Difference between pests and insects

Published 6:21 pm Saturday, August 25, 2018

By Terry Rector

In our human effort to keep things simple, quite a few pests are miscalled.  We like to categorize pests as insects, weeds and diseases, while also acknowledging mice and armadillos as potential pests.

After we have exhausted known pest preventions like mothballs, crop rotation and window screens, we like to simply decide if a manmade or organic insecticide, herbicide, or fungicide is needed.  I’m all for simple, even when it requires a slight exaggeration of fact.

Email newsletter signup

Sign up for The Vicksburg Post's free newsletters

Check which newsletters you would like to receive
  • Vicksburg News: Sent daily at 5 am
  • Vicksburg Sports: Sent daily at 10 am
  • Vicksburg Living: Sent on 15th of each month

Let’s begin with plant insect pests; some are not insects.  We lump ticks and spiders and mites in with insects. These Arachnids have eight legs, two body segments and no antennae or wings.  But they are certainly more like insects than weeds or fungi.  Plus the same stuff that will repel or kill insects will work on most of them.

Actually, of the “non-insect insects” only a few of the mite species are true plant pests, sucking juice from leaves and stems. Spiders and ticks are not threats to plant health.

Millipedes and centipedes also get tossed in with the insect group. They are not insects and they also don’t pose a threat to plants.  They don’t feed on anything important to us.

Centipedes are carnivorous, consuming insects, mites, spiders and one another. Centipedes do use venom to paralyze their dinner victims and I’ve read about a six-inch species that lives somewhere nowhere near us that can inflict a painful bite on people.

Millipedes’ diets fit in nicely with recycling since they eat mostly decaying plant matter, but nothing alive. Centipedes and millipedes are only considered pests because we don’t want them to come indoors after migrating by the hundreds across the parking lot.

Microscopic nematodes are listed with diseases by university plant people even though nematodes are true animals, worms to be exact.

The most common one that threatens vegetables and ornamentals, the root knot nematode, is often the unidentified cause of plants yellowing and wilting away as the invisible worms travel within roots, eating and laying piles of eggs. This is the pest problem that can be helped by planting marigolds, but only the soil adjacent to the marigolds’ root zone is protected. A few scattered marigolds in a garden won’t help.

Algae pests of various types get categorized based on where they grow.  If they grow on brick walls or sidewalks, we typically list them with diseases.  And if they must go, there are lots of remedy cleanser combinations for scrubbing away algae as well as chemical fungicide recommendations.

As with most pest removal methods, the algaecides are “for the time being.” Whatever moisture-shade-temperature combo attracted whatever algae in the first place will invite it back.

However, if algae is growing in a pond or lake, then it is thought of as an aquatic weed problem possibly in need of an aquatic herbicide for control.

We wish the fish species grass carp would solve all our water vegetation problems, but the carp can’t stand the taste of aquatic filamentous algae.


Terry Rector is spokesman for the Warren County Soil and Water Conservation District.