We had a very mild winter and most insects and disease that affect your landscaping, usually suppressed naturally by long periods of cold, will be present this season if your plantings had issues last season. Bagworm is one insect that can be especially devastating to evergreen plantings in particular. Inspect your Arborvitae, Juniper and spruce for evidence of this pest prior to the warm weather arriving when eggs hatch. Hand pick the visible sacks and dispose before chemical control is required. Bagworm eggs typically hatch between May and June, but can be sooner.
Make certain to visually inspect the trees where you removed the Bagworm. Sometimes you may miss one or two sacks inside the canopy and it doesn’t take many sacks filled with eggs to hatch and produce a new generation. Again, this would take place typically from May to June (depending on average daytime temperature) and should you notice activity – smaller versions of the large dormant sacks from the winter – it would be best to treat with an insecticide product at this time.
When using a pesticide product – always wear gloves and safety glasses, but more importantly always follow the manufacturer’s label for specific rates and sensitivity different species of plant.