15 March 2022
Alter ratios to keep costs down, says specialist
POTATO growers feeling the pinch of price pressures this spring could look at simplifying herbicide mixes for more cost-effective pre-emergence options, according to Syngenta Technical Manager, Andy Cunningham.
Greater use of natural regeneration breaks and cover crops in arable rotations means the weed seed burden of some of the more troublesome weeds for potatoes are on the increase. Cleavers, mayweed and shepherd’s purse, for example, can proliferate rapidly in a single season.
“Recent potato herbicide introductions have increased agronomists’ options. In many instances, however, simple mixes can achieve everything growers want, at lower relative cost,” said Andy.
“Many of the key weeds that burden early potato emergence can be controlled, using the strength of mixes to widen the specific weed spectrum,” he advised.
For example, recent season’s trials had shown a mixture of Defy (prosulfocarb) at 4.0 l/ha + metabromuron at a reduced rate of 1.0 l/ha, for example, achieved full control of assessed broad-leaved weeds, including chickweed, mayweed, cleaver and shepherd’s purse. Untreated weed pressure from these species was more than 70 per m2.
That combination, typically costing just £43 per hectare at current prices, was even more effective overall compared to Defy at 3.0 l/ha and metabromuron at a rate of 2.0 l/ha, which would cost nearly £55/ha and proved slightly weaker on cleavers.
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