Explanation:

An example of microbial biocontrol agents that can be introduced in order to control
butterfly caterpillars is the bacteria Bacillus thuringiensis. So, 1 is correct.
Microbial pesticides also include viruses for e.g. entomopathogenic fungi or viruses. So, 2 is correct.
A biological control being developed for use in the treatment of plant disease is the fungus Trichoderma. Trichoderma species are free-living fungi that are very common in the root ecosystems. They are effective biocontrol agents of several plant pathogens. So, 3 is correct.
The very familiar beetle with red and black markings – the Ladybird, and Dragonflies are useful to get rid of aphids and mosquitoes, respectively. So, 4 is also correct.