It is found in the US, Canada, Europe, Asia, and was just discovered in Australia in 1993. The Western Flower Thrips feeds on almost any flowering plant, and is extremely hard to control due to its small size and preferred feeding and breeding location on the host plants. Below is the discussion on life cycle, new thrips strains, infested and infected plant symptoms, and controls for the insect. Lifecycle and Identification You can identify a Western Flower Thrips by the number of setae on the pronotum, number of pairs of setae between compound eyes and simple eyes on the head, and the presence of two rows of setae on the wings. The Western Flower Thrips is about 1mm long and ranges in color from yellow to dark brown.
Females are larger in size and rounder, whereas, males are paler in color with narrower abdomen.
Eggs are laid into the plant tissue with only the top part visible. The temperature dictates how long a thrips is a certain cycle, but generally they can go from three to twelve days. The Western Flower Thrips has two larval instar stages. At this point the insect can become infected with viruses that they can only transmit in the adult phase. Towards the end of the second instar stage the larva starts to move down the plant to soil and leaf litter down below.