Question

Which of the following is not used as a biopesticide?
A) Bacillus thuringiensis
B) Trichoderma harzianum
C) Nuclear polyhedrosis virus (NPV)
D) Xanthomonas campestris

Answer 1

Biopesticides are those pesticides which are derived from nature such as animals, plants, bacteria, etc. Such pests rely on natural predation, parasitic or chemical relationship for their management.

Complete answer:

Xanthomonas Campestris is a bacteria that causes disease in plants, meaning this bacteria is itself a pest.It caused” Black-rot” in crucifers by darkening the vascular tissues. So, it is not a biopesticide.
Bacillus thuringiensis is a bacteria used as microbial pesticide. These bacteria are found in sachets as dried spores which are mixed with water and sprayed onto vulnerable plants such as brassicas and fruit trees, where these are eaten by the insect larvae. In the gut of the larvae, the toxin is released and the larvae get killed.
Trichoderma harzianum is a fungus used to treat plant diseases.These are free-living fungi that are very common in the root ecosystems. These fungi are effective biocontrol agents of several plant pathogens.
Nuclear polyhedrosis virus (NPV) belongs to the sub group Baculoviruses are pathogens that attack insects(moths are butterflies) and other arthropods. This virus causes a caterpillar or chrysalis to literally turn to a foul-smelling black liquid. In most instances, the caterpillar becomes sluggish, crawls higher on a plant, building, or cage, and attaches itself by it's prolegs. It dies and hangs in either an inverted V or in a straight line.

Hence the correct answer is option ‘D’.

Note: Biocontrol of plants refers to the use of biological methods for controlling plant diseases and pests. Use of chemicals like insecticides and pesticides causes great harm. Such chemical insecticide and pesticides are toxic and extremely harmful, to human beings and animals alike, and have been polluting our environment (soil, ground water), fruits, vegetables and crop plants. The use of weedicides which are used to remove weeds pollute the soil.