Planthoppers

Planthoppers or leafhoppers are a sapsucking species that are generally unwelcome in the garden. There are many varieties - bugs, aphids, cicadas, leafhoppers, and scale insects, etc. – and they all belong to the order of Hemiptera. Despite their variety, they all have specialised mouthparts for piercing plant stems and sucking up the sap of the plant. If their numbers are great enough the plant will eventually die.

As they feed, planthoppers leave behind a coating of honeydew on the stem. The honeydew can attract beneficial insects like bees, or it can encourage the growth of sooty mould which damages the plant as well.

Hemiptera have three life stages – egg, nymph, and adult. Beetles, butterflies, and bees for example have four stages – egg, larva, pupa, and adult.

The moth-like Passionvine Hopper, Scolypopa australis, has a wide range of host plants with soft stems, native and exotic, apart from the obvious Passion Vine species. The adults with their transparent wings are typically just 6-7mm long.

The nymph of the Passionvine Hopper looks like a miniature cicada and feeds on the plant in the same way as the adult. They are often covered in tufts of waxy filaments extending from their posteriors giving them their name of fluffy bums. It is assumed that this is to deter predators by proffering them a mouthful of sticky wax.

The adult Green Planthopper, or torpedo bug, Siphanta acuta, has a bright green, flattened, triangular body. It holds it wings shut in a vertical position, resembling a small green leaf or thorn.

Like the Passionvine Hopper, when disturbed, the Green Planthopper springs away and flies off to another nearby plant, its camouflage properties rendering it almost invisible.

At 9-10mm, adult Green Planthoppers are a little larger than Passionvine Hoppers. The nymphs of Green Planthoppers also have waxy tufts extruding from their hindquarters. Both species are native to Australia but are found pretty much world-wide these days.

Many garden pest websites spend a lot of time referencing chemical control of theses sap suckers. It would be nice though if we could rely on natural biological control. For example, some birds and other insects do prey on adult planthoppers, their nymphs, and their eggs. Large infestations can be dealt with by applying a weak soapy water solution.