Thrips, a mangled abbreviation of the scientific name Thysanoptera, are small insects with fringed wings.(1) Some feed only on mites and other insects, while others target plant life. The most innocuous form of thrips eat only pollen and fungi.
Thrip species often are named for the type of plant that they prefer. Hence, there are avocado thrips, citrus thrips, greenhouse thrips fond of all sorts of perennials, onion thrips, and so on.
Each thrip begins as an egg. Following a pair of active nymphal or feeding larval stages, they progress to a non-feeding prepupal and pupal transition, and then onto full adulthood. Their lifecycle is classified as one that falls somewhere between gradual and complete, and can be completed during favorable warm weather in as little as two weeks.
Thrips eggs are relatively large in relation to the size of the female that lays them. These eggs are usually inserted in plants, and once a thrip reaches prepupal or pupal stage, it will then either lodge into a plant crevice or drop to the soil below. Each year, eight or more generations of thrips can produce.
Hard to Detect
Because thrips are so small and hide in soil or plant crevices, combating them is that much more difficult. Experts in Kenya were warning coffee growers in the summer of 2011 of a possible infestation beginning in August.(2) Thrips thrive in dry weather, so nature’s answer to preventing an August outbreak would be torrents of rain that can wash thrips away off coffee plant leaves.
In U.S. gardens, the rain and to a certain extent other insects help mitigate the thrip threat. Among those feasting within the insect world on common flower thrips for example are ladybird beetles, predatory mites, big-eyed bugs, green lacewing, damsel bugs, and parasitic wasps.(3) In all cases, these thrip eaters can greatly reduce the length of their prey’s lifecycle.
(1) University of California Davis – Thrips, Retrieved July 17, 2011 from http://www.ipm.ucdavis.edu/PMG/PESTNOTES/pn7429.html
(2) Reuters – “Kenya Coffee Agency Warns Thrips Could Hit Crop”, July 1, 2011, Retrieved July 17, 2011 from http://af.reuters.com/article/kenyaNews/idAFLDE76012Y2011070
(3) Florida Times-Union – “Critter of the Month (June): Flower Thrips”, June 25, 2011, Retrieved July 17, 2011 from http://jacksonville.com/entertainment/home-and-garden/2011-06-25/story/critter-month-june-flower-thrips