
L20 - Écologie animale

Champ stratégique Cirad : Axe 4 (2014-2018) - Santé des animaux et des plantes

Auteurs et affiliations

• Jaworski Coline C., Université Toulouse III Paul Sabatier (FRA)
• Chailleux Anaïs, CIRAD-PERSYST-UPR HortSys (FRA)
• Bearez Philippe, INRA (FRA)
• Desneux Nicolas, INRA (FRA)

Source : Cirad-Agritrop (https://agritrop.cirad.fr/577994/)

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