Question

The first bioherbicide developed in 1981 was based on
A. Phytophthora palmivora
B. Phytophthora infestans
C. Bacillus thuringiensis
D. Azadirachta indica.

Answer 1

Hint: Herbicide is a category of chemical agent that is mainly used to kill or control or inhibit the growth of unwanted plants such as pests, unwanted plant species, agricultural weeds, ect. Selective herbicides are used to kill selective weeds without damaging the main crop.

Complete answer:
Herbs or weeds are the extra-growing plants that grow very fast with the main crop and are the cause of the problems for all farmers around the world. These plants absorb nutrients and important nutrition like water and sunlight from the surrounding of the main crop and thus the main crop competes with these plants to get the nutrition. This makes the main crop retarded in growth as all the necessary nutrition required for the growth is absorbed by these fast growing herbs and weed.
Different types of herbicides are available in the market among which the most important category of the herbicides is the bio-herbicides, as they are environment friendly and efficient to treat with unwanted plants. So when we use biological agents like bacteria, fungi, algae, etc then, it is known as bioherbicides.
Among all the options the first bio-herbicide is a mycoherbicide, based on a fungus called Phytophthora palmivora. It was developed in 1981 to deal with Morrenia odorata, that is the type of milkweed vines, in fields of citrus plants and since then it is used till today as a bio-herbicide.

Hence, the correct answer is option (A).

Note: Among all the four above herbicides, Phytophthora palmivora is the type of fungus that affects potatoes and tomatoes crop known as a potato blight.Bacillus thuringiensis is the category of bacterias that produces toxins that kill the pest, resistant to bollworm, affecting the cotton plants as an example. Azadirachta indica is the scientific name of Neem plant and is generally used as a bio-pesticide for various agricultural products.