Why Are My Mandevilla Leaves Getting Speckles?

Question

This my first mandevilla! Things have been going awesome so far this summer, we live downtown Toronto and I grow this guy on our terrace. The plant gets at least 6-8 hrs of sun a day. Last week I found aphids near the top and have sprayed it twice the past week with soapy water. It’s also gotten a lot of water this week! It rained heavily and I’ve been keeping it wet because it’s so tall it tips over. So yesterday I fertilized it for the first time ever and sprayed it the second time with soapy water. This morning I noticed there are brown tiny speckles and I’m wondering if the soap burnt it or if it’s over watered? Or…? Some of the leaves had speckles last week but it suddenly over night has spread to most of the top where it was sprayed for aphids 🙁

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Answer 1

This infection is likely because of the aphids, and overwatering in combination.

From here, a fungicide will be necessary. This article will help:

https://www.gardeningknowhow.com/garden-how-to/info/using-fungicides-in-garden.htm

Here is an article that will help you with the care of the plant:

https://www.gardeningknowhow.com/ornamental/vines/mandevilla/mandevilla-plant.htm