I recently bought a Pink mandevilla (alice du pont). Its about a feet tall. One fine day I planted the mandevilla in our backyard. It has been over a week since I planted it.

Couple of days back I noticed brown patches on the older/bigger leaves. At first the brown patches appeared on the bottom leaves. Today I noticed that the brown patches are spreading to the other leaves as well. The brown patches look like sun burnt leaves.

At this point, I'm really not sure why these brown patches are appearing on the leaves. I really don't want the plant to die on me. Are these brown patches because of bugs? If so what care needs te taken? Please suggest! I water the plant once in the morning and once in the evening. I make sure the soil is wet.

Please suggest!