Abstract
The joint effect of binary mixtures of the 4-hydroxyphenylpyruvate dioxygenase inhibitor isoxaflutole with glyphosate and metribuzin on Beta vulgaris was analysed with dose-response curves. The hypothesis was to test divergence from the Additive Dose Model (ADM), as a reference model. The Fvj parameter [(Fm - Fj)/Fm] and two new parameters, based on the slope at the J and the I step of the Kautsky curve, measured 2 days after spraying, and biomass 3 weeks after spraying, were used as responses. Synergistic effects of mixtures of isoxaflutole with numerous herbicides have been patented and were thus the working hypothesis. The shapes of isoboles, a contour plot of all mixtures of two herbicides that give the same effect, was variable, but the results of the mixtures with isoxaflutole, however, did not show statistically significant departure from the ADM. This applies to all endpoints: biomass and the Kautsky curve parameters, Fvj, Slope-I and Slope-J. The variability of isobole shapes is discussed, as is the use of statistical assessment of isobole parameters. The parameters from the Kautsky curves after 48 h predicted the isobole just as well as biomass after 20 days and could be used as a rapid scan for the divergence of joint action of mixtures from the ADM, long before visible symptoms develop.
| Original language | English |
|---|---|
| Journal | Weed Research |
| Volume | 51 |
| Issue number | 1 |
| Pages (from-to) | 23-32 |
| Number of pages | 10 |
| ISSN | 0043-1737 |
| DOIs | |
| Publication status | Published - Feb 2011 |