Australian populations of onion thrips, Thrips tabaci Lindeman (Thysanoptera: Thripidae), are resistant to some insecticides used for their control

Abstract

Onion thrips, Thrips tabaci Lindeman, is a major pest of Australian field onion Allium cepa Linnaeus with their control heavily reliant on a few insecticides. An earlier study after grower complaints of control failures did not detect resistance in three populations. After testing an additional nine populations via a Potter spray tower laboratory bioassay unequally against a-cypermethrin, diazinon, dimethoate, l-cyhalothrin, malathion and methidathion, we document resistance in T. tabaci for the first time in Australia. The maximum difference in response (resistance) for each insecticide was detected by dividing the most resistant LC50 response by the least resistant LC50 response. Comparison of the most susceptible to the least susceptible population tested produced a-cypermethrin and l-cyhalothrin resistance at 164-and 606-fold, respectively. Diazinon and dimethoate resistance was also detected at 27-fold and 5.2-fold respectively although omethoate, malathion and methidathion resistance were not detected.

Onion Thrips (Thysanoptera: Thripidae): A Global Pest of Increasing Concern in Onion

“…In addition, some populations of T. tabaci have developed resistance to insecticides in several parts of the world (Martin et al 2003;Shelton et al 2003Shelton et al , 2006MacIntyre Allen et al 2005b;Herron et al 2008;Morishita 2008). Other studies have investigated the potential of other methods of control (biological control, host plant resistance, physical/mechanical control, and cultural practices) to reduce or contain populations of T. tabaci.…”

“…Another pyrethroid, -cyhalothrin, was registered in 1996 and many growers used it exclusively during 1997 and 1998. Some populations of T. tabaci in onion growing areas have developed resistance to pyrethroid and organophosphate insecticides in New York , New Zealand (Martin et al 2003), Canada (MacIntyre Allen et al 2005b), Australia (Herron et al 2008), and Japan (Morishita 2008).…”

Evaluation of Onion Cultivars for Resistance to Onion Thrips (Thysanoptera: Thripidae) and Iris Yellow Spot Virus

“…First, T. tabaci is difÞcult to control because insects are found mainly in the narrow spaces between the inner leaves (Shelton et al 1987) where coverage with conventional foliar-applied insecticides is difÞcult. Second, some populations of T. tabaci have developed resistance to pyrethroid and organophosphate insecticides in New York (Shelton et al 2003(Shelton et al , 2006 and Canada (MacIntyre Allen et al 2005), as well as many other regions of the world (Martin et al 2003, Herron et al 2008, Morishita 2008.…”

Cypermethrin resistance and reproductive types in onion thrips, <i>Thrips tabaci</i> (Thysanoptera: Thripidae)

“…[4][5][6][7][8] The mechanisms of pyrethroid resistance have been characterized in many insect pests including T. tabaci. Nerve insensitivity associated with amino acid mutations in the sodium channel is known as a major mechanism of pyrethroid resistance.…”