Spot spraying, chipping, hand roguing and wiper technologies
Where new weed infestations occur in low numbers, eradication may be possible. In such situations more intensive tactics to remove weeds can be used in addition to 'ongoing' management tactics which aim to minimise weed impact.
Vigilance and attention to detail can be the difference between eradication and a prolonged and costly problem. Make sure you correctly identify the weed, understand the biology (when does it grow, when does it reproduce etcetera) and identify what control tactics are best suited to the weed at each growth stage.
To ensure the eradication program is successful:
- instigate accurate future monitoring by marking isolated infestations
- isolate the area of infestation to reduce the risk of further spread.
Techniques for localised eradication
Roguing
Roguing refers to hand pulling or chipping of weeds prior to flowering or seed-set. It is also used in seed crops to reduce the chance of spreading weeds in the seed and when other options of controlling the weed are limited. If roguing is carried out after seed is physiologically mature, both the plants and their seeds should be contained and carefully disposed of. Roguing is an effective method of eradicating a new infestation in annual crops, despite being labour intensive and expensive.
Spot spraying
This method is a quicker alternative to hand roguing and can be used to sterilise weed seed. Spot spraying usually involves the application of a non-selective herbicide to individual weeds using a sprayer in a backpack or mounted on an all terrain vehicle (ATV). The sprayer should have a single nozzle on a wand attached to a flexible hose. A boom sprayer fitted with weed detector units may also be used for applying non-selective herbicides to low-density infestations in fallows.
Wick wiping
Wick wiping performed with a hand-held rope-wick wiper is an alternative to spot spraying when there is the possibility of herbicide drift onto sensitive adjacent plants. It is particularly useful if the weed is taller than the crop canopy. There are multiple 'wiper technologies' available, including wick wipers, rope wipers, carpet wipers and weed wipers.