I am container gardening on my balcony and the leaves of my morning glory vines are starting off green but slowly mottling to yellow. I’ve been using a standard pesticide.
Generally, when leaves turn yellow it’s a sign of either under- or over-watering, and I suspect it may be the latter. Morning glories love soil to be on the dry side and require very little fertilizer once they are established. Water only when the top inch of the soil is dry. Also, check to see that the soil is draining well. Your container should have holes in the bottom to prevent the soil from becoming boggy. Morning glories are tropical plants and as such they like lots of sun, so be sure they’re receiving enough exposure to light. They are rarely bothered by pests or disease, so you can stop using the pesticide.