Aphids and White Flies

Aphids are oval green, yellow, orange  or black as well as other colors with or without wings.  Aphids cluster on the stems and under leaves. Infested leaves curl and turn yellow; plant is weakened in general. The greatest damage would be after a cold spring. What you can do for control:

LadyBeetles are very effective in controlling aphids so are LAcewings and Praying Mantids. Insecticidal Soap and Horticultural Oils can be utilized when population of aphids are too large for beneficial insects to control.

White Flies  are very small milk white flies. When they are disturbed, the flies flutter about like tiny snowflakes. The cause the leaves to yellow and dry. Black sooty mold grows on honeydew secretions of whiteflies. Leaves also drop early.

Controls would be Lacewings and Praying Mantids. You can also use Insecticidal Soap.

Remember do not water at night. Watering at night will cause fungus which will cause bugs.