Which bacteria are used for the control of pests that are harmful to cotton and fruit trees?

Gambusia is a/an .......

Which one of the following is $NOT$ a bacterial herbicide?

Biocontrol agent $Baculovirus$ causes diseases in which organisms?

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?

$A$ major pest eradicated through the release of sterile males is: