Pest Lifestyles: Piercing and Sucking Bug

 The insect damage most frequently found on interiorscape plants comes from piercing and sucking pests. To understand why these pesky critters find our plants to be so attractive, let’s examine the environment they thrive in and what they look for when they’re hungry.

Sap Suckers

Aphids, scale, mealybug, whitefly and spider mites all have modified mouth  parts called stylets that pierce plant tissue and extract fluids for nourishment. The flexible stylets can pass through fibrous tissue to tap into the plant’s phloem or vascular bundles. The mite or insect extracts protein, minerals and vitamins from the plant sap. The remaining fluid (called honeydew) is excreted by the pest.

Finding the Perfect Home

Insects do not feed and reproduce indiscriminately on all plants. The host plant they choose must fulfill the insect or mite’s requirements for suitable food and shelter.

To select a host plant, insects and mites respond to various stimuli from the surrounding environment, the plant and the pest’s own unique needs. For example, insects have been known to react to colors, shapes and smells in the environment. Aphids and whitefly seem to be attracted to yellowish colors. Thus the pale green color of new growth or the yellowish-green foliage of a stressed plant is more attractive to these insects than a dark green leaf.

The physical make-up of the insect also determines were tired pest will call “home”. Insects with small or weak stylets may not be able to penetrate woody stems or leaves with a thick epidermis or excess cutin, and will not be attracted to plants with these characteristics. Cilia on leaves may prevent insects or mites with short stylets from damaging leaf tissue. Other insects may find the sap of the potential host plant undigestible or toxic and will stay away.

Soft-bodied insects such as mealybug dehydrate in direct sun or high temperatures. They are attracted to plants that provide
shelter from the environment. They protect themselves by hiding in plant crevices and covering themselves with a white cottony wax. Mealybugs migrate out into the open only after the population has increased and all the available crevices are filled. Spider mites start on the underside of leaves and migrate to other areas as the population increases and available food supplies diminish.

The Ideal Environment

Piercing and sucking insects and mites prefer similar environments. High temperatures and low humidity breed insects and mites at an alarming rate. Normally these pests go through a resting phase called diapause during the cool temperatures and short days of fall and winter; but, the warm temperatures in the interiorscape keep them active all year long.

A plant stressed from improper envirorunental conditions or poor maintenance is very susceptible to infestations. Like a sickly person who catches every illness in the book, a plant weakened by improper care declines quickly from a pest invasion and has a difficult time recovering. Scale, mealybug, mites, aphids and whiteflies thrive on plants with excess levels of nitrogen, improperly maintained plants or plants weakened from incorrect light, temperature or humidity levels.

Knowing the lifestyles and habitats of our most persistent pests helps us control and eradicate.