Articles
FUNCTIONAL BIODIVERSITY IN SOUTHERN FRANCE: A METHOD TO ENHANCE PREDATORY MIRID BUG POPULATIONS
Article number
915_20
Pages
165 – 170
Language
English
Abstract
Functional biodiversity inter alia consists of establishing specific host plant species which increase the occurrence of beneficial insects by providing shelter and alternative prey near agricultural crops.
This technique, also called biological control by habitat management, was adapted in Southern France to control spider mites (Tetranychus urticae) and white flies (Trialeurodes vaporariorum and Bemisia tabaci) using two predatory mirid bugs (Macrolophus melanotoma (=caliginosus) and Dicyphus errans). Trials began in 2007 with the selection of suitable host plants for these two mirids.
Twenty-two species of host plants were sown in strips between greenhouses at the GRAB experimental farm (Avignon Provence), and germination rates and competition with weeds were evaluated.
Extensive insect sampling from these host-plants was conducted.
The ratio of the number of predators: number of phytophagous arthropods was calculated and the number of predatory mirid bugs recorded. Dittrichia viscosa and Calendula officinalis appeared to be the most promising host plant species due to their rusticity, their high ratio of predators:phytophages and their ability to shelter M. caliginosus and D. errans. These two species were sown in 2009 on three different commercial farms around Avignon.
Mixtures of seeds of the two species were compared to pure plots of D. viscosa and C. officinalis.
Dittrichia viscosa which had poor late germination was out-competed by C. officinalis in the mixed plantings.
Sowing at 3 g m-2 for D. viscosa and 2.5 g m-2 for C. officinalis gave the best results in terms of ground cover.
As noted in 2007 and 2008 at the GRAB experimental farm, D. viscosa and C. officinalis sheltered many more predatory bugs than the control (spontaneous flora) did.
This technique, also called biological control by habitat management, was adapted in Southern France to control spider mites (Tetranychus urticae) and white flies (Trialeurodes vaporariorum and Bemisia tabaci) using two predatory mirid bugs (Macrolophus melanotoma (=caliginosus) and Dicyphus errans). Trials began in 2007 with the selection of suitable host plants for these two mirids.
Twenty-two species of host plants were sown in strips between greenhouses at the GRAB experimental farm (Avignon Provence), and germination rates and competition with weeds were evaluated.
Extensive insect sampling from these host-plants was conducted.
The ratio of the number of predators: number of phytophagous arthropods was calculated and the number of predatory mirid bugs recorded. Dittrichia viscosa and Calendula officinalis appeared to be the most promising host plant species due to their rusticity, their high ratio of predators:phytophages and their ability to shelter M. caliginosus and D. errans. These two species were sown in 2009 on three different commercial farms around Avignon.
Mixtures of seeds of the two species were compared to pure plots of D. viscosa and C. officinalis.
Dittrichia viscosa which had poor late germination was out-competed by C. officinalis in the mixed plantings.
Sowing at 3 g m-2 for D. viscosa and 2.5 g m-2 for C. officinalis gave the best results in terms of ground cover.
As noted in 2007 and 2008 at the GRAB experimental farm, D. viscosa and C. officinalis sheltered many more predatory bugs than the control (spontaneous flora) did.
Authors
J. Lambion
Keywords
biological control, Dittrichia, Calendula, Dicyphus, habitat management, host plant, Macrolophus, organic horticulture
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