PHYTOMA : Le balanin de la noisette (Curculio nucum, Curculionidae) et la punaise verte des bois (Palomena prasina, Pentatomidae) sont les principaux ravageurs indigènes des vergers de noisetier (Corylus avellana). En 2024, les pertes occasionnées par le balanin de la noisette et les différentes espèces de punaises (dont la punaise diabolique) ont entraîné une baisse significative de la production, et donc du chiffre d’affaires des producteurs. La compréhension précise des types de dégâts occasionnés par ces ravageurs sur la noisette est indispensable pour améliorer l’efficacité des traitements insecticides actuellement disponibles, dont la faible rémanence et le large spectre limitent leur pertinence dans une stratégie ciblée. Pour cela, l’ANPN a évalué l’impact de Curculio nucum et de Palomena prasina sur la croissance de la noisette. L’identification des symptômes doit permettre d’optimiser les stratégies de protection. Les résultats sont discutées dans cette review des récents papiers publiés par l'association.

Walnut trees are grown worldwide for their edible fruits, which have high nutritional value. To address climate change, researchers have studied walnut phenology to create cultivars adapted to warmer climates. The objective of this study is to propose a scale for phenological Persian walnut observations using the Biologische Bundesanstalt, Bundessortenamt, und CHemische Industrie (BBCH) codification and alignment with historical alphameric scales. Here, the principal growth stages (PGSs) of Persian walnut (Juglans regia L.) are described using stages from a previously available alphanumeric scale. This standardised phenological scale describes Persian walnut growth from the dormant vegetative state through reproductive budding and senescence. This phenological scale is expected to increase the efficiency of walnut phenological monitoring. Fifty-seven stages are used to describe the life cycle of Persian walnut in this BBCH scale. Of these 57 stages, 3 stages are dedicated to seed germination (PGS-0), 4 stages are dedicated to bud development (PGS-0), 7 stages are dedicated to leaf development (PGS-1), 4 stages are dedicated to stem elongation (PGS-3), 8 stages are dedicated to inflorescence emergence (PGS-5), 5 stages are dedicated to male flowering (PGS-6), 5 stages are dedicated to female flowering (PGS-6), 5 stages are dedicated to fruit development (PGS-7), 12 stages are dedicated to fruit ripening (PGS-8), and 4 stages are dedicated to leaf senescence (PGS-9).

Walnut trees are grown worldwide for their edible fruits of high nutritional value. To address climate change, researchers have studied walnut phenology to create cultivars adapted to warmer climates. The standardisation of walnut phenological observations is needed and the Biologische Bundesanstalt, Bundessortenamt und CHemische Industrie (BBCH) scale is the most accurate and internationally accepted for this purpose. Here, the principal growth stages (PGS) of Persian walnut (Juglans regia L.) are described using stages from a previously available alphanumerical scale. This standardised phenological scale describes Persian walnut growth from the dormant vegetative state through reproductive budding to senescence. This phenological scale is expected to increase the efficiency of walnut phenological monitoring. Fifty-seven stages were used to describe the life cycle of Persian walnut in this BBCH scale. Of these 57 stages, 3 stages are dedicated to seed germination (PGS-0), 4 stages to bud development (PGS-0), 7 stages to leaf development (PGS-1), 4 stages to stem elongation (PGS-3), 8 stages to inflorescence emergence (PGS-5), 5 stages to male flowering (PGS-6), 5 stages to female flowering (PGS-6), 5 stages to fruit development (PGS-7), 12 stages to fruit ripening (PGS-8) and 4 stages to leaf senescence (PGS-9).

The plant material: a tool to manage water resources. Example of the VEGET'eau project Optimizing irrigation in asparagus plantations.

Palomena prasina, the green shield bug (GSB), is widely distributed in the Eurosiberian region. In the Southwest of France, it is considered as a serious pest of hazelnuts, its feeding punctures lead to blank hazelnuts and kernel necrosis, causing heavy losses in commercial orchards. To date, no Integrated Pest Management strategy is available to control P. prasina. Control strategies often focus on the pests' spring-summer ecology, when they are in the field or in the vicinity of crops. However, the abundance of pest populations in crops is also related to their autumn-winter ecology. The present work focussed on the autumn-winter ecology of P. prasina to identify new opportunities for this pest suppression. We investigate (i) where P. prasina overwinters, (ii) if it aggregates in its overwintering sites and (iii) if it mates while overwintering. Samples were collected over a 2-year period in different ecosystems (forests, hedges, orchards), in human made structures and habitats (litter, bushes/trees, dead trees). The reproductive status of GBS individuals was monitored in winter, and in spring when they emerged from overwintering sites. Our results show that 97% P. prasina adults overwinter in the leaf litter of orchards and natural ecosystems and that 70% overwinter individually. The abundance of GSB in those sites is negatively correlated with litter temperature and positively correlated with humidity levels. Furthermore, adults only mate after leaving their overwintering site. Finally, unexpectedly, there was an important number of over-wintering adults hosting endoparasitoids (32%). The fact that GSB overwinters alone in the leaf litter means controlling its populations by destroying the overwintering sites is not a solution. All the same, our results point out some promising lines of research for developing methods to control P. prasina. First, the emergence traps, in particular the cone traps, proved efficient for collecting emerging adults and could be considered for monitoring. Moreover, our observations suggest the existence of long-range mating signals that could be exploited for trapping. Last but not least, the important number of overwintering parasitised adults is a potential biocontrol avenue.