Cattle ticks, Boophilus microplus, resistant to DDT, BHC, and Dieldrin

Cattle ticks on a property in central Queensland, where there had been a previous history of DDT-resistance, were not readily controlled by dipping infested cattle in 0.05 per cent. w/v gamma-BHC or 0.05 per cent. w/v dieldrin after these chemicals had been in use for 10 and 4 months respectively. Spraying of steers artificially infested with ticks taken from this property 9 months later, indicated resistance to DDT and dieldrin, but not to "Diazinon". Immersion tests with larvae and engorged adult females of this strain showed them to be respectively about 9 and 20 times as resistant to DDT as those of a susceptible reference strain. The engorged females were shown to be more than 700 times as resistant to dieldrin. When tested by an injection method, the engorged adult females of this strain showed a resistance to DDT and dieldrin of 5 and 12 times respectively, some resistance to BHC, but no resistance to Bayer 21/199. Similarly tested engorged adult females of another strain taken from the property 15 months later showed a resistance to DDT of 8 times.

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Toxaphene-resistant cattle ticks (Boophilus microplus (Canestrini)) occurring in Queensland

Australian Journal of Agricultural Research ◽

10.1071/ar9560211 ◽

1956 ◽

Vol 7 (3) ◽

pp. 211 ◽

Cited By ~ 10

Author(s):

KR Norris ◽

BF Stone

Keyword(s):

Body Weight ◽

Reference Strain ◽

Boophilus Microplus ◽

Peanut Oil ◽

Lethal Concentration ◽

Median Lethal Concentration ◽

Subcutaneous Injections ◽

Cattle Ticks ◽

History Of ◽

Very High

Cattle ticks on four herds in southern Queensland survived dipping in a vat charged with 0.5 per cent. w/v toxaphene, which nevertheless disinfested a fifth herd. Protective periods afforded by toxaphene against attachment of resistant larvae were much shorter than against susceptible strains. Laboratory concentration-response tests on a culture of the toxaphene-resistant ticks indicated that the median lethal concentration of toxaphene for engorged females was 19 times higher than that of a reference strain, and t h at f o r the larvae was also significantly higher. The toxaphene-resistant ticks were not affected when cows were sprayed with 0.05 per cent. w/v gamma-BHC. This was consistent with an earlier history of BHC resistance in the ticks on these herds. Spraying trials indicated no marked arsenic resistance in the toxaphene-resistant ticks. The mortality of the toxaphene-resistant ticks on cattle sprayed with 0.5 per cent. W/V pp'-DDT, and the protective period against larval reinfestation, were as high as usually observed in other tick populations. A very high kill resulted from spraying the toxaphene-resistant ticks with 0.05 per cent. w/v diazinon. Subcutaneous injections of peanut oil solutions of lindane, dieldrin, and aldrin at the rate of 25 mg toxicant/kg host body weight were without effect on toxaphene-resistant ticks.

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The inheritance of DDT-resistance in the cattle tick, Boophilus microplus

Australian Journal of Agricultural Research ◽

10.1071/ar9620984 ◽

1962 ◽

Vol 13 (5) ◽

pp. 984 ◽

Cited By ~ 15

Author(s):

BF Stone

Keyword(s):

Resistant Strain ◽

Reference Strain ◽

Boophilus Microplus ◽

Autosomal Gene ◽

Cattle Tick ◽

Adult Females ◽

Ddt Resistance ◽

High Level ◽

Multiresistant Strain

Adults of a DDT-resistant strain of the cattle tick from central Queensland were crossed with adults of a susceptible reference strain, by means of cardboard mating boxes glued to the skins of cattle. F1, backcross, and F2 larvae were tested for resistance to DDT by enclosure of larvae in filter paper packets impregnated with oil solutions of pp'-DDT. F1 and backcross engorged adult females were tested for resistance by injection with oil solutions of pp'-DDT. There was no evidence of departure from a 1 : 1 ratio in the backcrosses or from a 1 : 2 : 1 ratio in the F2, and there was little difference between the compositions of the F1 reciprocal crosses or among the backcrosses derived from them. Therefore DDT resistance in this strain was considered to be due to a single, incompletely recessive, autosomal gene. Engorged nymphs of the resistant strain moulted later in vitro than nymphs of the susceptible strain, and resistant engorged adult females detached from the host later than susceptible engorged adult females. After 13 generations of DDT-free culturing of a multiresistant strain, the percentage of homozygous DDT-resistant ticks in the strain had fallen from a high level to about 55%. This figure remained constant for a further 10 generations.

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Selection of cattle for tick resistance, and the effect of herds of different susceptibility on Boophilus populations

Australian Journal of Agricultural Research ◽

10.1071/ar9620974 ◽

1962 ◽

Vol 13 (5) ◽

pp. 974 ◽

Cited By ~ 32

Author(s):

PR Wilkinson

Keyword(s):

Tick Infestation ◽

Tick Control ◽

Boophilus Microplus ◽

Skin Thickness ◽

Adult Females ◽

Cattle Ticks ◽

In Parenthesis ◽

Tick Counts ◽

Tick Resistance ◽

Selection Of

Weekly counts of Boophilus microplus (Canestrini) on 30 Australian Illawarra Shorthorn heifers enabled the cattle to be ranked in order of tick infestation, with highly significant correlations between counts of two observers and between counts of one observer on different occasions. In May 1960, when the heifers were 1½–2 years old, 12 were selected as relatively tick-resistant and 12 as relatively tick-susceptible. Each of these groups was divided at random into herds of six, and the four herds were then allotted randomly to separate paddocks, each onequarter of the area previously grazed. A herd was sprayed with 0.5% DDT emulsion when its average count of ticks (adult females over 5 mm in length) on one side of the animals exceeded 40. During the ensuing tick season, from October 5, 1960, to June 7, 1961, the sums of average weekly tick counts, and the numbers of sprayings (in parenthesis) were: susceptible herds 4853 (5) and 5962 (6): resistant herds 718 (0) and 1073 (1). Counts of tick larvae on defined body areas showed that, in the summer after segregation, resistant herds carried fewer larvae than the susceptible herds, apparently because fewer mature ticks fell from the resistant cattle in the preceding spring and winter. As a consequence of this, counts of adult ticks were comparatively lower after than before segregation. There was little or no 'spring rise' of tick infestation on the resistant herds. There was no significant correlation between tick resistance and coat score, sweat gland dimensions, or total skin thickness, but a correlation of -0.53 with follicle depth was significant at the 1% level. There was no evidence of adaptation of cattle ticks to the resistant animals, either in the field experiment or in observations on stalled cattle. The experiment draws attention to the appreciable proportion of tick-resistant animals within the Australian Illawarra Shorthorn breed, which has largely been overlooked in past discussions on tick-resistant breeds of cattle. It also suggests a technique for estimating the improvement in tick control that may be obtained by a given degree of selection within any breed, for any given environment.

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A method for measuring the acaricide-susceptibility of the cattle tick Boophilus microplus (Can.)

Bulletin of Entomological Research ◽

10.1017/s000748530004832x ◽

1962 ◽

Vol 53 (3) ◽

pp. 563-578 ◽

Cited By ~ 205

Author(s):

B. F. Stone ◽

K. P. Haydock

Keyword(s):

Statistical Evidence ◽

Boophilus Microplus ◽

Cattle Tick ◽

Simple Method ◽

Adult Females ◽

Ddt Resistance ◽

Filter Papers

A simple method is described of testing the susceptibility to acaricides of larvae of the cattle tick Boophilus microplus (Can.) in Queensland, Australia, by enclosing them in packets made from rectangular filter papers, folded once and secured along the remaining three sides by spring clips, that had been impregnated with Risella-oil solutions of DDT, dieldrin, or Bayer 21/199 (coumaphos), or with deposits from xylene solutions of Dilan. The response of susceptible engorged adult females to dieldrin was tested similarly. Five out of six experiments showed statistical evidence of repeatability of results in determination of relative DDT-resistance of larvae. There was a slight increase in susceptibility of non-resistant larvae to DDT with increasing age between 7 and 28 days for fresh packets but not for re-used packets. In three out of four tests, re-used packets were significantly more toxic (up to 1·40 times) to susceptible larvae than fresh packets. In one test a loss of toxicity occurred after storage of Bayer 21/199 packets for 23 days. The possible use of this method for measuring resistance in ticks is discussed.

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The inheritance of dieldrin-resistance in the cattle tick, Boophilus microplus

Australian Journal of Agricultural Research ◽

10.1071/ar9621008 ◽

1962 ◽

Vol 13 (5) ◽

pp. 1008 ◽

Cited By ~ 12

Author(s):

BF Stone

Keyword(s):

Filter Paper ◽

Reference Strain ◽

Boophilus Microplus ◽

Autosomal Gene ◽

Cattle Tick ◽

Laboratory Population ◽

Reciprocal Crosses ◽

Adult Females ◽

Multiresistant Strain

Adults of a dieldrin-resistant straiu of cattle tick from southern Queensland were crossed with adults of a susceptible reference strain, by means of cardboard mating boxes glued to the skins of cattle. The F1 and backcross larvae were tested for resistance by enclosure in filter paper packets impregnated with oil solutions of dieldrin. The corresponding engorged adult females were tested by injection with oil solutions of dieldrin. There was no evidence of significant departure from a 1 : 1 ratio of resistant and susceptible phenotypes in the backcrosses, and there was little difference between the composition of the F1 reciprocal crosses or between the backcrosses derived from them. Dieldrin-resistance in this strain appears to be due to a single, dominant autosomal gene. Dieldrin-resistant ticks in a multiresistant strain from central Queensland steadily declined from 50–60% to an undetectable percentage in a laboratory population bred in the absence of dieldrin for 24 generations.

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Dieldrin-resistant cattle ticks, Boophilus microplus (Canestrini) in Queensland

Australian Journal of Agricultural Research ◽

10.1071/ar9570312 ◽

1957 ◽

Vol 8 (3) ◽

pp. 312 ◽

Cited By ~ 8

Author(s):

BF Stone ◽

RAJ Meyers

Keyword(s):

Adult Female ◽

Strong Evidence ◽

Laboratory Tests ◽

Reference Strain ◽

Boophilus Microplus ◽

Lethal Concentration ◽

Median Lethal Concentration ◽

Cattle Ticks

Infestation by cattle ticks in a herd a t Mt. Gravatt, near Brisbane, in southern Queensland, could not be controlled by repeated spraying of the cattle with 0.05 per cent. w/v dieldrin. Ninety-eight per cent. of engorged females of this strain, which fell from an artificially infested beast in the 48 hr following spraying with 0.05 per cent. w/v dieldrin, laid normal batches of viable eggs. Spraying cattle with 0.05 per cent. w/v "Diazinon", however, readily controlled infestation by this strain. Laboratory concentration-response tests on a culture of the dieldrin-resistant ticks indicated that the median lethal concentration of dieldrin for the larvae was over 2000 times higher than for those of a reference strain. There was also strong evidence from laboratory tests of dieldrin resistance in the engorged adult female ticks.

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Brain Cholinesterase Activity and Its Inheritance in Cattle Tick (Boophilus Microplus) Strains Resistant and Susceptible to Organophosphorus Acaricides

Australian Journal of Biological Sciences ◽

10.1071/bi9680321 ◽

1968 ◽

Vol 21 (2) ◽

pp. 321 ◽

Cited By ~ 15

Author(s):

BF Stone

Keyword(s):

Ache Activity ◽

Reference Strain ◽

Cholinesterase Activity ◽

Organophosphorus Compounds ◽

Boophilus Microplus ◽

Cattle Tick ◽

Biochemical Method ◽

Cattle Ticks ◽

Homozygous Resistant ◽

Brain Acetylcholinesterase

Brain acetylcholinesterase (AChE) activities of individual cattle ticks, B. microplus, of an organophosphorus-resistant strain were compared with those of a standard reference strain. When measured by a histochemical-densitometric method on photographic transparencies and by a biochemical method, brains from homozygous resistant adult female ticks had about 12% of the AChE activity of brains from homozygous susceptible ticks_ Brains of hybrid adult females had about 78%, histochemically and biochemically, of the AChE activity of their susceptible parents, indicating that low AChE activity was incompletely recessive although the associated resistance to organophosphorus compounds had been shown previously to be incompletely dominant_

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Biochemical Genetics of Resistance to Organophosphorus Acaricides in Three Strains of the Cattle Tick, Boophilus microplus

Australian Journal of Biological Sciences ◽

10.1071/bi9760265 ◽

1976 ◽

Vol 29 (3) ◽

pp. 265 ◽

Cited By ~ 11

Author(s):

Bernard F Stone ◽

James Nolan ◽

Charles A Schuntner

Keyword(s):

Ache Activity ◽

Reference Strain ◽

Organophosphorus Compounds ◽

Boophilus Microplus ◽

Cattle Tick ◽

Biochemical Genetics ◽

Genetics Of Resistance ◽

Adult Females ◽

Degree Of Dominance ◽

Brain Ache Activity

Three aspects of the biochemical genetics of resistance to organophosphorus compounds in the Biarra (B), Mackay (M) and Ridgelands (R) strains of the cattle tick B. microp/us were studied. These were: decreased acetylcholinesterase (AChE) activity in adult brains of strains Band M; decreased AChE sensitivity to inhibitors in adult brains and in larvae of strains B, M and R; and increased detoxication in larvae and adult females of strain M. Comparisons were made with a susceptible reference strain (S). Microspectrophotometric estimations of AChE activity in histochemical preparations of whole brains showed that hybrids had levels of activity approximately intermediate between those of the parental strains. Homogenates of brains from hybrids assayed biochemically gave similar but more precise results which indicated that decreased brain AChE activity was neither recessive nor dominant (degree of dominance, D = + O� 02) in strain B and incompletely recessive (D = - O� 26) in strain M. The proportions of brains showing decreased AChE activity in testcross and F 2 progenies indicated that decreased AChE activity in strains Band M is controlled by single autosomal genes.

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