Hint: Herbicide is usually a chemical agent that is used for obstructing the growth of unwanted plants, residential or agrarian weeds and invasive species. It's main benefit is that it reduces the cost of labour due to it's easy application. For example; Acetochlor,Atrazine,Amitrole, Dinosep.
Milk vine weeds are toxic climbing weeds, which produce a milky sap which is fatal and deters many herbivores.
Now let us analyze the given options:
Option A: 2,4 - D is a systemic herbicide which kills most broadleaf weeds resulting in wild growth in them but grasses such as cereals and grassland are significantly unaffected. It is commonly used.Hence, this option is incorrect.
Option B: Phytophthora palmivora has been utilized as an post emergent mycoherbicide to regulate milkweed or strangler vine which is a crucial issue on citrus in south Florida. It results in the loss of seedlings and older plants Thus, option B is correct.
Option C: Pyrethrins are usually derived from Chrysanthemum flowers. They are generally sprayed on flowers to control mosquitoes, fleas, flies, moths, ants, and many other pests. Hence, this option is incorrect.
Option D: Since option B is correct, this option stands invalid.
Therefore, the correct answer is option ‘B’.
Note: Herbicides are mainly used in agriculture and in landscape turf management. They are also applied in total vegetation control (TVC) programs for the sustenance of highways and railroads. The USDA is accountable for testing crops to ensure that they do not go above the tolerances. FDA has the regulatory power to implement liabilities for non-compliance. Producers are lawfully and ethically expected to use herbicides according to the EPA authorized label instructions.