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Concentration-mortality relationship in field populations of B. tabaci exposed to bifenthrin, methamidophos and endosulfan
Source publication
Field populations of Hypothenemus hampei (Ferrari), Plutella xylostella (L.), Spodoptera exigua (Hübner), Helicoverpa zea (Boddie) and Bemisia tabaci (Gennadius) were tested for resistance to several insecticides commonly used in Nicariagua. Assays were conducted to estimate the LD50s or LC50s and the corresponding resistance ratios. A diagnostic c...
Contexts in source publication
Context 1
... tabaci. For bifenthrin the LC 50 s of B. tabaci collected at El Viejo, Sé baco, and Nandaime were 4 Ð 45 times higher than the LC 50 of the susceptible population (Table 5). Of the latter three Þeld popu- lations, the LC 50 of bifenthrin in the population from Nandaime was signiÞcantly higher than the LC 50 of the populations from El Viejo and Sé baco, suggesting that the use of bifenthrin is more intensive in Nan- daime than the other two localities. ...
Context 2
... the latter three Þeld popu- lations, the LC 50 of bifenthrin in the population from Nandaime was signiÞcantly higher than the LC 50 of the populations from El Viejo and Sé baco, suggesting that the use of bifenthrin is more intensive in Nan- daime than the other two localities. In the case of methamidophos, the LC 50 s of the four Þeld popula- tions were 56 Ð546 times higher than the correspond- ing LC 50 of the susceptible population ( Table 5). The populations from Sé baco and Nandaime were col- lected from tomato Þelds and showed signiÞcantly higher LC 50 s to methamidophos than the populations from El Viejo and Leó n, both collected from cucurbit crops, where insecticides are not as intensively used compared with tomato crops. ...
Context 3
... populations from Sé baco and Nandaime were col- lected from tomato Þelds and showed signiÞcantly higher LC 50 s to methamidophos than the populations from El Viejo and Leó n, both collected from cucurbit crops, where insecticides are not as intensively used compared with tomato crops. The B. tabaci popula- tions from El Viejo, Sé baco and Nandaime had 31 to 59 times higher LC 50 values than the susceptible population (Table 5), indicating the presence of en- dosulfan-resistant populations of B. tabaci in Nicara- gua. The responses to endosulfan in the populations from El Viejo, Sé baco, and Nandaime were similar, because the 95% FL of the corresponding LC 50 s over- lap. ...
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... Such resistance has been also documented in insects like triatomine bugs [37]. In agriculture plagues, resistance to common insecticides has increased during the last eight decades [38,39]. Although some oral medications for human use can affect fecundity and mortality of hematophagous insects, such as Cimex lectularius L, the required dosage in most studies reaches the maximum permitted concentration in plasma [40]. ...
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... In Honduras and Costa Rica, spray regimes of nine applications per crop cycle were reported in 1997, and by 1999, this was increased to 16 applications per crop cycle [6,14]. More than two decades later, farmers report the same or higher number of applications [6,13,15]. ...
The diamondback moth, Plutella xylostella (L.), is a worldwide pest of brassica crops, resistant to a large number of insecticides. As an alternative, the use of pheromone-baited traps has been proposed but farmers are yet to be convinced. In the present study, we aimed to validate the benefits of the use of pheromone-baited traps for monitoring and mass trapping in cabbage production in Central America as means of Integrated Pest Management (IPM) in comparison to calendarized insecticide sprays, which are the farmers’ current practices (FCP). Mass trapping was established in nine selected plots of cabbage in Costa Rica and Nicaragua. Average captures of males/trap/night, plant damage and net profits of these IPM plots were compared to simultaneously evaluated or historically reported FCP plots. The results indicate that in Costa Rica, trap captures did not justify the application of insecticides and average net profits increased by more than 11% when the trapping methods were implemented. In Nicaragua, IPM plots were able to reduce insecticide applications to one third of those in FCP plots. These results confirm the economic and environmental benefits of pheromone-based management of DBM in Central America.
... During the 1990s, pyrethroid insecticides became the primary class for managing H. zea. However, in isolated populations of H. zea, signs of resistance to pyrethriod appeared and continued throughout the 1990s-2000s (Abd-Elghafar et al 1993, Kanga et al 1996, Pérez et al. 2000, Pietrantonio et al. 2007, Flood and Rabaey 2007, Hopkins and Pietrantonio 2008, Jacobson et al. 2009). ...
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... Monitoring of insecticide resistance for B. tabaci is extensively being conducted in many countries from the Africa (Dittrich et al. 1990a;Kady and Devine 2003;Farghaly 2010), America (Prabhaker et al. 1985(Prabhaker et al. , 1989(Prabhaker et al. , 2005Dittrich et al. 1990a;Pérez et al. 2000;Silva et al. 2009;Cardona et al. 2001;Cahill et al. 1995;Dennehy et al. 2010;Schuster et al. 2010;Castle et al. 2014;Li et al. 2012), Asia (Kranthi et al. 2001;Byrne et al. 1994;Ahmad et al. 2002Ahmad et al. , 2010Basit et al. 2013;Horowitz et al. , 2005Kontsedalov et al. 2012;Erdogan et al. 2008;Naveen et al. 2017;Shadmany et al. 2015;Luo et al. 2010;Wang et al. 2017b) and Europe (Nauen et al. 2002;Elbert and Nauen 2000;Fernández et al. 2009;Roditakis et al. 2005Roditakis et al. , 2009) . ...
... Q-type in USA is >1000-fold resistance to IGRs . In Nicariagua, B.tabaci is 20-40-fold resístanse to bifenthrin, methamidophos and endosulfan (Pérez et al. 2000). Btype in Columbia and Ecuador is 10-50-fold, 10-40and > 50-fold resistance to methomyl, cypermethrin and methamidophos, respectively (Cardona et al. 1998(Cardona et al. , 2001. ...
The whitefly, Bemisia tabaci Gennadius (Hemiptera: Aleyrodidae) is a worldwide pest of major crops. It is a highly adaptable insect pest and resists almost all chemical compounds used for its control. It resists at a 7–30 fold, 7–4931-, 20–80-, and 12–2461 fold to various compounds of cyclodiene, organophosphates, carbamates and pyrethroid, respectively. It also resists up to 2000 fold to neonicotinoids and buprofezin. However, B. tabaci resists to some level to pyradabin, spiromesifen, pymetrozine, fipronil, diafenthuron and spinosaid. Resistance in B. tabaci is quite unstable in the absence of selection pressure, and cross-resistance within and between chemical groups is an established phenomenon. Further, inheritance of insecticide resistance in B. tabaci exclusively appears autosomal and partially recessive but resistance to pyriproxyfen and bifenthrin in Q-and B-type varies from incomplete to complete dominance. Furthermore, resistance to imidacloprid, bifenthrin, fenvelerate and pyriproxyfen is controlled by more than one gene (factor). However, resistance to pyriproxyfen in Q-type appears to be under the control of one factor. Mechanism of insecticide resistance and cost of fitness in this insect has also been discussed.
... To reduce yield losses caused by DBM, farmers routinely use chemical control, mainly because of the lack of reliable alternatives and the availability of relatively cheap insecticides (Talekar and Shelton, 1993). Nevertheless, this type of control has proved to be ineffective as, in some cases, even 20 insecticide applications per crop cycle have not reduced the losses it causes (Pérez et al., 2000). In some cases, it is usual for farmers to adopt three (Castelo and Gatehouse, 2001) or even four insecticide applications a week (de Oliveira et al., 2011). ...
The diamondback moth, Plutella xylostella (L.) (Plutellidae: Yponomeutoidea) is the most destructive pest in Brassicaceae crops worldwide. This paper describes the status of P. xylostella and its natural enemies in a wide area around Córdoba city in the central region of Argentina. Samples were collected from fifteen horticultural plots near Córdoba City. In each plot, larvae and pupae were obtained from 10 cabbage plants during the spring of 2016 and 2017. Immature specimens were kept until an adult DBM or a parasitoid emerged. Maximum density of immature individuals per plant occurred at different moments in each sampling site, indicating local effects and dynamics of the pest. Higher densities of immature P. xylostella were observed in sites in the north-east horticultural zone of Córdoba city, where most of the farms are located. The percentage of total parasitism also varied between sites and between years but, in general, higher percentages of parasitism were observed at the end of the sampling season. Five parasitoid species were identified: Siphona sp. (Diptera: Tachinidae), Diadegma leontiniae (Hymenoptera: Ichneumonidae), Apanteles piceotrichosus (Hymenoptera: Braconidae), Oomyzus sokolowskii (Hymenoptera: Eulophidae) and the hyperparasitoid Conura pseudofulvovariegata (Hymenoptera: Chalcididae). Parasitoids behaved in a similar way to P. xylostella. Densities and dynamics were particular to each sampling site. Implications for management are discussed.
