Are these hurt by frost or bit by insect?
where are you
when did it happen ...
is it a recent transplant?? .. how have you been watering it.. if so???
i doubt its an insect ...
did it show after the lawn was sprayed???
I am in zone 5. It happened last fall and came back this spring.
its a deciduous plant.. it lost its leaves for winter..
i dont understand.. how you way it happened last fall ... and came back this spring ...
it recurred on new leaves ...???
see ???s above ...
Yes, it recurred on new leaves.
What should I do to heal them?
Thank you, Ken.
It is a new developed area, They are planted two years ago. It grew well and had beautiful leaves in the first year.
there are sprinkle system there. twice/day
An automated sprinkler system? How long is it on for?
Given that information, I'd guess the issue was lack of water. Euonymus alatus often responds to dry soil conditions with a browning or drying of the foliage. Typically, automated watering systems are not set or programmed for the best growth of the plants they are tending. Coming on daily or even twice a day for a few minutes at a time simply does not deliver the volume of water most plants need nor deeply enough to be effective. It will always be better to water less often but for a longer period of time so that the water penetrates deeply down to at least the base of the rootball. Depending on the situation, that might be once or twice a week for 20-30 minutes.
Personally, I think most automated watering systems are a huge waste of money and natural resources for anything other than lawns. They do not deliver the water efficiently, they are rarely programmed properly and they waste huge amounts of water to evaporation and/or run-off. Using a low emission system like a drip or soaker hose is a much better choice.