Baculoviruses attack on:

The correct answer is Option (2) → Arthropods

Option (2) Arthropods — Correct. They attack insects and other arthropods, so they are used as biocontrol agents.

NCERT Extract:
Microbes as Biocontrol Agents – “… Baculoviruses are pathogens that attack insects and other arthropods. The majority of baculoviruses used as biological control agents are in the genus Nucleopolyhedrovirus. These viruses are excellent candidates for species-specific, narrow spectrum insecticidal applications. They have been shown to have no negative impacts on plants, mammals, birds, fish or even on non-target insects.”