Insecticide resistance in onion thrips (Thrips tabaci) (Thysanoptera: Thripidae)

Abstract

Onion thrips from onion (Allium cepa) crops were tested for resistance to four insecticides (deltamethrin, diazinon, dichlorvos, and endosulfan) following reports of failure of insecticides to control onion thrips in the field. Bioassays to determine baseline concentration-mortality responses used thrips from two insecticide susceptible populations. Leaf discs (24 mm diam.) cut from leek (Allium porrum) were dipped in insecticide solutions and placed, when dry, in Petri dishes (50 mm diam.) with ventilated lids. Ten adult female thrips were added, and mortality was recorded after 24 h at 25°C. Five or six concentrations of each insecticide were tested and bioassays were usually repeated 3 times. The lowest concentration, which consistently killed over 90% thrips, was used as a diagnostic concentration to screen thrips populations collected from four onion crops and compared with both susceptible populations using the same bioassay. Each test population was also exposed to leaves dipped in water. One Canterbury and three Auckland populations were resistant to deltamethrin, whereas only the three Auckland populations were resistant to diazinon and dichlorvos. No population was resistant to endosulfan. Concentration-mortality responses were determined for deltamethrin and diazinon. Based on the LC 50 s, one Auckland population was 40 times more resistant to diazinon and the Canterbury population was 550 times more resistant to deltamethrin than susceptible populations. The New Zealand onion industry responded to the initial failure of insecticides by developing and implementing an insecticide resistance management strategy and research to improve onion thrips control.

Thrips Species Composition on Onions in the Vidalia Production Region of Georgia

“…The competition studies conducted with the T. tabaci collected from Peruvian onion cull piles indicate that this species has the potential to successfully compete with the F. fusca under warm conditions (25 °C). However, F. fusca seems to be favored by cool temperatures, as indicated by the negative correlation with winter temperatures in this study, which is characteristic of the Vida- Onion thrips is well known for pyrethroid resistance in much of its range (Martin et al 2003;MacIntyre-Allen et al 2005;Shelton et al 2006), and field trials conducted in the Vidalia region in 2007 verified poor performance against the onion thrips and continued good efficacy against tobacco thrips . Concerns over the potential impact of IYSV led to increased reliance on insecticides for control of the thrips vector in 2006 and 2007 (Sparks, personal observation).…”

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).…”

The efficacy of intercropping with birdsfoot trefoil and summer savoury in reducing damage inflicted by onion thrips (Thrips tabaci, Thysanoptera, Thripidae) on four leek cultivars

“…Thus, they are well protected from the application of insecticides. Several authors have reinforced these concerns by reporting increased resistance to insecticides in onion thrips throughout Europe and various other parts of the world (Theunissen & Schelling 1998, Martin et al 2003, Foster et al 2010. Simultaneously, the number of registered insecticides that can be used to control onion thrips is decreasing.…”