Patterns of Insecticide Resistance in the Mosquitofish, Gambusia affinis

1969 ◽  
Vol 26 (9) ◽  
pp. 2395-2401 ◽  
Author(s):  
Dudley D. Culley Jr. ◽  
Denzel E. Ferguson

The extent of insecticide resistance in a resistant population of mosquitofish (Gambusia affinis) from Belzoni, Mississippi, was compared with that of a susceptible population from State College, Mississippi, using 28 insecticides of five major groups. Results of 48-hr bioassays show that resistant mosquitofish have developed high resistance only to the toxaphene–endrin related insecticides, even though insecticides from other groups were heavily applied. Spray records for the Belzoni area and insecticide characteristics such as stability and toxicity aided in evaluating cross-resistance patterns in the resistant population. Patterns of resistance in mosquitofish are similar to those in many resistant arthropods.

Plant Disease ◽  
2014 ◽  
Vol 98 (4) ◽  
pp. 532-539 ◽  
Author(s):  
Achour Amiri ◽  
Stacy M. Heath ◽  
Natalia A. Peres

Succinate dehydrogenase inhibitors (SDHIs) constitute a mainstay in management of gray mold caused by Botrytis cinerea in strawberry and several other crops. In this study, we investigated the risks of resistance development to three newer SDHIs (i.e., fluopyram, fluxapyroxad, and penthiopyrad) and their cross-resistance with the previously registered boscalid. We investigated the mutations in the SdhB subunit and evaluated their impact on microbial fitness in field populations of B. cinerea. Amino acid substitutions associated with resistance to SDHIs were detected at three codons of the SdhB subunit (BH272R/Y/L, BP225F, and BN230I) in the succinate dehydrogenase gene of field isolates from Florida. The BH272R, BH272Y, BH272L, BP225F, and BN230I mutations were detected at frequencies of 51.5, 28.0, 0.5, 2.5, and 4%, respectively. Strong cross-resistance patterns were evident between boscalid and fluxapyroxad and penthiopyrad but not with fluopyram, except in BH272L, BP225F, and BN230I mutants. All five mutations conferred moderate to very high resistance to boscalid whereas the BH272Y conferred resistance to fluxapyroxad and penthiopyrad. The BH272L, BN230I, and BP225F mutations conferred high resistance to all four SDHIs tested. Resistance monitoring following the first use of penthiopyrad in strawberry fields in Florida in 2013 suggests potential for quick selection for highly resistant populations and warrants careful use of the newer SDHIs. No evidence of major fitness costs due to the mutations in the SdhB subunit was found, which indicates the potential ability of the mutants to survive and compete with wild-type isolates. Our study suggests high risks for rapid widespread occurrence of B. cinerea populations resistant to the novel SDHIs unless appropriate rotation strategies are implemented immediately upon registration.


Weed Science ◽  
2020 ◽  
Vol 68 (2) ◽  
pp. 116-124 ◽  
Author(s):  
Marcos Yanniccari ◽  
Ramón Gigón

AbstractIn Argentina, Lolium spp. occur in 40% of winter cereal crops from the Pampas. Several years ago, cases of glyphosate-resistant perennial ryegrass (Lolium perenne L.) were detected, and the use of acetyl-CoA carboxylase (ACCase)-inhibiting herbicides to eradicate these plants has been considered. The aim of this study was to evaluate the sensitivity of a putative pinoxaden-resistant L. perenne population to ACCase-inhibiting herbicides. Around 80% of plants from the putative resistant population survived at a recommended dose of pinoxaden, and they produced viable seeds. The resistance indices (RIs) to pinoxaden were 5.1 and 2.8 for plant survival and seed production, respectively. A single point mutation that conferred a Asp-2078-Gly substitution in ACCase was the source of the resistance. To match the plant control achieved in the susceptible population, the resistant population required 5.4- and 10.4-fold greater doses of clethodim and quizalofop, respectively. RIs for viable seed production when treated with clethodim and quizalofop were 3.3 and 6.6, respectively. The Asp-2078-Gly mutation endowed significant levels of resistance to pinoxaden, clethodim, and quizalofop. For three herbicides, the level of resistance of a pinoxaden-resistant L. perenne population to ACCase inhibitors was evaluated, based on an evaluation of dose response for plant survival and seed production. The RIs were higher for plant survival than for seed production. In Argentina, the selection pressure associated with clethodim and haloxifop preplant application and pinoxaden use on wheat (Triticum aestivum L.) and barley (Hordeum vulgare L.) crops, would have favored the propagation of the Asp-2078-Gly mutation with its associated resistance.


Weed Science ◽  
2015 ◽  
Vol 63 (4) ◽  
pp. 946-953 ◽  
Author(s):  
Rupinder Kaur Saini ◽  
Jenna Malone ◽  
Christopher Preston ◽  
Gurjeet Gill

Clethodim resistance was identified in 12 rigid ryegrass populations from winter cropping regions in four different states of Australia. Clethodim had failed to provide effective control of these populations in the field and resistance was suspected. Dose–response experiments confirmed resistance to clethodim and butroxydim in all populations. During 2012, the LD50of resistant populations ranged from 10.2 to 89.3 g ha−1, making them 3 to 34–fold more resistant to clethodim than the susceptible population. Similarly, GR50of resistant population varied from 8 to 37.1 g ha−1, which is 3 to 13.9–fold higher than the susceptible population. In 2013, clethodim-resistant populations were 7.8 to 35.3–fold more resistant to clethodim than the susceptible population. The higher resistance factor in 2013, especially in moderately resistant populations, could have been associated with lower ambient temperatures during the winter of 2013. These resistant populations had also evolved cross-resistance to butroxydim. The resistant populations required 1.3 to 6.6–fold higher butroxydim dose to achieve 50% mortality and 3 to 27–fold more butroxydim for 50% biomass reduction compared to the standard susceptible population. Sequencing of the target-site ACCase gene identified five known ACCase substitutions (isoleucine-1781-leucine, isoleucine-2041-asparagine, aspartate-2078-glycine, and cysteine-2088-arginine, and glycine-2096-alanine) in these populations. In nine populations, multiple ACCase mutations were present in different individuals. Furthermore, two alleles with different mutations were present in a single plant of rigid ryegrass in two populations.


Weed Science ◽  
2017 ◽  
Vol 66 (2) ◽  
pp. 168-179 ◽  
Author(s):  
Elizabeth Karn ◽  
Roland Beffa ◽  
Marie Jasieniuk

Reduced control of Italian ryegrass in California with herbicides has raised concerns about the evolution of populations with resistance to multiple herbicides. The goal of this study was to investigate variation among populations in plant response and resistance to glyphosate and glufosinate in Italian ryegrass from vineyards and orchards in northwest California. Population resistance screening using field-collected seed revealed up to 56.9% of individuals surviving glyphosate treatment at 1,678 g ae ha−1, and 53.5% of individuals surviving glufosinate treatment at 2,242 g ai ha−1in the same population. Frequencies of surviving plants within populations varied among screening times, particularly for glufosinate. Treating vegetatively propagated, genetically identical tillers with each herbicide pointed to separate mechanisms of resistance rather than cross-resistance to glyphosate and glufosinate. Dose–response experiments were conducted for each herbicide at two different screening times using a subset of populations, field-collected seed, and 10 herbicide rates. Plant survival and biomass were evaluated for each population at 3 wk after treatment and for plant regrowth 1 wk thereafter. Log-logistic regression models fit to the data were used to estimate LD50, GR50, and RD50values and calculate resistance indices (R/S ratios). Based on LD50values, the most highly resistant population was 14.4- to 19.2-fold more resistant to glyphosate than the most susceptible population tested but only 1.6- to 2.0-fold more resistant to glufosinate than the most susceptible population tested. Levels of resistance to both herbicides varied with screening time period and variable measured. Results indicate high frequencies of glyphosate-resistant plants but an early stage in the evolution of glufosinate resistance in some Italian ryegrass populations of northwest California.


Weed Science ◽  
2017 ◽  
Vol 65 (4) ◽  
pp. 452-460 ◽  
Author(s):  
Haitao Gao ◽  
Jiaxing Yu ◽  
Lang Pan ◽  
Xibao Wu ◽  
Liyao Dong

Keng stiffgrass is a serious farmland grass weed distributed globally in winter wheat fields and rice–wheat double-cropping areas. The intensive use of acetyl-CoA carboxylase (ACCase)-inhibiting herbicides has led to the evolution of resistance in a growing number of grass weeds. In this study, whole-plant pot bioassay experiments were conducted to establish that a Keng stiffgrass population from eastern China, JYJD-2, has evolved high-level resistance to fenoxaprop-P-ethyl and moderate resistance to quizalofop-P-ethyl and pinoxaden. Using the derived cleaved amplified polymorphic sequence method, a tryptophan-to-cysteine mutation at codon position 1999 (W1999C) was detected in the ACCase gene of the resistant population JYJD-2. Of the 100 JYJD-2 plants tested, we found 47 heterozygous resistant and 53 homozygous sensitive individuals. In vitro ACCase assays revealed that the IC50value of the ACCase activity of the resistant population JYJD-2 was 6.48-fold higher than that of the susceptible population JYJD-1. To the best of our knowledge, this is the first report of the occurrence of W1999C mutation in the ACCase gene of fenoxaprop-P-ethyl–resistant Keng stiffgrass. This study confirmed the resistance of Keng stiffgrass to the ACCase inhibitor fenoxaprop-P-ethyl, cross-resistance to other ACCase inhibitors, and the resistance being conferred by specific ACCase point mutations at amino acid position 1999.


2018 ◽  
Vol 115 (23) ◽  
pp. 5938-5943 ◽  
Author(s):  
Penelope A. Hancock ◽  
Antoinette Wiebe ◽  
Katherine A. Gleave ◽  
Samir Bhatt ◽  
Ewan Cameron ◽  
...  

The development of insecticide resistance in African malaria vectors threatens the continued efficacy of important vector control methods that rely on a limited set of insecticides. To understand the operational significance of resistance we require quantitative information about levels of resistance in field populations to the suite of vector control insecticides. Estimation of resistance is complicated by the sparsity of observations in field populations, variation in resistance over time and space at local and regional scales, and cross-resistance between different insecticide types. Using observations of the prevalence of resistance in mosquito species from the Anopheles gambiae complex sampled from 1,183 locations throughout Africa, we applied Bayesian geostatistical models to quantify patterns of covariation in resistance phenotypes across different insecticides. For resistance to the three pyrethroids tested, deltamethrin, permethrin, and λ-cyhalothrin, we found consistent forms of covariation across sub-Saharan Africa and covariation between resistance to these pyrethroids and resistance to DDT. We found no evidence of resistance interactions between carbamate and organophosphate insecticides or between these insecticides and those from other classes. For pyrethroids and DDT we found significant associations between predicted mean resistance and the observed frequency of kdr mutations in the Vgsc gene in field mosquito samples, with DDT showing the strongest association. These results improve our capacity to understand and predict resistance patterns throughout Africa and can guide the development of monitoring strategies.


Weed Science ◽  
2018 ◽  
Vol 67 (2) ◽  
pp. 183-188 ◽  
Author(s):  
Wei Deng ◽  
Yingjie Di ◽  
Jingxuan Cai ◽  
Yueyang Chen ◽  
Shuzhong Yuan

AbstractCatchweed bedstraw (Galium aparine L.) is a problematic dicot weed that occurs in major winter wheat (Triticum aestivum L.) fields in China. Tribenuron-methyl has been widely used to control broadleaf weeds since 1988 in China. However, overuse has led to the resistance evolution of G. aparine to tribenuron-methyl. In this study, 20 G. aparine populations collected from Shandong and Henan provinces were used to determine tribenuron-methyl resistance and target-site resistance mechanisms. In dose–response experiments, 12 G. aparine populations showed different resistance levels (2.92 to 842.41-fold) to tribenuron-methyl compared with the susceptible population. Five different acetolactate synthase (ALS) mutations (Pro-197-Leu, Pro-197-Ser, Pro-197-His, Asp-376-Glu, and Trp-574-Leu) were detected in different resistant populations. Individuals heterozygous for Pro-197-Ser and Trp-574-Leu mutations were also observed in a resistant population (HN6). In addition, pHB4 (Pro-197-Ser), pHB7 (Pro-197-His), pHB8 (Pro-197-Leu), pHB5 (Asp-376-Glu), and pHB3 (Trp-574-Leu) subpopulations individually homozygous for specific ALS mutations were generated to evaluate the cross-resistance to ALS-inhibiting herbicides. The pHB4, pHB7, pHB8, pHB5, and pHB3 subpopulations all were resistant to sulfonylurea, pyrazosulfuron-ethyl, triazolopyrimidine, flumetsulam, sulfonylamino-carbonyl-triazolinone, flucarbazone-sodium, pyrimidinyl thiobenzoate, pyribenzoxim, and the imidazolinone imazethapyr. These results indicated the diversity of the resistance-conferring ALS mutations in G. aparine, and all these mutations resulted in broad cross-resistance to five kinds of ALS-inhibiting herbicides.


Weed Science ◽  
2012 ◽  
Vol 60 (2) ◽  
pp. 167-171 ◽  
Author(s):  
Ibrahim A. Mohamed ◽  
Runzhi Li ◽  
Zhenguo You ◽  
Zhaohu Li

Japanese foxtail is one of the most common and competitive annual grass weeds of wheat in China. Whole-plant dose-response experiments were conducted with fenoxaprop and pinoxaden to confirm and characterize resistant and susceptible Japanese foxtail populations and to elucidate the basis of resistance to these herbicides. The resistant Japanese foxtail population was 49-fold resistant to fenoxaprop and 16-fold (cross) resistant to pinoxaden relative to the susceptible population, which was susceptible to both fenoxaprop and pinoxaden herbicides. Molecular analysis of resistance confirmed that the Ile1781to Leu mutation in the resistant population conferred resistance to both fenoxaprop and pinoxaden. This is the first report of cross resistance of Japanese foxtail to pinoxaden in the world and of a target site mutation that corresponded to resistance to both fenoxaprop and pinoxaden in Japanese foxtail. Prior selection pressure from fenoxaprop could result in evolution of resistance to fenoxaprop and cross resistance to pinoxaden in Japanese foxtail population.


Weed Science ◽  
2019 ◽  
Vol 67 (4) ◽  
pp. 389-396
Author(s):  
Ning Zhao ◽  
Yaling Bi ◽  
Cuixia Wu ◽  
Dandan Wang ◽  
Ludan You ◽  
...  

AbstractJapanese foxtail (Alopecurus japonicus Steud.) is an invasive grass weed that severely threatens the production of wheat (Triticum aestivum L.) and canola (Brassica napus L.) crops in eastern Asia. Mesosulfuron-methyl is a highly efficient acetolactate synthase (ALS)-inhibiting herbicide widely used for control of this species in China. However, in recent years, some A. japonicus populations have evolved resistance to mesosulfuron-methyl by different amino acid substitutions (AASs) within the ALS gene. In the current study, 11 populations of A. japonicus were collected from Anhui Province, China, where the wheat fields were severely infested with this weed. Based on single-dose screening, eight of these populations evolved resistance to mesosulfuron-methyl, and gene sequencing revealed three AASs located in codon 197 or 574 of the ALS gene in the different resistant populations. Subsequently, three typical populations, AH-1, AH-4, and AH-10 with Trp-574-Leu, Pro-197-Thr, and Pro-197-Ser mutations, respectively, in ALS genes were selected to characterize their cross-resistance patterns to ALS inhibitors. Compared with the susceptible population AH-S, AH-1 showed broad-spectrum cross-resistance to sulfonylureas (SUs), imidazolinones (IMIs), triazolopyrimidines (TPs), and sulfonyl-aminocarbonyl-triazolinones (SCTs); whereas AH-4 and AH-10 were resistant to SUs, TPs, and SCTs but sensitive to IMIs. Moreover, all three resistant populations were sensitive to both photosystem II inhibitor isoproturon and 4-hydroxyphenylpyruvate dioxygenase inhibitor QYM201 (1-(2-chloro-3-(3-cyclopropyl-5-hydroxy-1-methyl-1H-pyrazole-4-carbonyl)-6-(trifluoromethyl)phenyl)piperidin-2-one). Based on the current state of knowledge, this study is the first report of A. japonicus evolving cross-resistance to ALS-inhibiting herbicides due to a Pro-197-Ser mutation in the ALS gene.


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