Aphids come in several colours. If you use plain bar soap dissolved in warm water and put into a clean sprayer (small, quart-size) you can squirt them off. Just plain water will do that, too, but the soap helps remove the ones that miss the shower.

Might be a water issue - if the ground is dry on top any water you put on may be just running off, not soaking in. First move is to gently fork over the ground for at least a foot out from the stem. Break up the surface but not dig deeply.

Then get some warm water and slowly pour it around the plant. About a gallon - and no hotter than feels mild to your inside wrist skin.

Leave it for about 20 minutes, then come back and add another gallon or two.

If you have mulch around your plant it may have been soaking up your watering and stopping it from getting to the roots.

Or, if the ground is damp, or smells musty, there might be too much water. In which case leave off watering until the ground is dry for at least an inch down. Remember that roots need air as well as water, otherwise they can start to rot.

The last possible is fertiliser burn. If you accidentally put in a bit extra on last month's feeding... If you think that may have happened, just add water for this month.

These are 'the most likely'. Otherwise - check with your local garden centre. Other possibles include spray drift, salt damage or wind damage.