Sucking pests

Introduction • FAQs • Sap-feeding insects • Mesophyll-feeding insects


feeding aphid

A tiny aphid presses its sucking mouthparts against a plant leaf to feed. Inside the visible mouth is an even tinier, set of hypodermic needle-like mouth parts that draw sap from plant veins.

Insects that use special sucking mouth parts to feed on sap and plant cells include some of the most diverse and interesting insects in the garden.  They can also be some of the most destructive pests in home landscapes.  Unlike the beetles and ants with their chewing mouth parts, insects that feed on sap have piercing/sucking mouth parts.  Damage from sap feeders can be difficult to spot at first.  After a while, however, plants being attacked by sap-feeders will take on a shiny look and sticky feel.  Eventually these sticky plants may turn black with a coating of black sooty mold, a type of fungus that grows on the sugars in the drippy droppings of sap-feeders.  Common sap-feeding insects include mealybugs, scale insects, aphids, true bugs and whiteflies.

leafhopper feeding damage to mint

Leafhopper feeding damage to mint. The lighter-colored spots are typical of damage caused by mesophyll-feeding insects and mites.

Not all plant-feeding insects with sucking mouth parts feed on sap.  Some feed on the inner tissues of leaves, called mesophyll (MEEZ oh fill).  Mesophyll includes the food producing (photosynthetic) cells layers of a leaf that lie between the upper and lower epidermis.  Symptoms of mesophyll feeding include a stippled pattern of yellowish, gray or whitish dots on the plant surface.  This damage causes the leaf color to dullen, turn yellow or gray, and eventually brown. Other mesophyll feeders may leave pits or sunken areas of leaves that eventually turn brown and die.  Spider mites, leafhoppers, lace bugs and yucca bugs are examples of mesophyll-feeders common in Texas landscapes.

Frequently Asked Questions

Sap-feeding insects

Mesophyll-feeding insects and mites

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