Thifensulfuron-methyl
Trade Names: Pinnacle
Group 2
Site of Action: Inhibitors of acetolactate synthase (ALS) and also called acetohydroxyacid synthase (AHAS)
Symptoms
Following POST emergent application:
- Within an hour the inhibition of ALS enzyme leads to a rapid cessation of cell division and plant growth
- Within 1- 2 weeks symptoms become visible
- Meristematic regions are the first to experience chlorosis and necrosis followed by general foliar chlorosis and necrosis
- More injury observed on tomatoes where Pinnacle is mixed with Prism (both Group 2 herbicides)
- Certain cultivars show greater sensitivity to Pinnacle
Uptake and Translocation
- Following foliar application, the herbicide is rapidly absorbed and translocated in both xylem and phloem to growing points
Persistence
- Half life of 5 days at 25°C (77°F) soil temperatures