Query bindings keep unwanted quotes around IS NULL

Hmm, CI throws this error:

Code:

A Database Error Occurred

Error Number: 1064

You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near ''IS NULL' AND plantauth.contributor_id IS NULL ORDER BY 'plantitems.id ASC' at line 4

SELECT * FROM plantitems LEFT JOIN plantauth ON plantitems.id = plantauth.plantid WHERE plantauth.owner_id = '51' AND plantitems.death 'IS NULL' AND plantauth.contributor_id IS NULL ORDER BY 'plantitems.id ASC'

Filename: models/Logbook_model.php

Line Number: 29

Here's a screenshot of the model.



WANT to pass a variable's text into the query binding but CI is passing the quotes around IS NULL and the SQL query doesnt like that. (Shown in the fourth paragraph of the error).

Am I missing a parameter like 'escape' (if one exists)?