Recognising the good and the bad insects in your garden

1. Aphids

Aphids are small, sap-sucking insects that come in a variety of colours ranging from brown to orange to green. They usually form clusters where they overwhelm the plant’s natural defences while sucking on the sap of the plant. These insects can proliferate quickly, as many of them are born ready to give birth to the next generation. They are especially attracted to cultivated plants and their feeding activity can be very damaging to flowers and fruits, as well as spread plant diseases. You may notice sticky residue and bits of white fluff on your plants, especially on or near young leaves and flower buds, before you notice the aphids themselves. You can identify aphids by their tiny pear-shaped bodies, long antennae and two short tubes that project from their hind end. The nymphs look remarkably similar to adults and most are wingless, but you will occasionally see winged adults when populations become crowded.

2. Mealy bugs

Mealy bugs are small and white and produce a powdery wax layer that gives them a “fluffy” appearance. You will find them feeding on the plant sap on stems, under leaves and in crevices, visible as white spots or like snow covering parts of your plant. Like aphids, these insects tend to congregate and proliferate quickly and can also be a vector for plant diseases.

3. Scale insects

Scale insects are also like aphids and mealy bugs in that they form groups while feeding on plants. They derive their name from their barnacle-like appearance on host plants, appearing as brown, black, or red bumps on the plant and often have no other discernible features. Many of them are small, blending into the colour of the plant stem, making them difficult to spot. Another thing to look out for with aphids, mealy bugs and scale insects is the honeydew that they excrete which will make your plants feel sticky. Ants are attracted to the honeydew and will often tend these insects and even help to spread them. This sticky residue can also lead to sooty mold or other fungal growth on your plant.

4. Caterpillars

Caterpillars, when occurring singly in or around a plant, are often not a problem. And if you get rid of all of the caterpillars, you are getting rid of the butterflies and moths that the caterpillars later turn into. However, certain caterpillars such as the cabbage looper and the tomato hornworm can be devastating to the plant. Things to look out for include feeding damage in the middle and the edges of plants leaves, little balls of hard dirt or poop, called frass, around the plant and of course the caterpillars themselves. Keep an eye on your non-native, cultivated or food-crop plants as they are especially vulnerable to caterpillars. They do not have the natural defences of native plants. The caterpillars will often hide away, inside leaves, stems or underground during the day so they are not often visible.

5. Stink bugs

Stink bugs are generally large insects with a characteristic shield shape and straight antennae. Stink bugs are common, and having the occasional stink bug in your garden is not a cause for concern. However, in high numbers these bugs can cause damage to leaves, stems and the surface of fruits and vegetables. The damage appears as dimpling or pin pricks surrounded by a yellow or green colour. Stink bugs also emit an unpleasant odour when disturbed or handled and the chemicals can be an irritant if they get on your skin.

1. Praying mantises

Praying mantises are distinctive with their v-shaped heads and their forelimbs held in the prayer position. Although they are often well camouflaged and can be hard to spot, these feisty little insects are efficient predators and will help keep your other insect inhabitants in your garden in check.

2. Lady bugs

Another helpful insect to have in your garden is a ladybug. These attractive beetles are often red or orange with black spots and a black and white head. They are also highly effective predators and feed on pests like aphids and mealy bugs. As larvae they look a bit like a flat black and grey worm with six legs, sometimes with orange or red markings and spikes or nodules along on its sides. These little bugs do not bite or sting and they are very good at munching away at aphids and mealy bugs.

3. Wasps

You might be surprised to see these on the list, as they usually inspire fear in anyone who see them zipping by, however, most wasps are rarely aggressive and many of them are effective predators or are parasitic to pests in your garden. Wasps will go around paralyzing and collecting caterpillars, spiders and other critters to feed to their larvae in their nests, or simply lay their eggs directly into their hosts. This will also help to keep your garden pest numbers at low levels. However, keep an eye out for the larger wasps or hornets with social nests and report them to a local authority for removal if you feel they are a potential danger to you, your family or your pets.

4. Lacewings

These are small, fragile green insects with lovely lacy green wings that they hold over their abdomens and golden eyes. The adults feed mostly on nectar, pollen and honeydew, but their larvae are excellent predators and are big fans of chowing down on aphids and mealy bugs. The larvae are small and light brown in colour with large pincer like mouth parts, but sometimes the larvae will cover themselves in bits and pieces of other insects for camouflage. Lacewing insect eggs are small and very difficult to spot but are distinctive in that the females lay them on tiny white hair-like stalks that suspend the eggs above or below the surface that they are attached to, usually a leaf or plant stem. They are also often laid in a row.

5. Dragonflies

Dragonflies are one of the oldest groups of insects and one of the first to take to the skies. Millions of years ago these aerial predators used their impressive wingspans and powerful flight muscles to dominate the sky and swoop up any meal they could fit in their jaws. Today these aerial predators are smaller but no less terrifying to unsuspecting insects and they are very effective at keeping insect numbers under control near your ponds and dams.