Encapsulated Pendimethalin Herbicide Formulations Released
From Farmers Weekly Interactive:
“But both Makhteshim (Cinder) and BASF (Stomp Aqua) have been working on a new formulation that uses polymer technology to encase the active ingredient within capsules that are suspended in water.
It is the encapsulation that helps minimise staining and makes rinsing of jugs and cans much easier compared with EC formulations, Sarah Mountford-Smith of BASF explains. “The active ingredient is locked inside the polymer coat preventing direct contact of the pendimethalin with the walls of the jug.”
Once diluted in the spray tank the capsules absorb water causing the polymer wall to expand and swell. Some rupture in the spray tank and during the course of spraying to release the active ingredient. Those that don’t rupture are primed to release on further contact with moisture, Mrs Mountford-Smith explains.
Typically in UK conditions that means the capsules will open at or soon after spraying, although if it does remain dry the controlled release should mean the capsules open when there is sufficient moisture to encourage weed germination.
Another potential advantage is for min-till users, she adds. “One of the properties of pendimethalin, particularly the EC formulation, is it has an affinity for organic matter, such as crop trash, which can effect efficacy. Micro-encapsulation minimises that binding meaning it should be delivered to the soil where it needs to be for weed control.”
Field trials will look at that theory in more detail this autumn, although other trials have confirmed some benefits, she says. In non-trashy seed-beds the performance of the different formulations is comparable.”