Planthoppers are a diverse group of insects, encompassing over 12,500 described species found across the globe. These small, sap-sucking insects are commonly encountered in gardens and various natural landscapes. Their name stems from their ability to “hop” suddenly for quick movement, similar to grasshoppers, though they generally move quite slowly otherwise.
Identifying Planthoppers
Planthoppers possess a small, wedge-shaped body with wings held in a tent-like fashion over their back, often camouflaged to resemble parts of their plant environment. Their antennae are attached below their eyes on the sides of their head, with the two basal segments being thick and bulbous. When disturbed, these insects will often leap away with an impressive jump.
Other types of hoppers include leafhoppers, which are generally slender with a more parallel-sided body and possess small spines on their hind tibiae. Froghoppers, also known as spittlebugs, are recognized by their nymphs that create a frothy, bubble-like mass on plant stems for concealment. Treehoppers are notable for an enlarged, often bizarrely shaped, shield-like part behind their head, called the pronotum, which can mimic thorns or other plant structures.
Impact on Plant Health
Planthoppers feed by piercing plant tissues with their specialized mouthparts and extracting sap from the phloem. This feeding may manifest as tiny white spots, or stippling, on the upper surface of leaves. Prolonged feeding can lead to yellowing or browning of leaf margins, leaf curling, and stunted plant growth. Severe infestations can result in “hopper burn,” where entire plant patches yellow, brown, and dry out, potentially leading to complete crop loss.
Beyond direct feeding damage, planthoppers cause indirect harm. As they feed, they excrete a sugary waste product called “honeydew,” which makes plant surfaces sticky. This honeydew promotes the growth of black sooty mold, a fungus that covers leaves and stems, reducing photosynthesis and weakening the plant. Additionally, certain planthopper species can transmit plant viruses and diseases, such as rice ragged stunt and grassy stunt diseases, which compromise plant health and cannot be cured.
Management and Control Strategies
Managing planthopper populations often begins with simple, environmentally conscious methods. A strong spray of water from a garden hose can physically dislodge planthoppers from plants. This method is effective for smaller infestations or as a first line of defense.
Encouraging natural predators helps keep planthopper numbers in check. Ladybugs, lacewings, and parasitic wasps prey on planthoppers and their nymphs. Promoting a diverse garden ecosystem attracts these beneficial insects, contributing to biological control.
For more persistent issues, low-impact treatments can be applied. Insecticidal soaps work by disrupting the cell membranes of soft-bodied insects upon direct contact, leading to dehydration. Horticultural oils, including petroleum-based or neem oil varieties, suffocate insects by coating their bodies. Both products are most effective when applied directly to the insects and have little residual activity once dried, minimizing harm to beneficial insects.
Chemical insecticides are a last resort for severe infestations on ornamental plants. When using these products, follow all label instructions to ensure proper application and to minimize impact on non-target organisms and the environment. Targeting applications to immature planthoppers, which are often less mobile and more susceptible, can improve effectiveness.