Malathion Resistance Research Articles

Malathion Resistance in Indianmeal Moths (Lepidoptera: Pyralidae) Infesting Stored Corn and Wheat in the North-Central United States1

Forty-three strains of Pladia interpunctella (Hubner) were collected from grain bins on farms in nine midwestern states. Thirty-nine of the 43 strains were more than 17-fold resistant to malathion. None of 10 resistant strains tested were cross-resistant to chlorpyrifos methyl. Of six resistant strains assayed for malathion carboxylesterase activity, all had greatly elevated levels over those of a susceptible strain. The a-monoacid of malathion was the major hydrolysis product in all six resistant strains. When esterase electrophoretograms were prepared of 16 strains, ranging from purely susceptible to purely resistant, a good correlation was observed between resistance level and the staining intensity of certain esterase bands. We conclude that carboxylesterase-type malathion-specific resistance is epidemic in Indianmeal moth populations throughout the U.S. grain belt.

A method for the rapid detection of malathion resistance in Plodia interpunctella (Hübner) (Lepidoptera: Pyralidae) with further records of resistance

A method for the rapid diagnosis of resistance to malathion in adult Plodia interpunctella (Hübner) is described. Moths were exposed to a dry film of malathion coating conical flasks and knockdown was used as the criterion of response. A pooter to minimise damage to moths during handling is described. From probit mortality lines a discriminating dose killing all moths of susceptible strains was derived. Of 15 strains of P. interpunctella tested, resistance to malathion was detected in strains from Kenya, Nigeria and the U.S.A. and in strains imported into the U.K. on foodstuffs originating from Argentina, the Republic of South Africa and the U.S.A.

Malathion resistance in Tribolium strains and their hybrids: inheritance patterns and possible enzymatic mechanisms (Coleoptera, Tenebrionidae).

(1) The genetics of malathion resistance in two strains of the flour beetle, Tribolium castaneum, was investigated. In CTC-12, resistance is polygenic, while in Kano, it is due to a dominant allele at a single autosomal locus. Reciprocal hybrids with the susceptible control strains bb and pp showed an overdominant response in particular when Kano was the male parent in the original cross. (2) Three possible genetic mechanisms to explain these results are discussed. The model which best explains the genetic results, particularly the difference between the reciprocal crosses, assumes a modifier resistance allele on the Y chromosome. (3) The levels of activity of total esterases, carboxylesterases, mixed-function oxidases, epoxide hydrase, and glutathione transferase in the parent strains and their hybrids were measured quantitatively. Although total esterase activity may not be relevant for the breakdown of malathion, it was inhibited by the pesticide. The activity of the microsomal enzymes was high in CTC-12, low in bb, and intermediate in the hybrids, while carboxylesterases were very active in Kano as well as in the hybrids with bb and low in the latter. These patterns agree with the genetics of resistance in the two strains. A higher level of GSH transferase in the Kano x bb hybrids than in Kano seems to indicate a possible biochemical mechanism for their overdominant resistance.

Insecticide Resistance in Selected Stored-Product Insects Infesting Peanuts in the Southeastern United States1

Field strains of the Indian meal moth, Plodia interpunctella (Hübner), the almond moth, Ephestia cautella (Walker), and the red flour beetle, Tribolium castaneum (Herbst), collected from peanut and oilseed storage facilities throughout the Southeastern United States, were tested for susceptibility to malathion, dichlorvos, and pirimiphos-methyl [Actellic]. Probit-mortality regression lines indicate that malathion resistance is both widespread and severe, but no dichlorvos resistance was detected in any strain tested. No significant cross-resistance to pirimiphos-methyl was evident, although flat slopes for the dosage-mortality regression lines for several P. interpunctella strains indicate a potential for the development of resistance to this insecticide.

The biochemical nature of malathion resistance in Anopheles stephensi from Pakistan

Malathion resistance in Anopheles stephensi from Pakistan was synergized by triphenyl phosphate, primarily a carboxylesterase inhibitor. There was a slight degree of antagonism with piperonyl butoxide. The major metabolite of malathion in larvae of both the resistant and susceptible strains was malathion monocarboxylic acid. Resistant larvae produced about twice as much of this product as the susceptible larvae. This suggests that a qualitative or a quantitative change in a carboxylesterase enzyme may be the basis of malathion resistance in this strain. Analysis of general esterase levels to α- and β-naphthyl acetate showed that there was no quantitative change in the amount of carboxylesterase enzyme present in the resistant strain as compared to the susceptible.

The association between malathion resistance and acetylcholinesterase in Drosophila melanogaster.

The relationship between the 50% survival time for flies feeding on a malathion-containing medium and the activity of acetylcholinesterase (AChE) was determined for 15 isofemale lines of Drosophila melanogaster. A significant correlation was found (r = 0.28, P less than 0.05), with more resistant lines tending to have a lower level of AChE activity. An association between AChE and malathion resistance was also observed in a selection experiment. The AChE activity decreased in two of two populations selected for malathion resistance. AChE from these populations was altered in kinetic parameters (measured in crude head extracts) and electrophoretic mobility. Although the "resistant" AChE had a lower activity (Vm) on either a per milligram protein or a per individual basis, its apparent Km for acetylthiocholine was lower than that of "susceptible" AChE. Recombination mapping of both low activity and fast electrophoretic mobility localized these traits to the region of the structural locus (Ace) on the third chromosome. The AChE activity of flies heterozygous for a variety of Ace lesions (kindly provided by Dr. W. M. Gelbart) was consistent with this location. The changes in AChE were suggested to have been caused by selection of alleles at the Ace locus.

Genetic and ecological properties of malathion resistance in a “field” strain of the flour beetle, tribolium castaneum (tenebrionidae, coleoptera)

AbstractA field‐collected strain of Tribolium castaneum, initially somewhat more malathion resistant than the control laboratory strain, became much more resistant in less than 8 generations of selection. Resistance is shown to be due to a dominant allele at a single autosomal locus. No deleterious changes in fitness accompanied the increase in resistance. The laboratory strain did not respond to selection apparently for absence of relevant genetic variation.SummaryA field collected strain of the flour beetle Tribolium castaneum, called Solet, was found to be more malathion resistant as well as more variable genetically than a control strain, CSbb. In no more than 8 generations of selection by topical application, mortality dropped to very low levels despite a 20‐fold increase in dose. LC50 could not be reached even at the highest dose (1 %) which the experimenters could handle without discomfort to themselves.Genetic analyses indicated that malathion resistance in Solet is inherited as a dominant allele at a single, autosomal locus.Selection was ineffective in the control strain, apparently due to the lack of genetic variation at loci controlling resistance.The potential for developing insecticide resistance in Tribolium underlines the need for research on alternative control measures.ZusammenfassungGenetische und ökologische Merkmale der Malathion‐Resistenz eines Wildstammes des Mehlkäfers, Tribolium castaneum (Tenebrionidae, Coleoptera)Ein in einem Lager gesammelter Stamm (“Solet”) von T. castaneum erwies sich als stärker Malathion‐resistent sowie als genetisch variabler als ein Laborstamm (“CSbb”). In nur 8 mit topicaler Applikation selektionierten Generationen sank die Mortalität trotz 20‐facher Dosis‐Steigerung auf ein sehr tiefes Niveau. Die LC50 konnte selbst bei der Höchstdosis von 1 % (mit der eine Handhabung gerade noch ohne eigene Gefährdung möglich war) nicht erreicht werden.Die genetische Analyse zeigte, daß die Malathion‐Resistenz beim Stamm Solet auf einem dominanten Allel an einer singulären, autosomalen Stelle beruht. Die Selektion war beim Kontrollstamm, offensichtlich aufgrund fehlender genetischer Variation, wirkungslos.Die Fähigkeit von Tribolium, hohe Insektizidresistenz zu entwickeln, unterstreicht die Notwendigkeit, nach alternativen Bekämpfungsmöglichkeiten zu suchen.

イエバエにおけるマラチオン抵抗性遺伝子の連鎖群解析

イエバエにおけるマラチオン抵抗性遺伝子の連鎖群解析

Genetic differences in malathion avoidance and resistance in Drosophila melanogaster.

Eight strains of wild-caught melanogaster were tested for their responses to the insecticide malathion. The types of responses tested were behavioral resistance (contact avoidance) and physiological resistance. For both types of responses, significant interstrain differences were detected. Avoidance index values for each strain and sex fell into five significantly different groups. No significant correlation was found between behavioral and physiological responses, indicating that the mechanisms involved are genetically independent of each other.

Combinations of pirimiphos‐methyl and carbaryl for stored grain protection

AbstractIn laboratory experiments, whole wheat was treated with pirimiphos‐methyl or carbaryl or combinations of these two insecticides; the treated grain was then adjusted to a 12% moisture content and stored at 25°C for bioassay at various intervals over a period of 39 weeks. Pirimiphos‐methyl at 5.1 mg kg−1 effectively controlled Sitophilus granarius (L.) and Tribolium confusum Jacquelin du Val but was ineffective against Rhyzopertha dominica (F.) CRD 118, a strain showing malathion resistance. Conversely, carbaryl at 6.5 mg kg−1 (but not at 3.1 mg kg−1) was effective against R. dominica, but ineffective against the other two species. A combination of pirimiphosmethyl + carbaryl, at 1.8 + 5.1 mg kg−1, controlled S. granarius and R dominica but not T. confusum, whilst a 4.2 + 3.4 mg kg−1 combination was relatively more effective against T. confusum but less so against R. dominica. In a separate experiment, whole wheat was treated with carbaryl at 2.5, 5.0 and 7.5 mg kg−1 (nominal rates). Samples were stored and, at various times after the treatments, were bioassayed with R. dominica CRD 2, at 20, 25, 30 and 35°C. The results were comparable with those for the CRD 118 strain, but efficacy was reduced at higher temperatures. The combination of pirimiphos‐methyl at 4–5 mg kg−1 and carbaryl at 5–6 mg kg−1 is suggested as a potentially useful grain protectant where R. dominica is a problem and long term storage is required. These results are discussed in relation to the protection of stored grain in Australia.

The effect of holding adult Oryzaephilus surinamensis (L.) (Coleoptera: Silvanidae) at different temperatures on their subsequent susceptibility to malathion

There is reason to believe that the temperature prior to exposure may effect the response of adult Oryzaephilus surinamensis to the recommended discriminating dose test for malathion resistance. Experiments were carried out in which four malathion resistant strains of O. surinamensis were kept at 15, 20, 25 and 30°C for two weeks prior to testing at 25 C. It was found that conditioning at the lower temperatures resulted in a significantly higher knockdown than conditioning at the higher temperatures. For each 5°C fall in conditioning temperature there was a 7.5% increase in knockdown. Chemical analysis showed that in the first hour of exposure more malathion was taken up by the beetles conditioned at lower temperatures than by those conditioned at the higher temperatures.

Esterases and Malathion Resistance in Brown Planthopper

Esterases and Malathion Resistance in Brown Planthopper

Malathion resistance in Aedes aegypti of Puerto Rico induced by selection pressure on larvae.

A high level of tolerance to malathion occurred in Aedes aegypti larvae of San Juan, Puerto Rico in 1978. The tolerance was 7-fold when compared with a susceptible strain. Malathion selection pressure in the laboratory on this tolerant strain resulted in resistance after only six filial generations. The resistance of the F6 generation as 10-fold when compared with the strain as it was in the field in 1969, and 19-fold when compared with a susceptible laboratory strain. The results, together with those of previous studies suggest that resistance may be a major factor in situations in Puerto Rico in which malathion failed to control Ae. aegypti.

SURVEY OF INSECTICIDE RESISTANCE IN PLODIA INTERPUNCTELLA (HUBNER), EPHESTIA CAUTELLA (WALKER) AND E. KUEHN1ELLA ZELLER (LEPIDOPTERA: PYRALIDAE) IN NEW SOUTH WALES

AbstractA survey is reported of resistance to DDT, dieldrin, fenitrothion and malathion in last instar larvae from cultures of Pladia interpunctella (Hübner), Ephestia cautella (Walker) and E. kuehniella Zeller, established from samples collected in New South Wales, 1974‐1977. Resistance to DDT and dieldrin was detected in most samples. Resistance to malathion was widely distributed in P. interpunctella and E. cautella. Fenitrothion resistance in these species was not as widespread as the former resistance. Malathion resistance was diagnosed in E. kuehniella but further sampling is required to show its distribution. Fenitrothion resistance was not diagnosed in larvae of this species.Pre‐treatment of larvae with triphenyl phosphate was found to be a useful indicator of the type of malathion resistance present.

Untersuchungen über Resistenz gegen Malathion und Lindan bei vorratsschädlichen Käferarten in der Bundesrepublik Deutschland

A survey of the occurrence of malathion and lindane resistance of stored product beetles in the Federal Republic of Germany is given. Malathion resistance was found in one species, lindane resistance in four species. Highest resistance to lindane was found in a strain ofTribolium castaneum (RF=16,7).

INSECTICIDE RESISTANCE IN PLODIA INTERPUNCTELLA (HUBNER) (LEPIDOPTERA: PYRALIDAE) IN NEW SOUTH WALES, AUSTRALIA

AbstractThree strains of Indian meal moth, Plodia interpunctella, were collected in 1975 from stored foodstuffs and grain storages in New South Wales and their responses to 24 insecticides were compared with a laboratory reference strain. The strains showed 68‐, 74.4‐ and 72.3‐fold resistance to endrin, > 53‐fold to dieldrin, 12.5‐, 14.2‐ and 11.5‐fold resistance to lindane, and > 42‐fold resistance to DDT. One strain from Tamworth (strain T) displayed more than 260‐fold resistance to malathion and two strains (R and M) showed 25‐ and 24‐fold resistance to malathion. The three strains also had resistance to dichlorvos (2.9 to 3.6‐fold), diazinon (7.0 to 9.7‐fold), pirimiphos‐methyl (4.5 to 4.8‐fold) and fenitrothion (7.2 to 8.6‐fold). Pre‐treatment with triphenyl phosphate overcame most of the malathion resistance of strain T, reducing the resistance factor by more than 97% to 7.4, compared with only 20% and 17% reductions in strains R and M to 20. None of the strains was resistant to pyrethrins, synthetic pyrethroids or the carbamate, methomyl.

Laboratory and Field Studies on the Use of Temephos against Body Lice in Egypt

Abstract Due to the development of DDT and BHC resistance in body lice, Pcdiculus humanus humanus in Egypt, malathion is the insecticide used for the current control campaigns. Another effective and safe insecticide is needed with which they may be controlled if malathion resistance develops. Temephos dust at 1% a.i. is the chosen material. A single dusting reduced the degree of lousiness by more than 90%. This reduction was maintained for about 23 days. There was no ovicidal effect and no control of the human flea Pulex irritans.

Genetic linkage of malathion resistance in the German cockroach.

<i>Genetic linkage of malathion resistance in the German cockroach.</i>

Malathion Resistance in Some Populations of the Indian Meal Moth Infesting Dried Fruits and Tree Nuts in California13

Three of 5 native populations and a laboratory strain of Plodia interpunctella (Hubner) were found resistant to malathion. A susceptible population stressed with malathion showed a 110-fold increase in resistance in 5 generations. Reciprocal crosses of malathion-resistant and malathion-susceptible Indian meal moths showed that transport of resistant insects into an area where only susceptible moths are found may cause an increase in resistant moths in that area.

Malathion resistance in strains of Tribolium castaneum collected from rice in the U.S.A.

Malathion resistance in strains of Tribolium castaneum collected from rice in the U.S.A.