Patterns of Insecticide Resistance in Onion Thrips (Thysanoptera: Thripidae) in Onion Fields in New York

Abstract

To develop an insecticide resistance management program for onion thrips, Thrips tabaci Lindeman (Thysanoptera: Thripidae), on onions (Allium spp.), we surveyed populations in commercial onion fields in New York and evaluated their susceptibility to the two most widely used classes of insecticides plus two new insecticides during 2003-2005. All insecticide evaluations were conducted using the Thrips Insecticide Bioassay System (TIBS). As in our surveys conducted during 2002-2003, there were large temporal and spatial variations in susceptibility to the pyrethroid lambda-cyhalothrin (Warrior) across onion-growing regions in 2003. New data indicate that the field rate of methomyl (Lannate LV) still provides control but that the genes for resistance to methomyl are present in some populations. Tests with the two new insecticides, acetamiprid (Assail 70 WP) and spinosad (SpinTor 2CS), indicated they provided > 85% mortality at the field rate. To determine the spatial variation in insecticide susceptibility within a region, a series of systematic assays were conducted with lambda-cyhalothrin and methomyl. In 2004 and 2005, our data indicated that the within-region spatial variation in susceptibility to lambda-cyhalothrin was not large at the field rate or for the 100 ppm rate of methomyl. In 2005, a year in which T. tabaci densities in most fields were much higher than in 2004, growers were unable to control T. tabaci in particular fields and attributed this lack of control to resistance. Yet, we found similar levels of high susceptibility in all fields when using TIBS. This finding suggests that resistance had not developed and that variation in control may have been due to other factors, such as localized higher populations, poor spray coverage, too much time between spray applications, or different onion varieties.

Identification of an alternative knockdown resistance (kdr)-like mutation, M918L, and a novel mutation, V1010A, in theThrips tabacivoltage-gated sodium channel gene

“…In addition, we have identified two non-synonymous point mutations in a region of the T. tabaci sodium channel gene which is known to confer pyrethroid resistance to T. tabaci and other insect species. 26 These are methionine to leucine at position 918 (M918L) and valine to alanine at position 1010 (V1010A). In a recent report on identification of target site insensitivity alleles of the sodium channel gene, Toda and Morishita 23 found three non-synonymous mutations M918T, T929I, and L1014F which are expected to be responsible for the high resistance of Japanese populations of T. tabaci to pyrethroid insecticides.…”

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.…”

Relationships between insect predator populations and their prey, Thrips tabaci, in onion fields grown in large-scale and small-scale cropping systems

“…Conventional control of T. tabaci has relied on multiple applications of insecticides (Shelton et al 2006;Nault and Shelton 2010). Recently, novel selective insecticides co-applied with penetrating surfactants have been shown to improve T. tabaci control (Nault et al 2013) and reduce the number of applications needed to protect the crop during the season (Nault and Shelton 2010).…”