Achtung: hohPublica wurde am 18.11.2024 aktualisiert. Falls Sie auf Darstellungsfehler stoßen, löschen Sie bitte Ihren Browser-Cache (Strg + Umschalt + Entf). *** Attention: hohPublica was last updated on November 18, 2024. If you encounter display errors, please delete your browser cache (Ctrl + Shift + Del).

Institut für Phytomedizin

Permanent URI for this collectionhttps://hohpublica.uni-hohenheim.de/handle/123456789/14

Browse

Browsing Institut für Phytomedizin by Journal "Plants"

Type the first few letters and click on the Browse button
Now showing 1 - 2 of 2
  • Thumbnail Image
    Publication
    Agronomic and technical evaluation of herbicide spot spraying in maize based on high-resolution aerial weed maps - an on-farm trial
    (2024) Allmendinger, Alicia; Spaeth, Michael; Saile, Marcus; Peteinatos, Gerassimos G.; Gerhards, Roland; Allmendinger, Alicia; Department of Weed Science, Institute for Phytomedicine, University of Hohenheim, 70599 Stuttgart, Germany; (A.A.);; Spaeth, Michael; Department of Weed Science, Institute for Phytomedicine, University of Hohenheim, 70599 Stuttgart, Germany; (A.A.);; Saile, Marcus; Department of Weed Science, Institute for Phytomedicine, University of Hohenheim, 70599 Stuttgart, Germany; (A.A.);; Peteinatos, Gerassimos G.; ELGO-DIMITRA, Leof Dimokratias 61, Agii Anargiri, 135 61 Athens, Greece;; Gerhards, Roland; Department of Weed Science, Institute for Phytomedicine, University of Hohenheim, 70599 Stuttgart, Germany; (A.A.);; Rossi, Vittorio
    Spot spraying can significantly reduce herbicide use while maintaining equal weed control efficacy as a broadcast application of herbicides. Several online spot-spraying systems have been developed, with sensors mounted on the sprayer or by recording the RTK-GNSS position of each crop seed. In this study, spot spraying was realized offline based on georeferenced unmanned aerial vehicle (UAV) images with high spatial resolution. Studies were conducted in four maize fields in Southwestern Germany in 2023. A randomized complete block design was used with seven treatments containing broadcast and spot applications of pre-emergence and post-emergence herbicides. Post-emergence herbicides were applied at 2–4-leaf and at 6–8-leaf stages of maize. Weed and crop density, weed control efficacy (WCE), crop losses, accuracy of weed classification in UAV images, herbicide savings and maize yield were measured and analyzed. On average, 94% of all weed plants were correctly identified in the UAV images with the automatic classifier. Spot-spraying achieved up to 86% WCE, which was equal to the broadcast herbicide treatment. Early spot spraying saved 47% of herbicides compared to the broadcast herbicide application. Maize yields in the spot-spraying plots were equal to the broadcast herbicide application plots. This study demonstrates that spot-spraying based on UAV weed maps is feasible and provides a significant reduction in herbicide use.
  • Thumbnail Image
    Publication
    Role of benzoic acid and lettucenin A in the defense response of lettuce against soil-borne pathogens
    (2021) Windisch, Saskia; Walter, Anja; Moradtalab, Narges; Walker, Frank; Höglinger, Birgit; El-Hasan, Abbas; Ludewig, Uwe; Neumann, Günter; Grosch, Rita
    Soil-borne pathogens can severely limit plant productivity. Induced defense responses are plant strategies to counteract pathogen-related damage and yield loss. In this study, we hypothesized that benzoic acid and lettucenin A are involved as defense compounds against Rhizoctonia solani and Olpidium virulentus in lettuce. To address this hypothesis, we conducted growth chamber experiments using hydroponics, peat culture substrate and soil culture in pots and minirhizotrons. Benzoic acid was identified as root exudate released from lettuce plants upon pathogen infection, with pre-accumulation of benzoic acid esters in the root tissue. The amounts were sufficient to inhibit hyphal growth of R. solani in vitro (30%), to mitigate growth retardation (51%) and damage of fine roots (130%) in lettuce plants caused by R. solani, but were not able to overcome plant growth suppression induced by Olpidium infection. Additionally, lettucenin A was identified as major phytoalexin, with local accumulation in affected plant tissues upon infection with pathogens or chemical elicitation (CuSO4) and detected in trace amounts in root exudates. The results suggest a two-stage defense mechanism with pathogen-induced benzoic acid exudation initially located in the rhizosphere followed by accumulation of lettucenin A locally restricted to affected root and leaf tissues.