Rob Moerkens1,2, Els Berckmoes3, Veerle Van Damme4,5, Nelia Ortega-Parra6, Inge Hanssen6, Martine Wuytack3, Lieve Wittemans3, Hans Casteels4, Luc Tirry5, Patrick De Clercq5, Raf De Vis3. 1. Tomato Research, Research Centre Hoogstraten, Hoogstraten, Belgium. 2. Evolutionary Ecology Group, University of Antwerp, Belgium. 3. Research Station for Vegetable Production, Sint-Katelijne-Waver, Belgium. 4. Institute for Agricultural and Fisheries Research (ILVO), Merelbeke, Belgium. 5. Laboratory of Agrozoology, Department of Crop Protection, Faculty of Bioscience Engineering, Ghent University, Gent, Belgium. 6. Scientia Terrae Research Institute, Sint-Katelijne-Waver, Belgium.
Abstract
BACKGROUND: The zoophytophagous predator Macrolophus pygmaeus Rambur (Hemiptera: Miridae) is a successful biocontrol agent against several pest species in protected tomato crops. This predator is considered to be harmless for the crop. However, in recent years, Heteroptera feeding punctures on tomato fruit in Belgian and Dutch greenhouses have been misinterpreted as Pepino mosaic virus (PepMV) symptoms. In this study, three hypotheses were tested: (1) M. pygmaeus causes fruit damage that increases with population density and surpasses economic thresholds; (2) the presence of prey or alternative prey reduces the damage; (3) an infection of the tomato plants by PepMV triggers or aggravates M. pygmaeus fruit damage. RESULTS: At increasing M. pygmaeus densities, the severity of fruit damage increased from a few dimples towards yellowish discoloration and deformed fruits. A correlation with an infection with PepMV was found. The severity of the symptoms was independent of the presence of prey. A minimum economic density threshold was estimated at 0.32 M. pygmaeus per leaf. CONCLUSION: M. pygmaeus can cause economic damage to tomato fruits at densities common in practice. An infection of the plants with PepMV enhances fruit symptoms significantly. Interacting plant defence responses are most likely the key to explaining this, although confirmation is required.
BACKGROUND: The zoophytophagous predator Macrolophus pygmaeus Rambur (Hemiptera: Miridae) is a successful biocontrol agent against several pest species in protected tomato crops. This predator is considered to be harmless for the crop. However, in recent years, Heteroptera feeding punctures on tomato fruit in Belgian and Dutch greenhouses have been misinterpreted as Pepino mosaic virus (PepMV) symptoms. In this study, three hypotheses were tested: (1) M. pygmaeus causes fruit damage that increases with population density and surpasses economic thresholds; (2) the presence of prey or alternative prey reduces the damage; (3) an infection of the tomato plants by PepMV triggers or aggravates M. pygmaeus fruit damage. RESULTS: At increasing M. pygmaeus densities, the severity of fruit damage increased from a few dimples towards yellowish discoloration and deformed fruits. A correlation with an infection with PepMV was found. The severity of the symptoms was independent of the presence of prey. A minimum economic density threshold was estimated at 0.32 M. pygmaeus per leaf. CONCLUSION:M. pygmaeus can cause economic damage to tomato fruits at densities common in practice. An infection of the plants with PepMV enhances fruit symptoms significantly. Interacting plant defence responses are most likely the key to explaining this, although confirmation is required.
Authors: Maria L Pappas; Colette Broekgaarden; George D Broufas; Merijn R Kant; Gerben J Messelink; Anke Steppuhn; Felix Wäckers; Nicole M van Dam Journal: Pest Manag Sci Date: 2017-06-08 Impact factor: 4.845