Summer has begun, along with a few problems in the garden. Plants aren’t plastic. They are alive; they thrive or decline according to how well their needs are met. Some are vulnerable to disease; others may be food for other living things. And they rarely remain the same as the day they were purchased.

Is this shocking? New gardeners are often dismayed. Others of us have annual amnesia. In the throes of spring plant lust most of us forget what follows— weeds, watering in hot weather and, yes, some pests.

So we’re surprised yet again. But some facts and practical advice may keep you from tossing out your trowel.

Little green bugs

First, about insects in general: They are essential for life as we know it, critical parts of the ecosystem. They help us as predators, pollinators and soil-builders, and they feed other creatures. Trying to kill them all is wrong, foolish and wasteful.

But what about the devastated leaves on the Heliopsis “Lorraine Sunshine” (and black-eyed Susans, daisies, salvias and herbs)? You see little brown dots, like stippling, that soon coalesce, leaving holes.

The culprit is a true bug, called the four-lined plant bug, that feeds by sucking. That draws out chlorophyll, leading to brown dots. The bug measures less than a quarter inch, named for the lengthwise green and black striping. The nymphs are reddish. Both scoot under the plant leaves, so look quickly.

Solutions? Live with it, as they won’t kill the plants and will be gone in a few weeks. Or, for extensive damage, you could spray insecticidal soaps, the most benign of the labeled pesticides. Spray under the leaves and make a direct hit.

Alternative: Take notes and next year choose plants that aren’t affected.

A powdery coating

This spring has favored some fungus diseases, especially powdery mildew, a grayish white film that covers leaves.

All diseases require specific hosts and precise conditions. Powdery mildew thrives in humid conditions and grows especially well on certain favorite garden plants including bee-balm, phlox, lilacs, ninebark and Pulmonaria.

Improve the situation by placing vulnerable plants in breezy locations, well spaced, and thinning them. Wipe or hose off the mildew on small plants, or choose a fungicidal horticultural oil spray such as Fungus Pharm. Powdery mildew has specific strains that attack specific plant species, so you needn’t worry about the whole garden. Just cut out the ugly parts and, in most cases, it too will pass.

A pest philosophy

Very controlling types won’t like hearing this, but we are not completely in charge in our gardens. We orchestrate. We favor the plants and creatures we like, by how we tend them and manipulate the setting and by encouraging helpful predators. We choose what works and discard what doesn’t. Healthy plants thrive and most problems pass. Just stay out there and keep your baton waving.