scholarly journals Levels, inheritance and stability of resistance to Bacillus thuringiensis formulation in a field population of the diamondback moth, Plutella xylostella (Lepidoptera: Plutellidae) from Thailand

1999 ◽  
Vol 34 (1) ◽  
pp. 23-29 ◽  
Author(s):  
Katsuki Imai ◽  
Yuhzoh Mori
Keyword(s):  
Bacillus Thuringiensis ◽  
Plutella Xylostella ◽  
Diamondback Moth ◽  
Field Population ◽  
Stability Of Resistance

scholarly journals Cross-Resistance and Stability of Resistance to Bacillus thuringiensis Toxin Cry1C in Diamondback Moth

2001 ◽  
Vol 67 (7) ◽  
pp. 3216-3219 ◽  
Author(s):  
Yong-Biao Liu ◽  
Bruce E. Tabashnik ◽  
Susan K. Meyer ◽  
Neil Crickmore
Keyword(s):  
Bacillus Thuringiensis ◽  
Plutella Xylostella ◽  
Resistant Strain ◽  
Diamondback Moth ◽  
Field Population ◽  
Cross Resistance ◽  
Bacillus Thuringiensis Toxin ◽  
Stability Of Resistance ◽  
Resistant Strains ◽  
Reported Data

ABSTRACT We tested toxins of Bacillus thuringiensis against larvae from susceptible, Cry1C-resistant, and Cry1A-resistant strains of diamondback moth (Plutella xylostella). The Cry1C-resistant strain, which was derived from a field population that had evolved resistance to B. thuringiensis subsp.kurstaki and B. thuringiensis subsp.aizawai, was selected repeatedly with Cry1C in the laboratory. The Cry1C-resistant strain had strong cross-resistance to Cry1Ab, Cry1Ac, and Cry1F, low to moderate cross-resistance to Cry1Aa and Cry9Ca, and no cross-resistance to Cry1Bb, Cry1Ja, and Cry2A. Resistance to Cry1C declined when selection was relaxed. Together with previously reported data, the new data on the cross-resistance of a Cry1C-resistant strain reported here suggest that resistance to Cry1A and Cry1C toxins confers little or no cross-resistance to Cry1Bb, Cry2Aa, or Cry9Ca. Therefore, these toxins might be useful in rotations or combinations with Cry1A and Cry1C toxins. Cry9Ca was much more potent than Cry1Bb or Cry2Aa and thus might be especially useful against diamondback moth.

scholarly journals Genetic and Biochemical Characterization of Field-Evolved Resistance to Bacillus thuringiensis Toxin Cry1Ac in the Diamondback Moth, Plutella xylostella

2004 ◽  
Vol 70 (12) ◽  
pp. 7010-7017 ◽  
Author(s):  
Ali H. Sayyed ◽  
Ben Raymond ◽  
M. Sales Ibiza-Palacios ◽  
Baltasar Escriche ◽  
Denis J. Wright
Keyword(s):  
Bacillus Thuringiensis ◽  
Resistance Genes ◽  
Plutella Xylostella ◽  
Biochemical Characterization ◽  
Diamondback Moth ◽  
Field Population ◽  
Laboratory Population ◽  
Binding Studies ◽  
Slow Increase ◽  
Evolution Of Resistance

ABSTRACT The long-term usefulness of Bacillus thuringiensis Cry toxins, either in sprays or in transgenic crops, may be compromised by the evolution of resistance in target insects. Managing the evolution of resistance to B. thuringiensis toxins requires extensive knowledge about the mechanisms, genetics, and ecology of resistance genes. To date, laboratory-selected populations have provided information on the diverse genetics and mechanisms of resistance to B. thuringiensis, highly resistant field populations being rare. However, the selection pressures on field and laboratory populations are very different and may produce resistance genes with distinct characteristics. In order to better understand the genetics, biochemical mechanisms, and ecology of field-evolved resistance, a diamondback moth (Plutella xylostella) field population (Karak) which had been exposed to intensive spraying with B. thuringiensis subsp. kurstaki was collected from Malaysia. We detected a very high level of resistance to Cry1Ac; high levels of resistance to B. thuringiensis subsp. kurstaki Cry1Aa, Cry1Ab, and Cry1Fa; and a moderate level of resistance to Cry1Ca. The toxicity of Cry1Ja to the Karak population was not significantly different from that to a standard laboratory population (LAB-UK). Notable features of the Karak population were that field-selected resistance to B. thuringiensis subsp. kurstaki did not decline at all in unselected populations over 11 generations in laboratory microcosm experiments and that resistance to Cry1Ac declined only threefold over the same period. This finding may be due to a lack of fitness costs expressed by resistance strains, since such costs can be environmentally dependent and may not occur under ordinary laboratory culture conditions. Alternatively, resistance in the Karak population may have been near fixation, leading to a very slow increase in heterozygosity. Reciprocal genetic crosses between Karak and LAB-UK populations indicated that resistance was autosomal and recessive. At the highest dose of Cry1Ac tested, resistance was completely recessive, while at the lowest dose, it was incompletely dominant. A direct test of monogenic inheritance based on a backcross of F1 progeny with the Karak population suggested that resistance to Cry1Ac was controlled by a single locus. Binding studies with 125I-labeled Cry1Ab and Cry1Ac revealed greatly reduced binding to brush border membrane vesicles prepared from this field population.

Inheritance of resistance to aBacillus thuringiensistoxin in a field population of diamondback moth (Plutella xylostella)

1995 ◽  
Vol 43 (2) ◽  
pp. 115-120 ◽  
Author(s):  
Amparo C. Martínez-Ramírez ◽  
Baltasar Escriche ◽  
M. Dolores Real ◽  
Francisco J. Silva ◽  
Juan Ferré
Keyword(s):  
Plutella Xylostella ◽  
Diamondback Moth ◽  
Field Population ◽  
Inheritance Of Resistance

Enhancement of δ-Endotoxin Activity by Toxin-Free Spore of Bacillus thuringiensis against the Diamondback Moth, Plutella xylostella

1994 ◽  
Vol 63 (1) ◽  
pp. 111-112 ◽  
Author(s):  
Minoru Miyasono ◽  
Shyuichiro Inagaki ◽  
Makiko Yamamoto ◽  
Katsuaki Ohba ◽  
Takeo Ishiguro ◽  
...  
Keyword(s):  
Bacillus Thuringiensis ◽  
Plutella Xylostella ◽  
Diamondback Moth ◽  
Endotoxin Activity ◽  
Free Spore

scholarly journals Insecticidal Effects of Organotin(IV) Compounds on Plutella Xylostella (L.) Larvae. II. Inhibitory Potencies Against Acetylcholinesterase and Evidence for Synergism in Tests With Bacillus Thuringiensis(BER.) and Malathion

1994 ◽  
Vol 1 (1) ◽  
pp. 1-17 ◽  
Author(s):  
Nazni W. Ahmad ◽  
Tay Siew Huang ◽  
S. Balabaskaran ◽  
K. M. Lo ◽  
V. G. Kumar Das
Keyword(s):  
Bacillus Thuringiensis ◽  
Plutella Xylostella ◽  
Resistant Strain ◽  
Synergistic Effects ◽  
Diamondback Moth ◽  
Ache Inhibition ◽  
Microbial Insecticide ◽  
In Vitro Inhibition ◽  
Sublethal Concentrations

Features of pesticide synergism and acetylcholinesterase (AChE) inhibition (in vitro) were studied using a selected range of organotin compounds against the early 4th instar larvae of a highly resistant strain of the diamondback moth (DBM), Plutella xylostella, a major universal pest of cruciferous vegetables.Fourteen triorganotin compounds were evaluated for their ability to enhance the toxicity of the microbial insecticide, Bacillus thuringiensis (BT) and of the commercial insecticide, Malathion to Plutella xylostella larvae. Supplemental synergism was observed with triphenyl- and tricyclopentyltin hydroxides in combinations with Bacillus thuringiensis. Increased synergism was observed with an increase in the number of cyclopentyl groups on tin in the mixed series, CypnPh3-n SnX, where X = OH, and 1-(1,2,4-triazolyl). The combination of (p-chlorophenyl)diphenyltin N,N-dimethyldithiocarbamate at LD10 and LD25 concentrations with sublethal concentrations of Malathion as well as of tricyclohexyltin methanesulphonate at the 0.01% (w/v) concentration with Malathion exerted strong synergistic effects (supplemental synergism) with toxicity index (T.I) values of 7.2, 19.8 and 10.1, respectively.Studies on the in vitro inhibition of acetylcholinesterase prepared from the DBM larvae showed that while most of the triorganotin Compounds tested were without effect on the enzyme, compounds containing the thiocarbamylacetate or the dithiocarbamylacetate moieties demonstrated appreciable levels of inhibition, being comparable in efficacy to commercial grades of Malathion and Methomyl.

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