Button grass (Dactyloctenium radulans) is a native species found throughout Australia that is a common summer weed species and (like most summer grass weeds), depletes soil moisture and nutrients, reducing the yield potential of the subsequent crop. Summer weeds also act as a green bridge for crop pests and disease that can result in additional crop damage.
Button grass (also known as finger grass) is a summer annual or ephemeral species (that is, a species with a short life cycle, surviving as long as summer moisture is available) that grows semi erect, with spreading branches forming leafy tufts. A single plant can form up to 45 primary tillers and has both prostrate and erect tillers. The prostrate tillers develop roots at the node and branch into 7-8 secondary tillers which can allow a single plant to spread over an area of 1.5m diameter.
The plant develops 2-3 seed heads on the end of each tiller with each seed head consisting of 3-11 compact spikes in a finger-like arrangement. The individual spikes are 5-13mm long and contain overlapping spikelets, which contain 5-11 seeds per spikelet (approximately 8000 seeds/plant or 32 000 seeds/m2). Entire spikes (with the spikelets attached) are shed from the plant to disperse the seeds. The seeds are less than 1mm long, and closely resemble brown grains of sand.
There is no evidence of herbicide resistance in button grass, however glyphosate is commonly overused and button grass is at high risk of developing resistance to this active ingredient.
Tactics for integrated weed management
Button grass is a widespread weed in Australia and is favoured by no tillage farming systems as a result of greater germination of seeds on the soil surface. This weed can be effectively managed with an integrated weed management (IWM) plan.
Like most summer weeds, dusty, moisture stressed button grass plants at the height of summer are difficult to control. Button grass is one of the first summer weed species to emerge in the season, but it is also one of the first species to become moisture stressed, making older plants poorly responsive to herbicides. In very hot conditions, high rates of glyphosate alone or glyphosate followed by Imtrade Para-Trooper® in a double knockdown treatment give excellent control of plants at all growth stages.
In a single pass application at a rate of 3L/Ha Imtrade Para-Trooper has shown to provide effective control of Button Grass. In a double knock application at a rate of 2L/Ha Imtrade Para-Trooper has shown to provide excellent control of Button Grass.
Trial work in the northern NSW cropping region has indicated that higher water rates of up to 200L/Ha significantly improves control when using Imtrade Para-Trooper.