PARAQUAT
Trade Name: Gramoxone
Group 22
Site of Action: Photo system I - electron diverters
Symptoms:
- Within a few hours, in full sunlight, the plant wilts and dries out
- In 1- 3 days complete foliar necrosis occurs
- Injury from drift can occur and presents itself as spots of dead leaf tissue wherever there is contact by spray droplets
Uptake and Translocation
- Absorbed by foliage and green bark
- Little or no translocation
Persistence
- Highly persistent but residues are tightly adsorbed and unavailable in the soil
- Essentially no residual activity in soil
- Half-life in field: 1000 days
Symptoms
- Initially yellow spots turning tan to bronze spots where spray contacts tissue
- Most severe on leaves near the ground
Often Confused With
Black rot: dark pycnidia in lesions
Scouting Notes
Look for yellowed and dying weeds under the vines.
Management Notes
- Avoid contact with fruits, new shoots or foliage.
- Do not spray under windy conditions.
- Use a shielded sprayer.
- Use low pressures that produce large droplet sizes to avoid drift.
- Grow tubes provide excellent protection of newly planted vines from herbicides.
Click to enlarge.
