scholarly journals Durable resistance against Meloidogyne chitwoodi and M. fallax

2017 ◽  
Vol 38 (SI 2 - 6th Conf EFPP 2002) ◽  
pp. 711-713
Author(s):  
F.C. Zoon ◽  
W. Golinowski ◽  
R. Janssen ◽  
D. Mugniéry ◽  
M.S. Phillips ◽  
...  

The EU-funded Project QLRT-1999-1462 DREAM (Durable Resistance Against Meloidogyne) aims to contribute to sustainable production systems by developing a strategy for durable resistance management for two polyphagous quarantine root-knot nematodes Meloidogyne chitwoodi and M. fallax. The objective will be achieved by integrating expertise in breeding, nematology, botany and molecular biology. The project combines three areas of research: 1. Identification and incorporation of resistance in important arable crops: potato, pepper, ryegrass and fodder radish, 2. Study of variation in nematode virulence and of durability of the resistance, and 3. Optimising of production systems by rotation schemes. The main results expected are: resistant germplasm, characterised pathogen collections, breeding methods, knowledge of the stability of resistance, molecular markers linked to resistance and (a)virulence, resistance mechanisms and genes, genetic maps, and improved rotation schemes. The strategy and some first results will be discussed.

2020 ◽  
Vol 24 (1) ◽  
pp. 61
Author(s):  
Danarsi Diptaningsari ◽  
Y. Andi Trisyono ◽  
Aziz Purwantoro ◽  
Arman Wijonarko

Imidacloprid is one of the insecticides that has been widely used to control the brown planthopper (Nilaparvata lugens Stål.). The excessive use of insecticides led to the development of insecticide resistance in N. lugens. This study was aimed to determine the stability of resistance to imidacloprid in N. lugens from Banyumas, Central Java Province. The five generations of selection increased the resistance ratio (RR) from 46.20-fold to 150.39-fold. To assess the stability of resistance to imidacloprid in N. lugens, the fifth generation was further reared for 10 generations without exposure to insecticides. The stability studies showed that resistance to imidacloprid was unstable with a decrease of resistance from 150.39-fold to 38.14-fold after 10 generations without selections. Continuous selections with imidacloprid for three generations could increase the resistance level from 150.39-fold to 216.13-fold. The unstable resistance could be managed by removing the selection pressure for a period of time or switching to insecticides with different mode of actions. Information regarding resistance stability would be useful to determine an effective resistance management strategies in N. lugens.


2008 ◽  
Vol 98 (4) ◽  
pp. 355-359 ◽  
Author(s):  
P. Bielza ◽  
V. Quinto ◽  
C. Grávalos ◽  
E. Fernández ◽  
J. Abellán ◽  
...  

AbstractThe stability of spinosad resistance in western flower thrips (WFT),Frankliniella occidentalis(Pergande), populations with differing initial frequencies of resistance was studied in laboratory conditions. The stability of resistance was assessed in bimonthly residual bioassays in five populations with initial frequencies of 100, 75, 50, 25 and 0% of resistant individuals. There were no consistent changes in susceptibility of the susceptible strain after eight months without insecticide pressure. In the resistant strain, very highly resistant to spinosad (RF50>23,000-fold), resistance was maintained up to eight months without further exposure to spinosad. In the absence of any immigration of susceptible genes into the population, resistance was stable. In the case of the population with different initial frequency of resistant thrips, spinosad resistance declined significantly two months later in the absence of selection pressure. With successive generations, these strains did not change significantly in sensitivity. Spinosad resistance inF. occidentalisdeclined significantly in the absence of selection pressure and the presence of susceptible WFT. These results suggest that spinosad resistance probably is unstable under field conditions, primarily due to the immigration of susceptible WFT. Factors influencing stability or reversion of spinosad resistance are discussed.


2016 ◽  
Vol 7 (2) ◽  
pp. 208-214
Author(s):  
P. Chemineau

The future livestock systems at the world level will have to produce more in the perspective of the population increase in the next 30 years, whereas reducing their environmental footprint and addressing societal concerns. In that perspective, we may wonder if animal health and animal welfare, which are two essential components of production systems, may play an important role in the stability of the three pillars of sustainability of the livestock systems. We already know that objectives driven by economy, environment and society may modify animal welfare and animal health, but is the reverse true? The answer is yes and in 11 cases out of 12 of the matrix health-welfare×3 pillars of sustainability×positive or negative change, we have many examples indicating that animal health and animal welfare are able to modify, positively or negatively, the three pillars of sustainability. Moreover, we also have good examples of strong interactions between health and welfare. These elements play in favour of an holistic approach at the farm level and of a multicriterial definition of what could be the sustainable systems of animal production in the future which will respect animal welfare and maintain a good animal health.


2006 ◽  
Vol 63 (6) ◽  
pp. 572-578 ◽  
Author(s):  
Valéria Rodrigues Lavigne de Mello Paim ◽  
Edna Dora Martins Newman Luz ◽  
José Luís Pires ◽  
Stela Dalva Vieira Midlej Silva ◽  
Jorge Teodoro de Souza ◽  
...  

The witches' broom disease caused by the fungus Crinipellis perniciosa is the main phytossanitary constraint for cacao production in Brazil. The integrated management of the disease involves resistance as one of the components. The breeding program conducted by the Brazilian Institution, CEPLAC is directed toward the pyramidation of resistance genes from different sources to achieve a more durable resistance. This study aimed to identify sources of resistance in progenies of cacao accessions collected in the basins of ten Amazonian rivers and compared to progenies from the Peruvian clones 'Scavina 6' and 'Sacavina 12'. Progenies from 40 Amazonian accessions and 'Scavina' were evaluated in the field for six years for witches' broom resistance through multivariate and repeated measurement analyses evaluating the effect of progeny, area, block, year, and their interactions. There were differences in the mean number of vegetative brooms on some Amazonian progenies and 'Scavina' descendants. There was an increase in the number of vegetative brooms in the last year for 'Scavina' progenies, but that was not observed for the Amazonian progenies 64, 66, 156, 194, 195, 269 and 274. There were different gene/alleles for resistance in the Amazonian progenies in comparison to the traditional 'Scavina' accessions. These new sources of resistance will be important for pyramiding resistance genes and consequently increasing the stability and durability of the resistance to witches' broom.


2020 ◽  
pp. 26-39
Author(s):  
V.L. Baburin

The article examines the influence of natural history and socio-cultural processes on the formation of industrial areas within the borders of modern Russia and partially the Russian Empire and the USSR. Basically, the evolutionary approach is used in the version of cyclic genetic dynamics. To assess the long-term effects of the “path dependence”, we analyze the 150-year cycle of industrialization within the borders of Historical Russia. To do this, we use the mechanisms of spatial localization of Kondratiev cycles and associated technological structures of the first (first-second), second (third-fourth)) and the third (fifth) industrial revolution. As an information base, data on the number of people employed and the volume of industrial production (in comparable prices) are used, and for the XX century, data on the dynamics of fixed assets of industry are also used. The relationship between modernization schemes on the old basis (within the boundaries of old industrial areas) and in the areas of pioneer development is revealed. The stability of industry specializations within the grid of industrial areas is considered separately. Based on the results obtained, the conclusion is made about the stability of old industrial cores of localization of industrial potential, the continuity of the spectrum of their specializations (not the replacement of old industries with new ones, but the addition). There is also a repetition in the regions of the new development of the General scheme of the chosen path and the inherited track.


Author(s):  
Ivelin Pantchev ◽  
Goritsa Rakleova ◽  
Atanas Atanassov

Abstract The research community is deeply convinced that RNA is unstable in the environment. Its roots rise from numerous failed attempts to isolate functional cellular RNA molecules. Further support had originated from the fast turnover of RNA in the cells. The situation changed recently with the discovery that externally applied dsRNA can produce targeted gene silencing in plant-feeding insects. First results have demonstrated that external dsRNA can successfully pass the insect gastrointestinal tract and reach its final destination within the body cells. This was somewhat unexpected and sparked new interest in RNA stability in the environment and its fate in the insect organism. In this brief review we make an attempt to summarize current knowledge and to propose a model of how dsRNA can perform its function under these settings.


2015 ◽  
Vol 105 (6) ◽  
pp. 712-716
Author(s):  
E. AlSuhaibani ◽  
C.C. Voudouris ◽  
R. Al-Atiyat ◽  
A. Kotzamumin ◽  
J. Vontas ◽  
...  

AbstractAphids are important agricultural pests worldwide. Their control is largely based on chemical insecticides. One species that shows important invasive abilities and host-plant-related differences is Therioaphis trifolii (Monell) (Hemiptera: Aphididae). T. trifolii maculata, also known as spotted alfalfa aphid (SAA), can be very injurious to alfalfa crops in certain regions, such as in Saudi Arabia for effective control it is essential to diagnose and monitor the resistance mechanisms in the SAA populations. In the present study, we analysed acetylcholinesterase (ace) target site insensitivity mechanisms. A 650 bp length DNA containing the putative acetylcholinesterase (ace1) precursor was obtained and compared with other Hemipteran species. The sequences of many individual aphids collected from alfalfa crops in Saudi Arabia were analysed for the presence of resistance mutations: no resistance mutations were found at the resistance mutation loci 302; however, the presence of a serine–phenylalanine substitution (S431F) was identified in one individual. The S431F substitution, has been shown to confer significant levels of both organophosphate and carbamate resistance in other aphid species, and is now found for the first time in T. trifolii. We subsequently developed a simple polymerase chain reaction–restriction fragment length polymorphism assays for the S431F mutation, using a TaqI restriction site destroyed by the S431F mutation. The novel diagnostic assay may support the implementation of Insecticide Resistance Management strategies, for the control of SAA in alfalfa crops in the Kingdom of Saudi Arabia, and other countries worldwide.


2007 ◽  
Vol 97 (2) ◽  
pp. 191-200 ◽  
Author(s):  
A. Khaliq ◽  
M.N.R. Attique ◽  
A.H. Sayyed

AbstractThe susceptibility of representative pyrethroid (cypermethrin, deltamethrin, lambdacyhalothrin, bifenthrin), organophosphate (chlorpyriphos, triazophos, profenophos) and new chemistry insecticides (spinosad, indoxacarb and emamectin) was investigated for 18 field populations ofPlutella xylostella(Linnaeus) from three different zones in Pakistan. The LC50(mg ml−1; 48 h) values of pyrethroids for various populations ranged from 0.19–1.88 for cypermethrin, 0.31–2.64 for deltamethrin, 0.08–1.16 for lambdacyhalothrin and 0.07–0.88 for bifenthrin. The LC50(mg ml−1; 48 h) of organophosphates ranged from 0.52–5.67 for chlorpyriphos, 0.37–4.14 for triazophos and 0.03–2.65 for profenophos. The most probable reason for low toxicity of organophosphates and pyrethroids is the evolution of multiple resistance mechanisms; however, further studies are required to establish these mechanisms. When these same products were tested against a susceptible laboratory population (Lab-Pak), the new chemistry compounds were significantly more toxic than pyrethroids and organophosphates. The results are discussed in relation to integrated pest management and insecticide resistance management strategies forP. xylostella.


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