There are plants that repel insects.
I don’t think “repelar” should be in the subjunctive here. This is a statement of fact. It would be subunctive if it were a question (¿Hay plantas que repelen…?) or a negation (No hay plantas que repelen…)
It’s not in the subjunctive mood. The verb is repeler.
Thanks, & you’re right; I was thinking of repelar, which of course means something quite different. But the cause of my confusion was, I’m almost certain, that repelar was the infinitive that was provided in the pop-up window when I selected “repele.” So that needs fixing.