Amitrole
Trade Name: Amitrol 240
Registration status: This herbicide is not registered for use in tender fruit orchards.
When to suspect injury: Injury from amitrole may occur from drift from neighbouring fields, under windy conditions. Amitrole is a systemic herbicide so expression of symptoms may be delayed for several weeks. If you notice symptoms of bleached leaves, especially in the meristem, look carefully at neighbouring fields or lawns, and at other weeds in the treated area.
Herbicide Information: Knowing how the herbicide works will help to determine the likelihood of injury from either direct application or drift. Consider how the herbicide works in plants, behaves in soils and what symptoms are common in other plants.
Chemical Family : Triazole
Site of Action/Group: Inhibitors of carotenoid biosynthesis (WSSA Group 11)
General Symptoms in Plants
Symptoms in Fruit Trees
- White spots on leaves when droplets touch
- Bleached leaves in growing point if sufficient amounts drift onto actively growing trees
Uptake and Translocation
- Absorbed by foliage and roots
- Translocates well in xylem and phloem
- Accumulates in growing regions of plant
Persistence and Residual Activity
- Average persistence
- Half life in field: 14 days
- Residual activity is approximately 2-4 weeks in moist, warm soil
If you suspect herbicide injury, laboratory analyses of herbicide levels in plant tissue are necessary to confirm the presence of herbicides, although symptoms may be helpful in diagnosing which herbicides caused the problem.
Both damaged and healthy plant tissues should be analyzed, because comparison levels are not readily available for many herbicides. Contact your lab for instructions on which plant parts should be sampled, how to handle and ship the sample, and what costs are involved to ensure an accurate and timely diagnosis.
