Matthew 7:17 KJV Even so every good tree bringeth forth good fruit; but a corrupt tree bringeth forth evil fruit.
Cowbane aka northen water hemlock has a yellowish liquid in its root that is very poisonous. A single bite of the root can be sufficient to cause death in a man and 230 gram of the root is sufficient to kill a horse.
- Wikipedia Cicuta virosa , https://en.wikipedia.org/wiki/Cicuta_virosa
Matthew 7:12-20 KJV  Therefore all things whatsoever ye would that men should do to you, do ye even so to them: for this is the law and the prophets.  Enter ye in at the strait gate: for wide is the gate, and broad is the way, that leadeth to destruction, and many there be which go in thereat:  Because strait is the gate, and narrow is the way, which leadeth unto life, and few there be that find it.  Beware of false prophets, which come to you in sheep’s clothing, but inwardly they are ravening wolves.  Ye shall know them by their fruits. Do men gather grapes of thorns, or figs of thistles?  Even so every good tree bringeth forth good fruit; but a corrupt tree bringeth forth evil fruit.  A good tree cannot bring forth evil fruit, neither can a corrupt tree bring forth good fruit.  Every tree that bringeth not forth good fruit is hewn down, and cast into the fire.  Wherefore by their fruits ye shall know them.
Evil fruit thorns and thistles and good fruit figs and grapes .
Those that have evil fruit are corrupt .
Also notice that Jesus says that many take the broad way  indicating that the majority of professing Christians are evil fruit.
I think evil fruit people are false, evil men.
I think evil fruit is both about preaching a false gospel and about doing evil deeds.
3 John 1:9-11 KJV  I wrote unto the church: but Diotrephes, who loveth to have the preeminence among them, receiveth us not.  Wherefore, if I come, I will remember his deeds which he doeth, prating against us with malicious words: and not content therewith, neither doth he himself receive the brethren, and forbiddeth them that would, and casteth them out of the church.  Beloved, follow not that which is evil, but that which is good. He that doeth good is of God: but he that doeth evil hath not seen God.
Those that do evil have not seen God.
How should we then deal with evil fruit.
Job avoided evil.
Job 1:1 KJV There was a man in the land of Uz, whose name was Job; and that man was perfect and upright, and one that feared God, and eschewed evil.
We should avoid it.
Psalms 34:14 KJV Depart from evil, and do good; seek peace, and pursue it.
We should depart from evil.