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INRA - 201604 Broad bean weevil
INRA CENTRES VERSAILLES-GRIGNON
INRA Centres > VersaillesGrignon > All the news > 201604 Broad bean weevil
Broad bean weevil: an example of a chemical signal emitted by a plant to serve as a biological control During behavioural and physiological studies of the broad bean weevil, Bruchus rufimanus, INRA scientists in VersaillesGrignon have identified two olfactory mixtures that could be used to ensure the biological control of this pest insect.
en français PUBLISHED ON 04/07/2016
UPDATED ON 09/06/2016
KEYWORDS: LEGUME BIOLOGICAL CONTROL INSECT PULSES BROAD BEAN WEEVIL
Bruchus rufimanus, more commonly known as broad bean weevil, is an insect that is specific to this plant, developing inside its seeds. The presence of weevils in grains means they are unfit for sale, reduces seed germination rates and constitutes a risk of crop reinfestation. For this reason, control of this pest insect is essential to ensure compliance with the quality criteria demanded by the market. At present, chemical controls have demonstrated their limitations, while good practices concerning treatment during flowering to protect bees, and more generally the global context of reducing pesticide use, have called their use into question. Proposing biological control solutions that are compatible with the sustainability of broad bean production thus constitutes a major challenge that has been the particular focus of INRA scientists in VersaillesGrignon.
Two olfactory mixtures of plant origin... As a result of behavioural and physiological studies, the scientists were able to show that B. rufimanus recognises broad beans from chemical signals emitted by the plant during its flowering and fruiting (pod) stages. They also demonstrated that the ability of a female insect to analyse volatile substances present in her environment is linked to her physiology and that of the plant: when the plant is at the flowering stage, the insect focuses on feeding, eating the pollen and flower petals while its ovaries are little developed; when the plant reaches the pod stage, the insect focuses on reproduction, laying its eggs on the pods when its mature ovaries are ready.
http://www.versailles-grignon.inra.fr/en/All-the-news/201604-Broad-bean-weevil
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1/23/2017
INRA - 201604 Broad bean weevil
By combining information linked to the perception and identification of these compounds thanks to gas chromatography coupled with mass spectrometry the scientists were able to select two original mixtures whose components were satisfactorily perceived by the insects as being characteristic of the flowering and pod stages. The degree of attractiveness of the two formulations was verified during two years of experimentation in the field.
...that could be used for the biological control of broad bean weevil These chemical ecological studies of an insect/cultivated plant pairing have been able to identify and formulate two mixtures, the first attractive to fertilised females (Pod attractant) and the second to males and females before laying (Flower attractant). These mixtures offer interesting perspectives regarding the control of broad bean weevil in the context of biological control techniques, which could be based on olfactory attraction or disruption. In the longer term, this knowledge is likely to interest plant geneticists who, using classic selection or by acting on the expression of a biosynthesis gene for volatile organic compounds, might be able to produce plants that are resistant to broad bean weevil. These studies and their results have given rise to a patent Reference: DIRV150005 RS B.FREROT; Ref number: BFF 15P0106; Reminder Extension FR 15 54037.
Contact(s) Scientific contact(s): Brigitte Frérot, Institute of Ecology and Environmental Sciences of Paris (Univ. Pierre et Marie Curie, CNRS, INRA, IRD, Univ. Paris Diderot, Univ. Paris Est Créteil Val de Marne) Associated Division(s): Plant Health and Environment
THE BROAD BEAN WEEVIL Bruxus rufimanus is a small beetle that is specific to broad beans and is commonly called broad bean weevil. The weevil only produces one generation each year. It develops in crops by eating the beans, and can be found in stored grain. In the spring, the adults leave their hibernation sites to colonise the crops in flower. The adult lays its eggs on the developing pods. After hatching, the larva penetrates the pod and then the grain, where it develops to produce an adult. This will escape by boring a round hole in order to find shelter in woodland or under tree bark. The control of broad bean weevil populations is essential to ensuring compliance with the quality criteria demanded by the market: the rate of weevilinfested grain must not exceed 10% in products sold for livestock feeds, and only 1 3% in products to be used for human foods.
FIND OUT MORE E. LEPPIK, C. PINIER and B. FREROT. Paysage chimique d'une agrobiocénose : un exemple, la féverole et son ravageur spécialiste Bruchus rufimanus. AFPP – 10th International Conference on Pests in Agriculture (in French only) Montpellier – 22 and 23 October 2014.
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