Publication Date
1993
Description
The mat-forming weed Hieracium pilosella {mouse-eared hawkweed) has become a major problem of tussock grasslands in New Zealand. Thirteen trials investigating methods of hawkweed control were laid down during 1975-80, monitored for 3 years, and subsequently reassessed in 1991. When grazing was excluded hawkweed was reduced from 60 to 3% ground cover within 18 months by topdressing and oversowing or overdrilling legumes; and to 22% by the use of the herbicides, 2,4 D and mecoprop-MCPA-dicamba. With grazing and no further topdressing, these improved lands reverted to hawkweed at a mean rate of 2-3%/year, as did overgrazed unimproved tussock grassland. In contrast, where hawkweed had been present at 60% or more of ground cover for many years it declined to about 30% over a period of 9 years provided there was no overgrazing. Climate values relating to temperature, drought days and rainfall can be used to identify probable mouse-enr hawkweed nucleus sites and also the likely invasion of the weed from the nucleus sites.
Citation
Cossens, G G. and Boswell, C C., "Residual Effects of Oversowing, Overdrilling, and Herbicide in the Long-Term Control of Hieracium pilosella in Otago, New Zealand" (2024). IGC Proceedings (1993-2023). 13.
https://uknowledge.uky.edu/igc/1993/session46/13
Included in
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Residual Effects of Oversowing, Overdrilling, and Herbicide in the Long-Term Control of Hieracium pilosella in Otago, New Zealand
The mat-forming weed Hieracium pilosella {mouse-eared hawkweed) has become a major problem of tussock grasslands in New Zealand. Thirteen trials investigating methods of hawkweed control were laid down during 1975-80, monitored for 3 years, and subsequently reassessed in 1991. When grazing was excluded hawkweed was reduced from 60 to 3% ground cover within 18 months by topdressing and oversowing or overdrilling legumes; and to 22% by the use of the herbicides, 2,4 D and mecoprop-MCPA-dicamba. With grazing and no further topdressing, these improved lands reverted to hawkweed at a mean rate of 2-3%/year, as did overgrazed unimproved tussock grassland. In contrast, where hawkweed had been present at 60% or more of ground cover for many years it declined to about 30% over a period of 9 years provided there was no overgrazing. Climate values relating to temperature, drought days and rainfall can be used to identify probable mouse-enr hawkweed nucleus sites and also the likely invasion of the weed from the nucleus sites.
