Here are a few questions on garden pests, starting with my Japanese holly.
1. Flies are attracted to Holly trees when they are in bloom. Hanging sticky fly traps will somewhat control them, but they will disappear when the bloom is gone.
2. Small wasp killing hydrangea tree. A clear wing sawfly lays eggs on the tree. When the larva hatch they bore into the tree. Over time they will kill the tree. Spraying them with a pyrethryn spray will kill the larva, but you need to spray before they enter the tree. Systemic spray have proven to be ineffective with these borers. The trick is to become familiar with the adult and spray when they are around the tree laying eggs and when the larva hatch.
3. Controlling vegetable leaves and produce from pests. Insecticidal soap, neem and pyrethrins are organic sprays for controlling pests on vegetables. Follow instructions on the labels for effective control of pests. It is best to inspect the plants frequently especially under the leaves and sray accordingly.