Not all bugs are pests. In fact, some of them are helpful in our gardens. One of the best ways of pest control is the natural way – by attracting their native enemies. Many growers recognise the help beneficial animals provide as well as the damage done by pests. Another important factor is the potential harm pesticides or insecticides may pose to vegetable gardens. One of the many reasons why being informed about which insect can be used against what pest problem, is valuable knowledge for gardeners looking to avoid the usage of chemical sprays, dusts and other poisons.
“When we kill off the natural enemies of a pest, we inherit their work.”– C.B Huffaker
The Coccinellidae are a family of small beetles, differentiating in sizes, colours and spots. They are usually referred to as ladybugs, ladybeetles or ladybirds. Not all of them are red with black dots and not all are beneficial. The common ladybird (Coccinella magnifica) is red with seven black dots. Both the adult and larvae ladybug are predators, known for their diet of aphids and many other pests such as soft-scale insects, spider mites, mealybugs, and the eggs of numerous others. Bear in mind that if the ladybeetle has nothing to eat, they might flee. The ladybug larvae are actually more reliable than the adult beetle, because they eat much more due to their constant development and are much less likely to flee.
Dragonflies are major predators of mosquitoes and other small insects like flies, bees, ants, wasps and very rarely butterflies. They are usually found around lakes, ponds, streams, marshes and wetlands because their larvae, known as “nymphs”, are aquatic. They are among the fastest flying insects in the world. If there’s been spraying for mosquitoes in your area, chances are it probably also killed off the dragonfly population. If you want to re-introduce these insects in your garden you can do so by planting some reedy plants, having a water source in your garden or you can order them online.
Green lacewings are delicate insects with translucent wings and bright green to greenish-brown bodies. Adults are nocturnal, meaning they are active at night. They are often called “stinkflies” because of the vile smell they release when handled. They feed on pollen, nectar, honeydew supplemented with mites, aphids and other small arthropods. Some, namely the Chrysopa species, are mainly predatory. The lacewing larvae are most predatory, their targets include aphids, white fly, leafhoppers, mites, mealy-bugs, scale insects and some moths and caterpillars. These insects, native to Australia, now found worldwide, can be bought from any bug suppliers. They can be attracted by flowering plants, due to their craving for nectar. Having a variety of plants guarantees a variety of bugs.
The parasitic wasps are divided into some dozens of families. They are parasitoids of various animals, mainly other insects. Many of them are beneficial because they control populations of agricultural pests. But there are also species that are hyperparasitoids, attacking beneficial parasitoids.
In the case of parasitoid wasps, the larvae is the actual predator.
For instance, the Trichogramma wasp is the natural enemy of moth species Lepidoptera. The parasitoid wasp lays eggs inside the larger eggs of Lepidoptera, feeding on the moth’s eggs. Eventually instead of a moth, out of the cocoon emerges a Trichogramma wasp. The parasitoid wasps are not limited to invading eggs, they can also inject their eggs directly into live hosts, such as a caterpillar or pest worm. The adult wasp feeds on pollen and nectar, thus having flowering plants in your garden will attract them.
Other insects that fall prey to these wasps include tomato hornworm, cabbage worm, corn earworm and borer, armyworm, aphids, leaf roller, codling moth and various other caterpillars and grubs.
Usually, you can purchase Trichogramma wasp and a few other species parasitoid wasps from your local supplier.
Spiders are not actually insects. They belong to a group arthropods called Arachnids. Insects have six legs and spiders have eight legs. Most spiders are venomous, but harmless to humans except the black widow and the brown recluse. They usually do not feed on humans.
Spiders are also very helpful predators in the garden. Their diet consists of cicadas, aphids, caterpillars, cucumber beetles, flies, grasshoppers, leafhoppers, plant bugs and thrips. There are approximately 600 different species of spiders in the United Kingdom and almost half of them less than 3mm long.
You can encourage spiders to stay in your garden by planting flowers, tall plants, (sunflowers, cornstalks, and the like, on which to attach their webs) and cover crops.
Woodlice, also known as pill bug or roly-poly, exist in wide range of habitats and have been able to colonise some of the most extreme environments including deserts in Israel and North Africa.
Members of the class Crustacae, which includes crabs, shrimps and lobsters. They are one of the few in their family, that are not aquatic and evolved to live on land. They have a shell-like exoskeleton which they must shed while they grow.
Woodlice are nocturnal and are detritivores, feeding mostly on dead plant matter. Their role in the ecosystem is to produce compost and overturn the soil. However, it’s been established that if their population grows large in numbers, they might attack living plants such as strawberries and tender seedlings.
Pill bugs can also invade homes in search of moisture, hence their presence might indicate a dampness problem. Nonetheless, they are not considered pests because they do not spread disease and do not damage wood or structure.
Frogs and Toads
Frogs and their dry-land relatives, toads, are a large and diverse group of carnivorous semi-aquatic amphibians that inhabit every continent of the world, except Antarctica. They feast on pest insects including mosquitoes, flies, moths, caterpillars and slugs. They can consume up to 10,000 insects in just one summer.
Not only are they beneficial for farms and gardens across the world, but are also living bio-indicators. Frogs are especially susceptible to environmental disturbances, thus making them accurate indicators of environmental stress. In consequence, their populations have been declining worldwide at unprecedented rate.
You can encourage amphibians’ presence in your garden by creating a pond or just small pools of water, such as bird baths. Plant and promote the growth of as many different types of aquatic plants as you can.