9 March 2001

Pgr claims disputed

CLAIMS by Syngenta that Moddus (trinexapac-ethyl) is the only pgr to increase rooting, tillering, and control lodging have been slammed by BASF business development manager John Peck.

"Chlormequat will do exactly the same thing and at much lower cost," he says.

Both pgrs are anti-giberellins, but Moddus blocks giberellin synthesis near the end of the pathway, which causes a very rapid stop to growth. There can then be a rush of compensatory growth which can cause a ragged appearance in the crop, he says.

The surge in subsequent growth is because there is a build up of pre-giberellin compounds in the plant behind the pgr blockage. Once the Moddus effect wears off these are rapidly converted to giberellins, leading to a growth spurt, he explains.

"Trinexapac-ethyl also requires a relatively high temperature to work, most say about 12C, whereas straight chlormequat works at about 8C, hence it is more effective at early timings."

&#8226 Syngentas Alistair Reid says Moddus is the only pgr to offer three-way lodging control. "We have the information to back it up."