Not a scientist or science reporter, but it strikes me that the headline (and content) of the article should include 'that we know of'. Is that silly of me, or is it expected from the reader to know that this is always implied?
"Leaf miners identified as oldest insect plague in the history of Earth"
With many things in science, there isn't anything like that degree of incomplete information. We can talk about, say, a chemical reaction with extremely high certainty.
Also, in many cases a theory provides implicit context which makes the resulting statements true in the context of that theory. We can say that in general relativity, a black hole has a singularity at its center. There's no doubt about that, but it doesn't tell us whether actual physical black holes contain singularities.