432GJIVA

3279

13 avril 2021 09:37

13 avril 2021 09:37

North Carolina is the second largest producer of organic sweetpotatoes (Ipomoea batatus L.) behind California. In 2016, there were 3,200 acres of organic sweetpotatoes produced in the state, a 42% increase from 2014. Despite an increase in acreage, organic sweetpotato yields continue to be limited by weed competition and direct feeding from wireworm larvae (Coleoptera: Elateridae). The goal of this project was to explore sweetpotato management opportunities that could address these production limitations in the organic production system. To understand linkages between wireworms and the organic production system, I evaluated the management strategies in small plot organic studies including different cover crop blends and sweetpotato varieties. I also measured the movement of adult click beetles in the surrounding sweetpotato agroecosystem. The first study examined autumn planted cover crops as an organic form of fertility and weed control. My role was to document if the presence of cover crops had an effect on wireworm abundance and sweetpotato root damage. Over this two-year study, I planted cover crops in the autumn and terminated them the following spring. After termination, we planted a new wireworm resistant sweetpotato variety (cv. Monaco – formerly NC04-0531) and a common susceptible variety (cv. Covington). After sweetpotato harvest, I measured the number of wireworm holes present on roots and related root injury to cover crop type and sweetpotato variety. I found that the resistant sweetpotato variety had the least amount of wireworm damage when compared to the standard susceptible variety. Cover crop type was not significantly related to the amount of wireworm injury observed at the end of the growing season. The second study focused on generating new knowledge about the activity of corn wireworm, Melanotus communis Gyllenhal (Coleoptera:Elateridae) using a recently identified female-produced sex pheromone, 13-tetradecenyl acetate. Melanotus communis is a major pest of many crops in North Carolina. This insect has a semi-voltine life history and can spend multiple years in its larval stage, which as a result, creates challenges for cultural control strategies (i.e., crop rotation). Currently, we do not understand when and where M. communis adults are most active in the sweetpotato production system. With very little contemporary information about the ecology of adult M. communis in North Carolina, my second study explored the use of pheromone baited pitfall traps to better understand adult M. communis activity in time and space. To do this, I used pitfall traps that were placed in the ground with a 13-tetradecenyl acetate pheromone lure to attract adult male M .communis. Traps were monitored for M. communis weekly and I related counts to the type of adjacent crop. I found that 13-tetradecenyl acetate was effective at capturing adult M. communis, with pheromone baited traps consistently catching more individuals than the non-baited control. I also found that adult M. communis are more abundant near known host crops for their larvae (i.e. sweetpotato and corn) when compared to unattractive host crop control fields (i.e. cotton). Together, these experiments provide useful insight into wireworm ecology and management for organic sweetpotato production.

None

• AB - Spécifique
• FREDO adventice
• FREDO biologie des nuisibles
• FREDO fertilisation
• FREDO lutte
• FREDO santé végétale
• GEO Californie
• GEO Etats-Unis
• wireworms
• agroecosystem
• cover crop
• management practices
• patate douce
• pest control
• racine
• rendement

17/02/2021

17 février 2021