Which was the first commercially developed insecticide?

The fish used for the control of mosquitoes,known as the larvicidal fish,is ..............

Consider the following statements:
$I.$ Ladybirds and dragonflies are used to get rid of aphids and mosquitoes.
$II.$ The bacteria $Bacillus$ $thuringiensis$ $(Bt)$ are used to control butterfly caterpillars.
$III.$ $Trichoderma$ $sp.$,free-living fungi,are present in root ecosystems where they act against several plant pathogens.
$IV.$ $Rhizobium$ is a symbiotic bacterium that lives in the stem of legumes.
Which of the statements given above are correct?

Sporeine was developed in

Which fish is introduced into ponds to feed on mosquito larvae?

What is the use of biological organisms or products derived from them to control crop pests and diseases called?