Predicting herbicidal plant mortality with mobile photosynthesis meters

• Published in: Weed research Vol. 51; no. 1; pp. 12 - 22
• Main Authors: KEMPENAAR, C, LOTZ, L A P, SNEL, J F H, SMUTNY, V, ZHANG, H J
• Format: Journal Article
• Language: English
• Published: Oxford, UK Blackwell Publishing Ltd 01.02.2011; Wiley-Blackwell
• Subjects: australia; Biological and medical sciences; challenges; Chemical control; decision support system; dose optimisation; Fundamental and applied biological sciences. Psychology; herbicide efficacy; MLHD; Parasitic plants. Weeds; pavements; photosynthesis; Phytopathology. Animal pests. Plant and forest protection; resistance; sustainable herbicide use; weed-control; Weeds; Decision support system; dose optimisation; herbicide efficacy; Treatment efficiency; Mortality; Pesticides; Prediction; System sustainability; Mobile; Herbicide; Optimization; sustainable herbicide use; Weed science; Photosynthesis; Dose; Chemical weed control; MLHD
• ISSN: 0043-1737; 1365-3180
• DOI: 10.1111/j.1365-3180.2010.00823.x

Kempenaar C, Lotz LAP, Snel JFH, Smutny V & Zhang HJ (2011). Predicting herbicidal plant mortality with mobile photosynthesis meters. Weed Research 51, 12–22. Summary Herbicide dose optimisation, i.e. maximising weed control and crop yield with herbicide dose, is an important part of integrated weed management strategies. However, the adoption of optimised dose technology and variable rate application has been limited because of the relatively long period between herbicide treatment and the time when efficacy can be visually assessed. Herbicide dose optimisation could therefore benefit from simple methods that allow early prediction of plant mortality. Early prediction would allow better management decisions, e.g. timely retreatment in case of uncontrolled weeds. The focus of this study was the relationship between leaf photosynthesis soon after herbicide treatment and subsequent plant mortality, with the aim of determining whether the former could predict the latter. Data from 28 glasshouse experiments were analysed. In these experiments, herbicides from five modes of action groups were tested on five plant species. Leaf photosynthesis was measured with two mobile meters up to 1 week after herbicide treatment. Leaf photosynthesis was affected by plant species, leaf number, herbicide species, dose and time. Large changes in leaf photosynthesis were observed with photosynthesis‐inhibiting herbicides, intermediate changes were noted with glyphosate, glufosinate‐ammonium and sulcotrione, and no changes were detected with MCPA. Threshold values associated with plant mortality were then determined. These values can be used to assess the risk of uncontrolled weeds treated with variable herbicide doses.