Pacific Pests, Pathogens and Weeds

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Summary

• Worldwide distribution. In Australia, but NOT in Pacific island countries.
• Aggressive weed especially in pastures (poor nutrition, overgrazed or following drought), cultivated land, open woodlands, grasslands, parks, wastelands, roadsides. Massive early (6-10 weeks) seed production. Environmental weed in competition with native species. Economic impacts from poisoning cattle (acute and chronic): lower carrying capacity, weed management, changing from dairy and beef to sheep/goats. Horses susceptible.
• Spread: stems root from nodes, seed on the wind, birds, animals (including stock), on clothing, and contaminant (hay, other seeds, machinery, vehicles).
• Biosecurity: check pasture seed.
• Biocontrol: none.
• Cultural control: hand-weeding, slashing; maintain vigorous healthy pastures, do not overgraze; use sheep/goats; clean machinery/vehicles; use only weed-free hay, and monitor.
• Chemical control: in Australia, 2,4-D; metsulfuron-methyl; bromoxynil; bromoxynil + aminopyralid; bromoxynil + diflufenican; fluroxypyr + aminopyralid; picloram + triclopyr + aminopyralid.