My ears pricked up when I heard the local weatherman say that rain was expected to “invade into the River Valley.”
Why, I wondered, hadn’t he said that rain was expected to “invade the River Valley? The verb invade includes the sense of “into.”
invade: transitive verb. to enter in a hostile manner, or with armed force; to make an inroad or hostile incursion into.
The word derives from Latin invadere “go into, fall upon”
As a transitive verb, invade takes a direct object:
[There was a] French plan to invade Britain in the 18th century
Stink bugs expected to invade W. Va. homes this fall
Invade may be used intransitively:
If they [aliens] invaded I think that they would pacify every part of the planet …
What’ll we do when they invade?
The OED lists a construction that uses on, upon, or into after invade, but doesn’t illustrate the use more recently than 1814.
The construction to invade upon someone’s privacy has the familiar ring of custom, but the construction “invade into” sounds like careless writing.
Here are some examples of the “invade into” construction in which the sentences would be made stronger by dropping the “into.”
Brazilian pepper constantly trying to invade into Corkscrew Swamp Sanctuary
[Should] media invade into celebrities private life or not?
Why can’t Canada sometime try to invade into the USA?
You will learn basic techniques on how to invade into others’ dreams
When computers started to invade into the field of training,
This use of the unnecessary “into” seems to be especially common in medical writing:
individual malignant cells can invade into the stroma
Per cell, more mites invade into shorter and narrower cells
Tumors arising from adjacent organs can also invade into the bladder
the bacterial cells that adhere to and invade into cancer cells. …
cancer occurs when a tumor has the potential to invade into a different tissue
In each of these examples, the word intrude would seem to be a better choice, and one that works comfortably with “into.”
I suppose that a writer might see some stylistic reason for adding the “into” after invade, but in most cases, invade is all you need.