Effects of the chitin synthesis inhibitor buprofezin on survival and development of immatures of Chrysoperla rufilabris (Neuroptera: Chrysopidae)

Effects of buprofezin (Applaud), a chitin synthesis inhibitor, on survival and development of eggs, three instars, and pupae of Chrysoperla rufilabris (Burmeister) were determined in the laboratory. Buprofezin at three tested concentrations (100, 500, and 1,000 mg [AI]/liter) did not affect the viability and development of eggs when the eggs were treated, or third instars and pupae when those stages were treated. Although the degree of effects by buprofezin on larvae varied with instar, buprofezin at the higher concentrations (500 and 1,000 mg [AI]/liter) reduced survival rates 17-47% and prolonged the overall development from first instars to adult emergence by 2 or 3 d when first instars were treated, indicating that the first instar is the most vulnerable stage. When second instars were treated, the survival of C. rufilabris from second instars to pupae was not significantly affected. However, the developmental time from second instar to adult emergence was longer in the treatments with the highest concentration (1,000 mg [AI]/liter) than that with the lowest concentration (100 mg [AI]/liter). The compatibility of buprofezin with natural enemies in integrated pest management programs is discussed.     

Effects of a juvenile hormone analog, pyriproxyfen, on the apterous form of Lipaphis erysimi

Effects of a juvenile hormone analog, pyriproxyfen, on various developmental stadia of the apterous form of the turnip aphid, Lipaphis erysimi (Kaltenbach), were bioassayed at three concentrations (50, 100, and 150 mg [AI]/l) in the laboratory. Supernumerary-molted nymphs with 1-3 extra molts were found when the first three nymphal instars were treated, and all these nymphs died prematurely. In contrast, all treated fourth instar nymphs molted normally to adults. The longevity of all pyriproxyfen-treated L. erysimi nymphs and adults and the fecundity of treated adults were reduced by 50%. Higher concentrations of pyriproxyfen (100 and 150 mg [AI]/l) caused sterility in adults from treated fourth instars; whereas the lowest concentration (50 mg [AI]/l) did not cause any adult sterility. A majority of adults from treated fourth instars and treated adults produced normal nymphs, and some adults produced dead nymphs with normal appendages or dead and deformed nymphs without any appendages. Normal nymphs produced by the adults from treated adults or treated at fourth instars developed more slowly from first instar to adult than the water-treated nymphs, and all adults in the new generation apparently reproduced normally. The potential role of pyriproxyfen in a vegetable aphid IPM program was discussed.     

Effects of three modern insecticides, pyriproxyfen, spinosad and tebufenozide, on survival and reproduction of Chrysoperla carnea adults

Three novel insecticides, pyriproxyfen, spinosad and tebufenozide, were evaluated for their effect on survival and reproduction of Chrysoperla carnea adults using two methods of exposure: direct contact and ingestion. Pyriproxyfen and tebufenozide proved to be harmless to adult survival, whereas spinosad 72 h after treatment reduced the number of adults by 39.8% and 87.2% in topical and ingestion treatment at the maximum concentration recommended (800 mg a.i. litre^?1). Fecundity was not affected irrespective of the insecticide or time of application (before or after the onset of oviposition). Concerning fertility, only pyriproxyfen exerted a negative effect on hatching when the eggs were deposited by females treated by ingestion in the post‐oviposition period at the highest concentration tested (150 mg a.i. litre^?1).     

Effects of lufenuron on Lobesia botrana (Lepidoptera: Tortricidae) egg, larval, and adult stages

The effect of the chitin synthesis inhibitor lufenuron was evaluated against different developmental stages of Lobesia botrana Den. & Schiff. (Lepidoptera: Tortricidae). Lufenuron fed to adults at 10 ppm reduced their fecundity and fertility, but it did not affect adult longevity. High activity was observed against L. botrana eggs with greater effect on 1-d-old eggs than on the other age classes and on eggs treated by direct contact rather than those laid on a previously treated surface. Eggs laid by treated adults showed the same effects during development as eggs treated by contact or those laid on a treated surface. Larvae that emerged from treated eggs could not perforate grape berries. Administered into the diet, lufenuron had a larvicidal effect, resulting in similar LC50 values for different instars: 0.07 ppm for first instars, 0.08 ppm for third instars, and 0.11 ppm for fifth instars. None of the larvae treated with sublethal concentrations throughout their life emerged as adults at the highest concentration (0.08 ppm), and only 70% emerged at the lowest concentration (0.0025 ppm).     

Laboratory evaluation of lufenuron on immature stages of potato tuber moth (Lepidoptera: Gelechiidae)

The effects of the chitin synthesis inhibitor lufenuron against potato tuber moth, Phthorimaea operculella (Zeller), eggs were determined by topically exposing different age groups of eggs (1-4 d old) to treated potato tubers (Solanum tuberosum L.) under laboratory conditions. Larval hatch from both treated (4 and 12 g [AI]/100 liter) and untreated tubers was >95%, but mortality of first instars was high in treated tubers (>90%) compared with untreated tubers. Examination of the treated tubers showed that most of the larvae were unable to penetrate or cause any noticeable damage to the potato tubers. However, the few first instars that survived were able to penetrate the tubers and continue their development to the pupal or adult stages. At 12 g (AI)/100 liter, adult emergence was <2% and most of the emerged adults had morphological deformities such as reduced wing size and they were unable to free themselves from the pupal sacs. These data suggest that topical application of lufenuron to eggs before larval hatch would reduce the amount of damage caused by potato tuber moth as part of integrated pest management program.     

Offspring performance in dynamic habitats: key factors for a riparian carabid beetle

Abstract.  1. Knowledge of the ecology of carabid species is largely restricted to adults, although larval mortality is assumed to be the key factor in overall mortality. As low-mobility larvae are unable to avoid unfavourable conditions, habitat selection of reproducing adults should be clearly affected by the habitat factors which determine offspring performance.
2. The present study examines the key habitat factors governing the distribution patterns of Bembidion velox larvae and adults on the river banks of the River Elbe by means of habitat suitability models. The validity of the determined habitat factors for offspring performance and survival was tested in laboratory experiments.
3. In the field, B. velox adults as well as larvae show a strong association with semi-terrestrial, sandy, open soil habitats.
4. In the laboratory, overall mortality of larvae reared in different substrates was lowest in sand of medium grain size mixed with fine and coarse sand. The first larval instars in particular reacted sensitively to variations in grain size. Furthermore, flood resistance of eggs was demonstrated, as 90% of larvae hatched under permanently flooded conditions.
5. Short development times were recorded, with 4–7 days for hatching of young larvae from eggs after oviposition and approximately 28 days for the development of adults from newly hatched larvae. This probably increases the survival probability for the pre-imaginal stages in dynamic habitats.
6. In conclusion, it can be said that reproductive success is strongly dependent on oviposition site selection by adults as this reflects the ecological demands of the immature stages.     

The Insect Growth Regulator Pyriproxyfen Terminates Egg Diapause in the Asian Tiger Mosquito,Aedes albopictus

The Asian tiger mosquito, Aedes albopictus, is a highly invasive mosquito species that transmits chikungunya and dengue. This species overwinters as diapausing eggs in temperate climates. Early diapause termination may be a beneficial strategy for winter mosquito control; however, a mechanism to terminate the diapause process using chemicals is not known. We tested the hypothesis that a hormonal imbalance caused by the administration of juvenile hormone analog would terminate egg diapause in A. albopictus. We tested the insect growth regulator pyriproxyfen on all developmental stages to identify a susceptible stage for diapause termination. We found that pyriproxyfen treatment of mosquito eggs terminated embryonic diapause. The highest rates of diapause termination were recorded in newly deposited (78.9%) and fully embryonated (74.7%) eggs at 0.1 and 1 ppm, respectively. Hatching was completed earlier in newly deposited eggs (25–30 days) compared to fully embryonated eggs (71–80 days). The combined mortality from premature diapause termination and ovicidal activity was 98.2% in newly deposited and >98.9% in fully embryonated eggs at 1 ppm. The control diapause eggs did not hatch under diapausing conditions. Pyriproxyfen exposure to larvae, pupae and adults did not prevent the females from ovipositing diapausing eggs. There was no effect of pyriproxyfen on diapausing egg embryonic developmental time. We also observed mortality in diapausing eggs laid by females exposed to pyriproxyfen immediately after blood feeding. There was no mortality in eggs laid by females that survived larval and pupal exposures. In conclusion, diapausing eggs were the more susceptible to pyriproxyfen diapause termination compared to other life stages. This is the first report of diapause termination in A. albopictus with a juvenile hormone analog. We believe our findings will be useful in developing a new control strategy against overwintering mosquito populations.     

The effect of host stage and temperature on selected developmental parameters of the solitary endoparasitoid Meteorus gyrator (Thun.) (Hym., Braconidae)

Abstract:  The development of the solitary endoparasitoid Meteorus gyrator was compared in the six larval stages of its host, the tomato moth Lacanobia oleracea , and at five constant temperatures. The host instar at the time of parasitism had a marked effect on the larval developmental period of the parasitoid, such that larvae derived from eggs oviposited in first instar hosts took approximately 18 days to egress, whilst those derived from eggs oviposited in sixth instar hosts took <10 days. The weight of cocoons was greatest when oviposition was into final instar hosts, where female cocoons averaged 12.8 mg, and lowest in those derived from eggs oviposited into first instars (9.2 mg). The parasitoid's larval development rate in third instar hosts increased with temperature increments in a linear fashion up to 25°C , after which development times were only marginally increased. At 10°C, the mean larval development time was approximately 90 days and pupal development 35–40 days, whilst at 25°C development times were 10–11 days for larvae and 6–7 days for the pupae. In the majority of cases, overall development times were marginally longer (<1 day) in females than in males.     

Potential for intraguild predation and competition among predatory Coccinellidae and Chrysopidae

In a laboratory study two coccinellid species, Coleomegilla maculata (DeGeer) and Harmonia axyridis Pallas, completed preimaginal development on lacewing eggs, Chrysoperla carnea Stephens or pea aphids, Acyrthosiphon pisum (Harris) in similar times. Preimaginal survival on C. carnea eggs was similar to survival on A. pisum for all stages of C. maculata and H. axyridis. Coccinellid adults that developed on C. carnea eggs were smaller than adults reared on A. pisum. Coccinella septempunctata L. did not complete preimaginal development on C. carnea eggs. Chrysoperla carnea preimaginal developmental time was approximately 20 days when fed either C. maculata eggs or A. pisum. Chrysoperla carnea fed C. maculata eggs developed into smaller adults, compared to adults reared as larvae on A. pisum, Ostrinia nubilalis (Hübner) eggs, or A. pisum alternated daily with O. nubilalis eggs. C. carnea did not complete preimaginal development on H. axyridis eggs. Cannibalism occurred more frequently between C. carnea third instars than between C. maculata fourth instars. When a C. carnea third instar was paired with a C. maculata fourth instar, more C. maculata were preyed upon by C. carnea, regardless of the herbivorous prey density. In the field these two predator species may negatively affect each other and reduce their suppression of pest densities.     

Effects of a juvenile hormone analogue, pyriproxyfen, on the apterous form of soybean aphid (Aphis glycines)

The soybean aphid, Aphis glycines Matsamura, is an eastern Asian soybean [Glycine max (L.) Merr.] pest which can reduce soybean yield. We determined the effects of pyriproxyfen, a juvenile hormone analogue, on development, mortality, longevity and fecundity of A. glycines under laboratory conditions. Distance Insect Growth Regulator, containing ∼11.2% pyriproxyfen, was applied at two concentrations, 50 and 150 mg/l, to first and fourth instar nymphs. When first or fourth instar A. glycines were treated with pyriproxyfen, some nymphs became supernumerary‐molted nymphs with 1–3 extra molts or were sterilized. Mortality of treated first instar nymphs was >68% greater than the control group and longevity was reduced by >40%. The higher concentration of pyriproxyfen reduced fecundity of first instar nymphs when they reached adulthood by ∼79%. Pyriproxyfen similarly affected fourth instar nymphs. Mortality of treated fourth instar nymphs was ≥15% greater than the control group and longevity was reduced by >24%. Both concentrations of pyriproxyfen lowered the fecundity of fourth instar nymphs by >27%. Pyriproxyfen also had other sublethal effects on fourth instar nymphs which became apparent when they molted to adulthood. In a few instances they developed wing pads and many produced dead, deformed or abnormal neonates that lacked appendages.     

Search for a sensitive stage for aposymbiosis induction in Culex pipiens pipiens by antibiotic treatment of immature stages

The elimination of symbiotic Wolbachia pipientis from Culex pipiens pipiens was studied by exposing the larvae or pupae to chlortetracycline hydrochloride for different lengths of time and for different stages in the life cycle. The effect of the antibiotic was cumulative. The longer the immature stages were treated, the poorer was the hatching rate of their eggs when they became adults. Larvae reared in antibiotic from the beginning of first, second, or third instar developed into adults with 100% hatching failure. If the insects were reared in the antibiotic from the beginning of the fourth instar only, about one-third of their eggs hatched. Rearing the immatures in antibiotic for single instars demonstrated that the ultimate deleterious effects were essentially the same for all stages, indicating that there is no uniquely sensitive stage for destroying the rickettsia. Many of the unhatched eggs contained fully developed, but dead, embryos.     

Effects of two biorational insecticides, spinosad and methoxyfenozide, on Spodoptera littoralis (Lepidoptera: Noctuidae) under laboratory conditions

The toxicity of two biorational insecticides, spinosad (Tracer) and methoxyfenozide (RH-2485), was tested against eggs, larvae, and pupae of the noctuid Spodoptera littoralis (Boisduval). In the first experiment, filter paper circles containing egg masses of two different age classes, young (<24 h old) and old (24-48 h old), were dipped in different concentrations of each insecticide diluted in either water or acetone. No ovicidal activity was recorded when insecticides were diluted in water. In contrast, when insecticides were diluted in acetone, both egg age classes generally showed a concentration-dependent response for both compounds. Mortality of larvae that hatched from both egg age classes was significantly increased, compared with control larvae, at all concentrations of both insecticides when diluted in water or acetone alike. The prevalence of mortality was similar with each insecticide. In the second experiment, third instars of S. littoralis were fed semisynthetic diet containing different concentrations of both insecticides. According to LC50 values, no significant differences were observed between spinosad (2.11 mg [AI]/kg diet) and methoxyfenozide (3.98 mg [AI]/kg diet) after 48 h of treatment, based on the overlap of 95% CL. Toxic effects on the mortality of pupae, adult emergence, and the prevalence of deformed adults after topical application on young pupae also were examined. Only methoxyfenozide caused pupal mortality and deformed adults. Our results suggest that spinosad and methoxyfenozide are potentially potent compounds for control of S. littoralis.     

Baseline susceptibility and development of resistance to pyriproxyfen in Bemisia argentifolii (Homoptera: Aleyrodidae) in Arizona

Pyriproxyfen (Knack) was registered in Arizona cotton, as the crucial component of a resistance management plan, to control whitefly Bemisia argentifolii (Bellows & Perring) in 1996. A statewide monitoring program was implemented at the same time to detect and monitor whitefly resistance to this novel insecticide. Bioassays involving dipping of leaves infested with whitefly eggs showed that all Arizona whiteflies tested were highly susceptible to pyriproxyfen in 1996. The LC50 estimates were in the range of 0.0020-0.0067 microg (AI)/ml. Two diagnostic pyriproxyfen concentrations, 0.01 and 0.1 microg (AI)/ml, were established for efficient identification of resistant whiteflies. No resistance to pyriproxyfen was detected in whiteflies in statewide surveys conducted in 1997 and 1998. Mean mortality at 0.01 microg (AI)/ml dropped significantly, and survivors were detected for the first time at 0.1 microg (AI)/ml in 1999, the fourth year of use of pyriproxyfen in Arizona cotton. Among the five cotton locations monitored each year since 1996, four of them had whiteflies with significantly reduced susceptibility to pyriproxyfen in 1999. Similarly, reduced susceptibility to pyriproxyfen was detected in whiteflies collected from fall melons and greenhouses in 1999. Although there have been no reports of field failures of pyriproxyfen in Arizona cotton, the reduced susceptibility of whiteflies from statewide survey in 1999 was significant. The results may indicate the development of an early stage of resistance to pyriproxyfen, and the findings should serve as early warning and substantiation of the high resistance risk of pyriproxyfen.     

Susceptibility of the predatory stinkbug <Emphasis Type="Italic">Picromerus bidens</Emphasis> to selected insecticides

The Palaearctic stinkbug Picromerus bidens L. (Heteroptera: Pentatomidae) has been considered as a potential biocontrol agent of several defoliator pests in various agricultural and forest ecosystems. It may therefore be a valuable alternative for the Nearctic pentatomid Podisus maculiventris (Say) (Heteroptera: Pentatomidae), the augmentative use of which has largely been abandoned in Europe given its possible environmental impact as an exotic polyphagous predator. However, no study has yet documented the impact of insecticides on P. bidens, which is essential to evaluate the possible combination of this predatory pentatomid with current insecticide applications in integrated pest management (IPM) programmes. This study reports on laboratory experiments investigating the susceptibility of P. bidens to five insecticides with different modes of action: the pyrethroid deltamethrin, the diacylhydrazine methoxyfenozide, the juvenile hormone mimic pyriproxyfen, the spinosyn spinosad, and the neonicotinoid imidacloprid, all of which are used to control defoliator pests. Fourth-instar nymphs and female adults of the predator were exposed to formulated materials of the insecticides by residual contact. Methoxyfenozide and spinosad did not cause significant mortality to 4th instars and female adults of P. bidens. In contrast, deltamethrin and imidacloprid were harmful to nymphs and adults of the predator, with LC₅₀ values ranging between 1.5 and 9.9 mg a.i./l. Pyriproxyfen was toxic to 4th instars with an LC₅₀ value of 13.9 mg a.i./l but did not affect female adults. Reproduction and longevity of P. bidens were not adversely affected when the predator was exposed to field concentrations of spinosad, methoxyfenozide, or pyriproxyfen, or sublethal concentrations (around LC₁₀) of deltamethrin and imidacloprid. The results from residual contact experiments suggest that methoxyfenozide, spinosad, and to a lesser extent, pyriproxyfen may be compatible with P. bidens in an IPM programme. Further experiments assessing food chain toxicity of these compounds should offer a more complete picture of their selectivity.     

Toxicity of diflubenzuron and pyriproxyfen to the predatory bugPodisus maculiventris

The susceptibility of the predatory pentatomidPodisus maculiventris (Say) to the insect growth regulators (IGRs) diflubenzuron and pyriproxyfen was investigated in the laboratory. Fifth-instar nymphs were exposed to formulated materials of each compound via direct contact, residual contact and ingestion. Diflubenzuron was harmless toP. maculiventris by direct and residual contact, but was highly toxic when ingested via drinking water. Pyriproxyfen caused severe deformities at ecdysis whatever the method of exposure. Exposure of fifth instars to sublethal concentrations (around LC₁₀) of both compounds had no adverse effects on reproduction of emerging adults. The data suggest that the use of these IGRs in the integrated management of insect pests should be evaluated with caution.     

Effects of bio-pesticides on Eretmocerus warrae (Hym., Aphelinidae), a parasitoid of Bemisia tabaci (Hom., Aleyrodidae)

The sweet potato whitefly Bemisia tabaci (WF) can be controlled by two commercial neem products, NeemAzal-T/S^® (1% azadirachtin) for foliar application, and NeemAzal-U (17% azadirachtin) for soil application, alongwith two biorational products of microbial origin, Abamectin (avermectin) and Success^® (spinosad). Side effects of these products were tested in a laboratory bioassay against a native aphelinid, Eretmocerus warrae (EW). Eggs and early larval instars of the parasitoid, commonly found outside the host body, were highly susceptible to foliar spray of neem with only 8%, 18% and 55% emergences of adults from treated eggs. larval and pupal stages respectively at recommended dose-rates of 5 ml/l and 1%, 8% and 40% at twice recommend dose-rate (10 ml/l). Soil application with NeemAzal-U marginally affected EW. At highest tested dose-rate of 3.0 g/l, 46%, 64% and 81% emergence was recorded after treatement of plants harbouring WF parasitized by egg, larval and pupal stages of EW respectively. In contrast to neem application, Success^® and Abamectin caused high mortality in development stages of the parasitoids. In particular, abamectin was highly toxic to the parasitoids with less than 1% emergence from either of the three development stages if treated with 1–2 ml/l.     

Influence of the entomopathogenic fungus Isaria fumosorosea on Axinoscymnus cardilobus (Coleoptera: Coccinellidae) under laboratory conditions

Effects of entomopathogenic fungus Isaria fumosorosea on biological characteristics and life table parameters of Axinoscymnus cardilobus, a predator of whiteflies, were studied using five different conidial concentrations under laboratory conditions. Non-significant differences were observed among different fungal concentrations on the percent survival of all immature stages. The survival of A. cardilobus on different host plants did not differ significantly. The prey consumption of third instar A. cardilobus on Bemisia tabaci treated with different fungal concentrations differed significantly at different time intervals. The developmental periods for all immature stages (from eggs, first, second, third, fourth instar nymph and pupae up to emergence) among the treatments were not statistically significant when compared to that of control. In the present study, fecundity, longevity, egg viability and life table parameters of females were not statistically significant over the different concentrations. It can be concluded that control strategies tested are compatible to a greater extent and incorporation of these have promising prospects for control of whitefly.     

The differential mortality at various life stages of the greenhouse whitefly,Trialeurodes vaporariorum (Homoptera: Aleyrodidae), by infection with the fungus Aschersonia aleyrodis (Deuteromycotina: Coelomycetes)

The parasitoid Encarsia formosa is commonly applied to control the greenhouse whitefly Trialeurodes vaporariorum in glasshouse tomatoes and cucumbers. Nevertheless, in some cases the control capacity of this natural enemy is insufficient and an additional selective pest-suppressing agent is desirable. The entomopathogenic fungus Aschersonia aleyrodis was applied to cucumber plants carrying whiteflies in different developmental stages. After spraying each leaf with 2 ml of spore suspension (4 × 10⁶ spores/ml) the plants were kept at 100% RH for 24 hr; thereafter the humidity was lowered to 70% RH at 20°C and the photoperiod was 16 hr. Treated eggs did not become infected, but larvae that hatched from these eggs and settled on the treated abaxial leaf surface were infected at the same rate and to the same degree as treated first instar larvae. This suggests that the spores persist for at least 7 days. The final percentages of infection over all instars when treated as young eggs, old eggs, and first larval instars were 94, 93, and 90%, respectively. The final percentages of infection when treated as third and fourth larval instars and prepupae were 76, 28, and 12%, respectively. The older instars were less susceptible and adults were seldom infected by the fungus. Several applications of A. aleyrodis as a microbial insecticide are needed to achieve sufficient control of whitefly populations in glasshouses.     

Endozoochory by ducks: influence of developmental stage of Bythotrephes diapause eggs on dispersal probability

Abstract. This paper evaluates whether the recent expansion of Bythotrephes longimanus Leydig (Crustacea: Onychopoda) may be a result of endozoochorous avian dispersal. In three experiments, we investigated the survival of diapause eggs in newly produced and end-of-winter developmental stages after their passage through the digestive tract of four species of ducks. Resistance of eggs to digestion was low for both developmental stages (< 12%). Most eggs (67–95%) were recovered by four hours after ingestion, with a longer maximum retention time for newly produced (22 h) than end-of-winter eggs (4–6 h). Ingestion had a detrimental effect on viability: only eggs retrieved one hour after ingestion hatched and the proportion of those ingested that produced viable neonates was low (0.5% for newly produced and 0.3–3% for end-of-winter eggs). We conclude that the probability of endozoochorous dispersal by individual ducks is low but becomes significant when considering the thousands of ducks moving among wetlands. Endozoochorous dispersal of B. longimanus would most likely involve the transport of newly produced diapause eggs from north to south, during the autumn migration of ducks. Based on flight speed estimates of ducks we estimate dispersal probability to drop sharply at distances over 60–80 km.     

Effects of pyriproxyfen and buprofezin on immature development and reproduction in the stable fly*

The stable fly, Stomoxys calcitrans (L.) (Diptera: Muscidae), is one of the most significant biting flies that affect cattle. The use of traditional insecticides for stable fly control has only a limited success owing to the insect's unique feeding behaviours and immature development sites. A laboratory study was conducted to evaluate the effects of two insect growth regulator (IGR) products, pyriproxyfen and buprofezin, on the development of the immature stages of the stable fly and the effects of pyriproxyfen on oviposition and egg hatch. Both pyriproxyfen and buprofezin had significant inhibitory effects on immature development. The LC₅₀s of pyriproxyfen and buprofezin were 0.002 and 18.92 p.p.m., respectively. Topical treatment of adult females with different doses of pyriproxyfen had significant negative effects on both female oviposition and egg hatching when 1‐ and 3‐day‐old females were treated, and the effects were dose dependent. A significant reduction in the mean number of eggs laid was observed only at the highest pyriproxyfen dose (8 µg/fly) and egg hatch was unaffected by pyriproxyfen treatment when 5‐day‐old females were treated. Results from the present study indicate that pyriproxyfen has the potential to be used as part of an integrated stable fly management programme.