Effective post-emergence weed control in maize
ADAMA New Zealand Commercial Manager, Doug Speers, recommends a tank-mix of Adapt® herbicide to control annual grasses and Mesoflex® herbicide to target broadleaf weeds.
“The application of Adapt and Mesoflex is a time-tested maize post-emergence herbicide combination that is cost-effective and efficacious,” says Doug.
Adapt provides post-emergence control of some perennial and annual grasses including barnyard grass, bristle grass, couch regrowth, crowfoot grass, Kikuyu, pasture grasses (volunteers), rough bristle grass, smooth witchgrass, summer grass and wild oats. These grasses can escape the pre-emergence herbicide application due to dry soil conditions at the time of application, trash laden soils, and/or poor spray coverage. Adapt also controls some broadleaf weeds.
Mesoflex provides effective broadleaf weed control post-emergence including Bathurst bur, black nightshade, chickweed, dandelion, fathen, fennel, fishtail oxalis, hairy nightshade, galinsoga, mallow, redroot, seedling docks, spurrey, stagger weed, twin cress, willow weed, and wire weed.
Adapt and Mesoflex are systemic herbicides rapidly absorbed by weed leaves and translocated throughout the plant. Applying both herbicides as a tank mix ensures that a broad spectrum of weeds are controlled with one easy application that is rainfast six hours later.
Doug says post-emergence spraying, like other aspects of crop management, takes planning. “Often growers wait too long before spraying. The rule of thumb is to apply about five to six weeks after planting, depending on when the crop is planted and its speed of growth. Ideally, it should be before weeds have reached the four-leaf stage.”
An initially clean-looking paddock may experience heavy weed germination later. Buried weed seeds can delay their germination until they get closer to the soil surface, and when conditions are more favourable, they emerge. For this reason, Doug recommends regularly monitoring the maize crop for weeds and other issues.
Doug says another benefit to controlling weeds in silage maize crops is that it helps eliminate an attractive environment for the Tropical Armyworm, Spodoptera litura, which can do considerable damage to crops. Weeds can also potentially provide a home for the crop-killing fall armyworm, Spodoptera frugiperda, which was recently found in Waikato. Mesoflex, Doug adds, can be applied as a pre-emergence herbicide at higher rates to control broadleaf weeds.