Bayer product manager Neil Thompson said the label extensions confirmed their unique role as dual-purpose products during the crop's rapid canopy growth phase.
"Their fenamidone component provides good protection against primary Alternaria infection - which can come in two to four weeks from emergence," he said. "And propamocarb brings the systemic activity needed to protect new growth against late blight."
Agrovista technical manager Dr Mark Palmer said that with early blight, timing was key because the fungicide options are protectant.
He said: "This means growers of susceptible varieties need to build fungicide programmes that include the necessary protection while still achieving the main objective of securing late-blight control."
"Consento provides the required dual activity through the rapid canopy growth phase. From stable canopy onwards Electis (zoxamide + mancozeb) is an appropriate dual-activity option to bring in and adding mancozeb to the core late-blight programme also helps to bolster protection."
However, Palmer warned growers that high early-blight infection risk periods - typically created by warm, dry weather in alternation with short periods of moisture - tend to be more frequent from mid season onwards. "At these times, you have to work in the Alternaria-specific treatments - Olympus (azoxystrobin + chlorothalonil) or Signum (boscalid + pyraclostrobin)."
Previous history is also an important consideration, he added. "Susceptible varieties grown in the close vicinity of fields where crops were infected with early blight the previous year are more at risk. Like late blight, the pathogen survives on dumps and volunteers are the primary innoculum source. It's yet another reason to be strict with hygiene measures."