Effects Of Chemosterilants Research Articles

Evaluation of chemosterility effect of different insect growth regulators on Bactrocera zonata population.

The indiscriminate application of synthetic pesticides on horticultural plants for the management of Bactrocera zonata has both economic and environmental implications due to the biomagnification of harmful residues in humans via the food chain. This necessitates the use of some eco-friendly control measures such as insect growth regulators (IGRs) as an alternative. A laboratory experiment was laid out to determine the potential chemosterilant effect of five IGRs including pyriproxyfen, novaluron, lufenuron, buprofezin, and flubendiamide at six different concentrations on B. zonata after treating adult diet. Using the oral bioassay, B. zonata were fed on IGRs impregnated diet (50-300 ppm/5 mL diet) which was replaced with the normal diet after 24 h of feeding. Ten pairs of B. zonata were placed in a separate plastic cage accommodating an ovipositor attractant guava for eggs collection and calculation. An analysis of the result revealed that fecundity and hatchability were higher at a low dose and vice versa. Lufenuron at 300 ppm/5 mL of diet significantly decreased the fecundity rate (31.1%) as compared to pyriproxyfen, novaluron, buprofezin and flubendiamide, which had 39.3%, 39.3%, 43.8%, and 47.5%, respectively. The lowest hatchability (19.9%) was noted in lufenuron treated diet followed by pyriproxyfen, novaluron, buprofezin, and flubendiamide, which had 22.1%, 25.0%, 30.9%, and 31.6%, respectively. Furthermore, in a population of crosses between the lufenuron treated male and female, a significant decrease in fecundity (45.5%) and hatchability (51.7%) was noted as compared to other IGRs. Overall, this study identified the chemosterilant potential of lufenuron on the population of B. zonata which can be integrated for its management strategy.

Control of Greenhouse Whitefly (Trialeurodes vaporariorum) Using Visually Attractive Targets Impregnated with Pyriproxyfen

The chemosterilant effect of a photo-stable juvenoid, pyriproxyfen, was investigated on greenhouse whitefly. Yellow fabric lures coated with 1 mg of pyriproxyfen per cm2 drastically suppressed whitefly populations on bean plants in laboratory and glasshouse experiments. Numbers of eggs and larvae were reduced practically to zero over a period of several weeks. The success of such treated rectangular targets (25 cm×5 cm) placed among bean plants in a glasshouse prompted the development of Lano®-Tape, a roll of yellow tape treated with pyriproxyfen. It provides a labor saving method of whitefly control in commercial glasshouses as a substitute for conventional insecticide application techniques. © Pesticide Science Society of Japan

Effects of substituted benzylphenols and triflumuron on the reproduction of the face fly (Diptera: Muscidae).

The chemosterilant effect of various chemicals administered orally, topically, and tarsally on the face fly, Musca autumnalis De Geer, is described. The chemicals tested were J2922, 5-ethoxy-6-[1-(4-methoxyphenyl)ethyl]-1,3-benzodioxole; J2581, 5-ethoxy-6-[1-(4-methoxyphenyl)methyl]-1,3-benzodioxole; J2644, 2,4-bis(1,1-dimethylethyl)-6-(4-methoxyphenylmethyl) phenol, and the benzoylphenylurea triflumuron. J2644 and triflumuron were not toxic at the lowest concentration that caused 100% inhibition of egg hatching and caused sterility even when flies were already inseminated or near oviposition. Minimum sterilizing concentrations of J2922 and J2581 were highly toxic. All chemicals caused 100% sterility in females; only J2644 caused some male sterility. Sterility induced by J2644, J2922, and J2581 in females was reversible and fertility was restored by the third gonotrophic cycle, whereas fertility of females treated with triflumuron was not restored until the fourth cycle. J2922 and J2581 affected egg hatching and ovarian development, as indicated by atrophied ovaries and ovaries containing eggs without respiratory masts. This effect was greater in the second gonotrophic cycle after treatment.

EFFECTS OF THE CHEMOSTERILANT THIOTEPA ON THE SEXUPARAE AND SEXUALES OF THE PEA APHID, ACYRTHOSIPHON PISUM (HOMOPTERA: APHIDIDAE)

Several chemosterilants have been tested against insects (Borkovec 1966). As a result, a total or partial sterility and decrease in fecundity have been noticed in several insects. Amongst Aphididae, Brevicoryne brassicae L., Myzus persicae Sulzer, Aphis fabae Scop., Macrosiphum euphorbiae Thomas, and Acyrthosiphon pisum (Harris) have been tested to determine the effects of chemosterilants like tepa, thiotepa, and metepa (Bonnemaison 1966; Bhalla and Robinson 1966, 1968; Chawla et al. 1973, 1974; Sharma et al. 1980; Steffan and Stüben 1976). In all previous work, either viviparae or their nymphal instars were the object of chemosterilant treatment and up to 95% reduction in fecundity was observed. Nothing to date has been described on the effect of chemosterilants on the sexuparae or sexuales of Aphididae. To continue with the results obtained by Sharma and Thériault (1980) and Sharma et al. (1980) on the viviparae, this paper describes the effects of 0.5% thiotepa [Tris (1-aziridinyl) phosphine sulphide] on sexuparae of the pea aphid, Acyrthosiphon pisum (Harris), and their progeny.

Anopheles stephensi: Effect of Gamma-Radiation and Chemosterilants on the Fertility and Fitness of Males for Sterile Male Releases13

Irradiation of Anopheles stephensi Liston male pupae with 8 krad induced 97.2% male sterility. Higher irradiation of 12 krad resulted in ca. 2% increase of sterility (99.1%) with reduced fitness of males for mating and survival. Four krad irradiation of females resulted in inhibited egg production and at 7 krad there was complete failure of females to lay eggs. Thiotepa was not effective in the sterilization of mosquitoes at the pupal stage. Dipping mosquito pupae in 1% P, P-bis (1-aziridinyl)-N-methylphosphinothioic amide for 2 h induced 100% sterility in both sexes. Chemosterilized males were permanently sterile and comparable in quality (mating competitiveness, mating ability, and survival) with untreated males.

Effect of certain chemosterilants on the larvae of the greasy cutworm, Agrotis ipsilon, Rott

AbstractMetepa und Du‐Ter were applied topically and orally on the fourth instar larvae of the greasy cutworm, Agrotis ipsilon Rott, in the laboratory. Treatments significantly decreased the percentages of pupation and emergence of the larvae, the longevity and fecundity of the produced adults. The pre‐oviposition period of the produced moths was significantly increased by treatments. Topical and oral applications of boths materials to the larvae, sterilized significantly the produced moths. The highest percentage of sterility was obtained when both sexes were produced from treated larvae. Oral application of Metepa and Du‐Ter was more effective in sterilizing the produced moths than topical application of the larvae.ZusammenfassungWirkungen verschiedener Chemosterilantien auf die Raupen von Agrotis ipsilon Rott.Die Viertlarven von A. ipsilon wurden im Labor topikal und oral mit den Chemosterilan‐tien Metepa und DuTer behandelt. Nach Applikation sanken der Prozentsatz der Verpup‐pung und des Falterschlüpfens sowie die Lebensdauer und Fruchtbarkeit der Falter signifi‐kant. Die Präovipositionsperiode der Falter wurde nach Behandlung der Raupen deutlich erhöht. Beide Chemosterilantien führten bei beiden Applikationen zur Sterilisation der Falter. Das höchste Sterilisationsprozent wurde erzielt, wenn beide Geschlechter aus behan‐delten Larven gezogen wurden. Der Sterilisationseffekt von Metepa und DuTer war bei oraler Applikation höher als bei topikaler.

Actions of antifertility chemicals on Xenopus laevis spermatozoa in vitro.

Summary. A test system involving fertilization in vitro of Xenopus laevis gametes was developed to study the effects of various chemosterilants on toad spermatozoa. The subsequent development of fertilized eggs indicated that effective concentrations and times of exposure were considerably greater than those likely to be achieved with antifertility doses to rodents. Low concentrations of tretamine and ethyleneurea on Xenopus spermatozoa produced high yields of abnormal embryos, whereas other epididymal sterilants active in the rat (trimethylphosphate and α-chlorhydrin) were ineffective in very high concentration. Differences between results in vitro and in vivo may be due to environmental variations or indicate an action by certain compounds on epididymal function in rodents rather than a direct action upon spermatozoa.

Potato Aphid: Effects of Five Chemosterilants12

Five chemosterilants were tested against Macrosiphum euphorbiae (Thomas). Tepa, hempa, and N, N′-hexamethylenebis (1-aziridine carboxamide), when applied topically, reduced fecundity of treated adults. Similar depression in fecundity was recorded in progenies obtained from these treated parents. 3,5-bis (dimethylamino)-1,2,4-dithiazolium hydrogen sulfate and 2,4-diamino-6-(1-pyrrolidinyl)-s-triazine hydrochloride were assayed by residual films. The former was somewhat toxic. Though at 0.1 percent, concentration it reduced fecundity of some exposed parents. 2,4-diamino-6-(1-pyrrolidinyl)- s -triazine hydrochloride did not have any chemosterilant effect.

Cytogenetic basis of chemically-induced sterility in Culex pipiens Fatigans Wiedemann. II. Cytopathological effects of certain chemosterilants on the gonadal and embryonic tissues.

Effects of chemosterilants, such as apholate, metepa, tepa and hempa, on the reproductive tissues of Culex pipens fatigans Wied, were studied. In males, the chemosterilant treatments reduced the size of testes at gross level, and caused deficiency of immature sex cells and mature sperm though sperm production continued at a slower rate. Males sterilized by apholate or tepa depleted their sperm earlier than normal males when allowed to mate successively with a fresh batch of virgin females. The sterilant treatments did not affect sperm motility. In adult females, treated ovaries were smaller with fewer number of normally developing follicles and many small, deformed or degenerating follicles. With chemosterilant treatments the number of normally developing follicles decreased in successive gonotrophic cycles. Infertility induced by various chemosterilants in females was found to be permanent. The frequency of non-viable eggs bearing full-grown embryos was more in treated females crossed with normal males than in normal females crossed with treated males. Embryos showed various chromosomal aberrations in early cleavages which inhibited the rate of cell division. Most of these embryos died even before the blastoderm stage. The bearing of the present findings on the mechanism of chemosterilant-induced sterility is discussed.

Insect chemosterilants: a review

In this paper the present status of insect chemosterilants is reviewed. Chemosterilants may be categorised into eight main chemical groups. Practical control measures involving the use of chemosterilants are discussed, also the persistence of these substances when applied to the insect. The gross effects of chemosterilants on insect reproductive systems and also the effects on egg develpment when female insects are mated to chemosterilised males are described, including dominant lethality, reciprocal translocation, enzyme inhibition and sperm inactivation. The possibilities of recovery of fertility and insect resistance to the sterilising effects of chemosterilants are discussed. Endocrine misfunction and chemosterilant action are related. The only practical chemosterilants as control agents are the aziridines although mutagenic hazards associated with these substances preclude their widespread usage. The sterilising activity of certain insect hormone analogues and related substances encourages the belief that safe insect specific sterilising agents can be found.

Toxicity and sterilization effectiveness of aflatoxins B 1 and G 1 and distribution of aflatoxin B 1 - 14 C in house flies.

Aflatoxins B1 and G1were administered orally to adult Musca Domestica L., and their effects on sterility and morality were determined. He ring-labeled aflatoxin B1 also was fed to study the distribution of the ingested compound in the tissues. Aflatoxin C1 was more toxic and more effective as a sterilant than aflatoxin B1. In contrast, aflatoxin B1 has been reported to be more toxic to ducklings and some other animals. Aflatoxin G1 was more toxic to male than to female flies, whereas B1 was equally toxic 10 males and females. Both aflatoxin compounds were temporary sterilants. The amount of 14C present in the haemolymph, fat bodies, ovaries, testes, and heads was measured for 3 days after oral administration of aflatoxin B1-14C. At the end of 3 days, the amount of 14C had decreased in the head, haemolymph and fat bodies, In the ovaries, however, the amount of 14C had increased markedly, while it remained relativity constant in the testes during the 3 days. The accumulation of aflatoxin B1-14C or its metabolites in the Ovaries may account for the temporary chemosterilant effect.

Effects of filipin and cholesterol on housefly, Musca domestica L., and wax moth, Galleria mellonella L.

The effects of filipin on insects are dependent on the molar ratio of cholesterol to filipin. The larvicidal effects of the polyene antibiotic, filipin, can be prevented by excess cholesterol (“excess” herein is defined as a molar ratio of cholesterol to filipin of greater than 2 : 1) in housefly, Musca domestica L., and wax moth, Galleria mellonella L., larvae. Excess cholesterol also prevents the chemosterilant effect of filipin in housefly adults. The filipin-induced inhibition of [ 14C]cholesterol uptake by wax moth larvae is prevented by excess cholesterol; cholesterol uptake is increased severalfold. Dietary filipin, in the absence of added cholesterol, caused loss of 32P from housefly tissues and decreased the incorporation of 32P- and [ 14C]methyl-labeled choline into phospholipids of wax moth tissues. Addition of excess cholesterol to filipin-containing diets enhanced incorporation of 32P into the different classes of phospholipids, and phospholipid synthesis was nearly doubled.

Rapid Dissection of Insects to Determine Ovarial Development1

The beginning of oviposition (Ritcher 1939), the time of ovarial development at different geographical locations (Weaver and King 1954), the rate of egg development during the preoviposition period (Cram 1958), and the determination of whether females are in reproductive diapause (Beards and Strong 1966) have all been determined by dissection of insect ovaries. Moreover, it is often possible to determine whether the female of some insects has mated by removing the bursa to search for the spermatophore (Johnson and Hays 1969). Also, the ovaries reflect the effects of chemosterilants (Wilson and Hays 1969), gonadotropic hormones (Sahota 1969), and irradiation (Strong et al. 1970).

Effect of Vapor and Residual Chemosterilants on Reproduction of Adult Drosophila melanogaster1

Drosophila melanogaster Meigen were sterilized completely when exposed to vapors of 10.0 mg of tepa or metepa for 5 hr. but neither apholate nor tretamine at the same concentration induced complete sterility in either sex, when either sex was exposed to residues for 1 hour, the sterilizing dose of metepa or tepa was 0.20 mg/cm2, but neither sex was completely sterilized by exposure to apholate or tretamine residues at 0.20 mg/cm2 Also, the degree of sterility was related to the time of exposure to Chemosterilant vapors and to the time and concentration of residues. Chemosterilant effects of tepa and metepa residues were retained up to 30 days. The effect of apholate and tretamine decreased with the age of the residue.

Cytogenetic effects of chemosterilants in mosquitoes. III. Development of transplanted ovaries in normal and chemosterilized females ofAedes aegypti

1. Two-day old larvae ofAedes aegypti were reared until pupation in 25 ppm of a commonly used mosquito chemosterilant, apholate. This concentration induced complete female infecundity. 2. Transplantation experiments involving ovaries from normal adults and adults arising from the above chemical treatment were undertaken. The object was to investigate whether apholate-induced female infecundity results from direct effects on the ovary or from indirect effects on the hormonal and/or yolk protein synthesis or supply. 3. The fact that the ovary from an untreated female when implanted in the abdomen of an infecund female develops more or less normally, at least in a qualitative sense, following a blood meal indicates that the yolk proteins and the gonadotrophic hormone are available for ovarian development in chemically treated females. Thus, the humoral factors are not involved in female infecundity and the primary site of action of apholate must be the oocyte. The inhibition of the ovaries in apholate-treated females, must be brought about by degenerative changes in the ovary itself. 4. Quantitatively, fewer untreated follicles developed following implantation in the abdomen of a treated female. Furthermore, they did not reach the same stage of development as they did in untreated environment. Possible mechanisms for this retarded development are discussed.

Suppression of Pest Lepidoptera by Releasing Partially Sterile Males: A Theoretical Appraisal

Scientists at many institutions are investigating the effects of atomic radiation and chemosterilants on reproduction in Lepidoptera. These insects include some of the most destructive pests of agriculture. The ultimate purpose is to utilize sterilized insects to control populations as is now being done with the screw-worm fly, Cochliomyia hominivorax, and certain tephridid fruit flies. Early attempts to sterilize Lepidoptera and other orders of insects emphasized methods that would assure 100% sterility in the insects intended for release.

Comparative effects of chemosterilants on spermatogenic stages in the house fly. II. Recovery of fertility and sperm transfer in successive matings after sterilization with 1,3-propanediol dimethanesulfonate or x-rays.

When 2- to 3-day-old male Musca domestica L. (Diptera: Muscidae) were injected with 20 µg of 1,3 propanediol dimethanesulfonate, most sperm had dominant lethal mutations so the males were sterile in the initial matings. Testes sectioned at regular intervals postinjection contained damaged meiotic and premeiotic cells; pycnotic nuclei were observed 1 day postinjection; and spermatocytes with chromosomal bridges and fragments were observed the 2nd and 3rd day postinjection. Also, the testes contained few spermatocytes the 4th and 5th day postinjection, thus spermatids were scarce the 5th and 7th day. However, sperm production was never completely interrupted, and the level of spermatogenesis 11-13 days postinjection was returning to normal levels. Incontrast, when males were treated with 3 kR of x-rays, all sperm contained dominant lethal mutations, all gonialcells were killed, and the spermatogenic cycle ceased. Males that mated repeatedly after treatment with the chemosterilant recovered their fertility and became as fertile as the controls after 7-8 matings, but the males that did not remate repeatedly did not recover fertility. There was little difference between fertility of males mated 1, 7, or 12 days posttreatment if they remained celibate in the interim. Irradiated males were able to transfer sperm for many matings over several weeks.

Chemosterilization of the two-spotted spider mite. I. Effect of chemosterilants on the biology of the mite.

The effect of the chemosterilants apholate, tepa, 5-fluorouracil, and 5-fluoroorotic acid on Tetranychus urticae Koch was studied. Sterility was induced in T. urticae by all 4 chemosterilants, although the extent of sterility was dependent on the concentration and mode of application of the chemosterilant and the sex, stage of development, and age of the mites. Apholate and tepa sterilized both males and females; 5-fluorouracil and 5-fluoroorotic acid and 5-fluoroorotic acid sterilized the females. Apholate and tepa, as opposed to and tepa, showed complete residual effect. The deutonymph stage was the only immature stage susceptible to chemosterilants. Consistent differences in mortality were observed among the 4-chemosterilants. Tepa induced the highest mortality. Apholate and tepa decreased the longevity of both sexes. All the chemosterilants shortened the life cycle, but the differences among them were not always significant. Apholate and 5-fluorouracil reduced feeding activity significantly in the adult, although this reduction varied with sex. All 4 chemosterilants affected fecundity, the extent of which to varied with the chemosterilant. A positive correlation between fecundity and feeding habit was found. The results of test to determine effects on mating competitiveness were not consistent.

Comparative effects of chemosterilants on spermatogenic stages in the house fly I. Induction of dominant lethal mutations in mature sperm and gonial cell death

Adult house flies, Musca domestica L., were treated with 12 chemosterilants: 6 aziridines (apholate, tepa, tretamine, 2 bifunctional carboxamines—ENT-50838 and ENT-50172—and the bifunctional compound ENT-51909); 3 ethanesulfonates (2 bifunctional compounds and the monofunctional compound, EMS); hempa, nitrogen mustard, and diepoxybutane. Dominant lethal mutations in the mature sperm were measured and gonial cell killing was studied cytologically. At the minimum doses that induced dominant lethal mutations in all the sperm, some compounds, usually the aziridines and hempa, killed all the gonial cells and no sign of any spermatogenic activity was found in testes 14 days post-treatment. With the sulfonates, there was no destruction of gonial cells and a completely normal level of spermatogenic activity was found even though dominant lethals were induced in the sperm. In fact, with methanediol dimethanesulfonate (ENT-51799), doses that were 4 times higher than the sterilizing dose for mature sperm failed to kill gonial cells. Configuration of the carrier molecule also played an important role in determining the effects on gonial cells. Since recovery of fertility is associated with survival of gonial cells and continued spermatogenic activity, all 12 compounds could be classified as those that would: (1) permit no recovery, (2) permit complete recovery, or (3) those in which recovery of fertility was most likely.

The Permanent and Cumulative Effect of Tepa-Induced Sterility in Male Japanese Beetles1

The permanence of the chemosterilant effect of tepa on male Popillia japonica Newman was investigated in 2 experiments. In the first, tepa-treated male beetles were confined with virgin female beetles, eggs were collected at various intervals, and sterility was determined for successive periods. In the second, successive groups of females were paired with a group of treated males and the fertility of eggs deposited by the females determined. In neither study was there evidence of a decline in sterility or indication that the tepa-induced sterility of the male was not permanent. When male beetles were topically treated with consecutive daily increments of tepa, the fertility of eggs obtained from paired females indicated that the effects of the additive doses were cumulative.