Timing Fazor for effective performance

UK - August 02, 2007

Volunteer potatoes are a difficult and important problem to control on most farms, particularly with the increase in rented land being used for potato growing.  A foliar application of Fazor (maleic hydrazide) in second earlies and maincrop potatoes can reduce the viability of small daughter tubers and suppress volunteers developing in the field after harvest.  But this year, because many crops are under stress, growers need to be extra careful when applying this product for its best effect, advises Dow AgroSciences.

"Fazor is applied through a conventional sprayer to the growing crop, when the crop is at the correct growth stage and environmental conditions are suitable.  Timing of Fazor is critical to its effectiveness and growers must follow guidelines on conditions of application closely, particularly when it comes to avoiding stressed crops.  The label states that crops under stress should not be treated: this means crops under drought stress, those suffering from pest and disease attack and more pertinently this year water-logged crops.  If the crop is under stress, you should try to rectify the problem before applying Fazor," says Andy.

Andy explains that the ideal timing for Fazor is when the crop is actively growing and the haulm is mostly green, but with a few lower leaves turning yellow and most of the flowers having fallen.  Growers calculate back at least three, and not more than five weeks, from their intended burn down date: this allows sufficient time for the chemical to be taken up by the leaves and translocated to the tubers where it acts.  Optimum timing is five weeks before harvest.  Each field should then be checked for maturity and tuber size using test digs.  The smallest tubers required to reach marketable size should be greater than 25 mm across.  If too many tubers are going through the 25mm riddle, it is worth waiting a week and re-sampling."

"Because of the very difficult growing conditions we have experienced so far this year, extra caution will be needed particularly in crops that are under stress.  If the crop is stressed, there maybe reduced translocation of the active ingredient to the tubers and so a reduced effect on the tubers.  Yield is not often affected but tuber quality and size maybe," explains Mr. Leader

"Fazor is also not particularly rainfast and so a period of 24 hours without rain or irrigation will be needed.  As with most inputs in potatoes this year, application of Fazor will need some thought and planning.  But with volunteers being such a major problem in most arable rotations, it will be worthwhile adopting an integrated approach to their control across the rotation, including the use of Fazor as the in-potato-crop solution," says Andy.