The company blames the move on the current dry conditions and says it will review the advice should rainfall return to a more normal level.
There is concern that the application of Reglone at 1.0 l/ha in the current conditions will result in tuber damage to target potatoes.
If a SMART test returns a borderline result, Syngenta does support the use of Reglone at 0.5 l/ha, providing the haulm is senescing (low vigour).
Advice on how to carry out a SMART test and what to do in response can be found on the Reglone product label.
View the Reglone product label online here
Similar advice may apply to other pesticides that contain diquat. For instance, UPL have recently issued a technical update for the use of Mission 200 SL in dry conditions. The company says checks must be carried out before the pesticide is applied, including testing soil moisture as follows:
- Dig down with a spade and take a soil sample from the centre of the ridge 5 cm below the lowest tuber
- Gently squeeze the soil sample into a ball with one hand. If it is sufficiently moist the soil will remain as a ball. If the soil sample collapses then the test has failed and Mission 200SL should not be used.