lecture 14 groups 5,6,7 Flashcards
groups 5,6,7 inhibit?:
Photosynthesis and photosystem2
why are group 5,6,7 in different groups?
6 different binding site
5,7 same but different binding behavior
group 5 herbicides
cynanazine - corn
Bromacil - soil sterilant
Desmedipham - sugar beets
Hexazinone - alfalfa
Metribuzin - potatoes, peas, cereals
Phenmedipham - sugar beets
Simazine - alfalfa
Pyrazon - beets
group 5 target site protein in what?
D1 protin in PS2
group 5 inhibits and MOA
inhibits PS2
affects binding of plastoquinone
PS2 collects light and supplies electrons
cells stop functioning
group 5 symptoms
develop rapidly
injury in older leaves
bleaching
plants die within 2 weeks
group 5 selectivity
metabolism in crops higher than weeds
selectivity by rapid metabolism of herbicide to non-toxic metabolites
group 5 herbicide resistance
resistance in many species
group 6 MOA
Inhibition of photosynthesis
Photosystem 2
reduces availability of plastoquinone to accept electrons
group 6 symptoms
similar to group 5
blotchy, inter-venial chlorotic patches on leaves
rapid necrosis of leaf tissue
group 6 selectivity
rapid metabolism to non-toxic compounds by resistant plants
will cause damage if applied under stressful conditions
are there many group 6 resistant weeds?
very few
