Beneficial Insects are Important to the Health of Your Herb Garden
Learn to properly identify beneficial insects so you will recognize them in your herb garden environment. Many naturally occurring predators, parasites and unwanted pests are found in herb gardens. In your balanced herb garden environment various beneficial insects help keep the damaging pests under control without the excess use of toxic and damaging pesticides. A small number of pests in the garden will encourage beneficial garden insects to stay and multiply. Learn to identify the valuable insects that will benefit your herb garden environment, from the garden pest insects, to help your herb garden thrive.
Assassin Bug – Reduviidaye
The assassin bug feeds mainly on aphids, caterpillars, Colorado potato beetles, Japanese beetles, leafhoppers, and Mexican bean beetles. They use the long rostrum to inject lethal saliva that liquefies the insides of the prey, which are then sucked out.
The legs of some of these bugs are covered with tiny hairs that serve to make them sticky to help hold onto their prey while they feed. The saliva is commonly effective at killing substantially larger prey than the bug itself. As nymphs, some species will cover and camouflage themselves with debris, or the remains of dead prey insects.
Damsel bug – Nabidae
Damsel Bugs are soft-bodied, winged terrestrial predators. They are considered helpful species in agriculture because of their predation on many types of crop pests, such as cabbage worms, aphids, and lygus bugs. They and other genera are most numerous in fields of legumes such as alfalfa, but they can be found in many other crops and in non-cultivated areas.
They are yellow to tan in color and have large, bulbous eyes and stilt like legs. They are generalist predators, catching almost any insect smaller than themselves, and cannibalizing each other when no other food is available. The damsel bug feeds on aphids, leafhoppers, mites, and caterpillars.
Big-eyed bug – Lygaeidae
Big-eyed bugs are considered an important predator in many agricultural systems and feed on mites, insect eggs, aphids, caterpillar eggs and larvae, immature bugs, leafhoppers, spider mites, pink bollworm, cabbage loopers and whiteflies.
Adult Big-eyed bugs are small black, gray, or tan with proportionately large eyes. Big-eyed Bug’s effectiveness as predators is not well understood; studies have shown that nymphs can eat as many as 1600 spider mites before reaching adulthood, while adults have been reported consuming as many as 80 mites per day.
Predacious Stink Bug – Pentatomidae
If disturbed, stink bugs emit a pungent liquid containing cyanide compounds with a rancid almond scent. Their bodies are usually shield-shaped.
Stink bugs are considered highly beneficial. It is a predator of other insects, especially Mexican bean beetles, Japanese beetles, potato beetles and various caterpillar larvae.
Lady beetle - Hippodamia convergens
The lady bug, commonly known as the convergent lady beetle, is one of the most common lady beetles in North America and is found throughout the continent. The adult lady bug feeds mainly on aphids and other soft-bodied insects, such as mealy bugs and spider mites.
Adults and larvae prey on cotton, pea, melon, cabbage, potato, green peach, and corn leaf aphids. If aphids are scarce, beetles and larvae may feed on small insect larvae, insect eggs, mites and, occasionally, nectar, and honeydew secreted by aphids and other sucking insects. Convergent lady beetles have been recorded as predators of asparagus beetle eggs and larvae and potato psyllids.
Chrysopa are mainly predatory with mites, aphids and other small arthropods on the menu. The bodies are usually bright green to greenish-brown, and the compound eyes are golden in many species. The wings are usually translucent with a slight iridescence; some have green wing veins or a cloudy brownish wing pattern. The name "stink flies", used chiefly for Chrysopa species refers to their ability to release a vile smell when handled.
The eggs are deposited at night, singly or in small groups, and sit atop a short, slender stalk. One female produces some 100–200 eggs which are placed on plants, especially when aphids are present in numbers. Immediately after hatching, the larvae moult, then descend the stalk to feed. They are voracious predators, attacking most insects of suitable size, especially soft-bodied aphids, caterpillars and other insect larvae, insect eggs, and at high population densities also each other.
Trichogramma Wasp - Trichogrammatidae
The wasps of genus Trichogramma are some of the most widely-studied agents of biological control. Trichogramma wasps are tiny insects that parasitize the eggs of many types of agricultural pest insects.
This tiny wasp attacks eggs of more than 200 pest species, including cutworms, corn borers, corn earworms, armyworms, codling moths, and cabbage moths. Female wasps inject their own eggs into the egg and her larvae consume the embryo and other contents of the egg. They are easy to rear and release in fields suffering from pest outbreaks. Release time is critical for their effectiveness since they only attack pest eggs.
Encarsia formosa - encyrtidae
Encarsia has been used as a natural pesticide to control whitefly populations in greenhouses since the 1920s. Use of the insect fell out of fashion due to the increased prevalence of chemical pesticides and was essentially non-existent by the 1940s. Since the 1970s Encarsia has seen something of a revival, with renewed usage in European and Russian greenhouses.
Females deposit 50-100 eggs individually inside the bodies of nymphs or pupae of the host species. The wasp larvae develop in about two weeks at optimum temperatures. Parasitized greenhouse whitefly pupae turn black in about 10 days, while parasitized sweet potato whiteflies turn amber brown. Wasp pupation occurs within the whitefly body. Adult wasps emerge about 10 days later.
It is very important to learn the skill of beneficial insect identification. Your herb garden will thrive with the help of some of the above beneficial insects.