Ionizing irradiation quarantine treatment against oriental fruit moth (Lepidoptera: Tortricidae) in ambient and hypoxic atmospheres

Oriental fruit moth, Grapholita molesta (Busck), is a pest of many rosaceous temperate fruits, including pomes, Malus spp., and stone fruits, Prunus spp., in much of the world. However, some areas are free of the pest, and shipments of fruit hosts from infested to noninfested areas may be regulated. Current quarantine treatments for oriental fruit moth include methyl bromide fumigation and cold storage for several weeks. Methyl bromide use is being restricted because it is a stratospheric ozone-depleting substance, and alternatives are sought. Cold is not tolerated by many hosts of oriental fruit moth. The objective of this research was to develop irradiation quarantine treatments against the pest under ambient and hypoxic storage conditions because some hosts of oriental fruit moth are stored in hypoxic atmospheres, and hypoxia is known to lessen the effects of irradiation. In ambient atmospheres, no adults emerged from 58,779 fifth instars (the most radiotolerant stage present in fruit) irradiated with a target dose of 200 Gy (195-232 Gy measured). In atmospheres flushed with nitrogen, 5.3% of adults emerged from 44,050 fifth instars irradiated with a target dose of 200 Gy (194-230 Gy measured), but they died at a faster rate than control adults and without laying eggs. A dose of 232 Gy (the maximum recorded when 200 Gy was targeted) is recommended to disinfest any fruit of oriental fruit moth under ambient and hypoxic atmospheres.     

Effect of irradiation on Mexican leafroller (Lepidoptera: Tortricidae) development and reproduction

The effects of irradiation on egg, larval, and pupal development, and adult reproduction in Mexican leafroller, Amorbia emigratella Busck (Lepidoptera: Tortricidae), were examined. Eggs, neonates, early instars, late instars, early pupae, and late pupae were irradiated at target doses of 60, 90, 120, or 150 Gy, or they were left untreated as controls in replicated factorial experiments. Survival to the adult stage was recorded. Tolerance to radiation increased with increasing age and developmental stage. A radiation dose of 90 Gy applied to neonates and early instars prevented adult emergence. A dose of 150 Gy was not sufficient to prevent adult emergence in late instars or pupae. The effect of irradiation on sterility was examined in late pupae and adult moths. For progeny produced by insects treated as late pupae, a total of three out of 3,130 eggs hatched at 90 Gy, 0 out of 2,900 eggs hatched at 120 Gy, and 0 out of 1,700 eggs hatched at 150 Gy. From regression analysis, the dose predicted to prevent egg hatch from the progeny of irradiated late pupae was 120 Gy, with a 95% confidence interval of 101-149 Gy. The late pupa is the most radiotolerant stage likely to occur with exported commodities; therefore, a minimum absorbed radiation dose of 149 Gy (nominally 150 Gy) has potential as a quarantine treatment. Reciprocal crosses between irradiated and unirradiated moths demonstrated that males were more radiotolerant than females. Irradiation of female moths at a target dose of 90 Gy before pairing and mating with irradiated or unirradiated males resulted in no viable eggs, whereas irradiated males paired with unirradiated females produced viable eggs at 90 and 150 Gy.     

Irradiation of adult Epiphyas postvittana (Lepidoptera: Tortricidae): egg sterility in parental and F1 generations

Adult Epiphyas postvittana Walker were irradiated using a Cobalt 60 source to determine the dose needed to achieve complete egg sterility of mated female moths, and egg sterility of female moths mated to F1 generation males. Adult male and female E. postvittana were irradiated at 100, 200, 250, and 300 Gy and their fertility (when crossed with normal moths) was compared with nonirradiated moths. Viable progeny (determined by egg hatch) were found at doses of 100 and 200 Gy, but very little at 250 and 300 Gy. In particular, there was no survival of female progeny into the F1 generation. Males irradiated at 250 and 300 Gy had very low egg eclosion rates (2.25 and 1.86% at 250 and 300 Gy, respectively) when mated with normal females. The F2 generation from those male progeny had a mean percent hatched of < 1.02%. Based on our results, a dose of 250-300 Gy is recommended for irradiation of E. postvittana adults used for sterile insect technique (SIT) if sterility of parental moths is the desired outcome. Our data also suggests that inclusion of F1 hybrid sterility rather than parental generation sterility into programs using the SIT may allow for doses lower than what we have reported, especially during initial phases of an eradication program where increase fitness of moths might be desirable. Further research is needed to verify the use of F1 hybrid sterility in light brown apple moth SIT programs.     

Phytosanitary irradiation of Liriomyza trifolii (Diptera: Agromyzidae)

Agromyzid leafminers are economic and quarantine pests of a variety of vegetables, flowers, and ornamental foliage. Methyl bromide fumigation is often used as a phytosanitary treatment when quarantined agromyzids are found in shipped commodities; alternative treatments are sought. Ionizing radiation is a viable alternative that is increasing in use worldwide. A dose of 400 Gy is accepted by USDA-APHIS for all insects (except Lepidoptera pupae and adults) on all commodities. Efforts to lower this dose and make it acceptable to other countries involve determining radiotolerance of families of major quarantine pests. Agromyzidae is one such family for which no useful information on radiotolerance exists. This research sought to determine the dose required to control a major agromyzid pest, Liriomyza trifolii (Burgess) and was performed on L. trifolii collected in Weslaco, TX, reared on Phaseolus vulgaris L. and Capsicum annuum L. and irradiated in the late puparial stage. The measure of efficacy was prevention of F1 mine formation. Puparia collected from Gossypium hirsutum L. and reared on P. vulgaris were more radiotolerant than those collected and reared on C. annuum. A dose of 214 Gy may prevent F1 mine formation of L. trifolii. This research used a variation of probit analysis where the direct response of the treated individual is not measured, but the response of the F1 generation is. This type of analysis is useful in phytosanitary irradiation research where the measure of efficacy often involves a response of the F1 generation.     

Susceptibility of potato plants grown from tubers irradiated with stimulation doses of gamma irradiation to potato tuber moth, Phthorimaea operculella Zeller (Lep., Gelechiidae)

The feeding behaviour of potato tuber moth, Phthorimaea operculella Zeller (Lep., Gelechiidae), reared on leaves and tubers of potato plants, which were irradiated as seed (tubers) with stimulation doses of gamma irradiation (1, 3, 5 and 10 Gy), was studied. Significant differences in the larvae and pupae developmental time, pupal weight, mortality, fecundity and percentage egg hatch, were observed between insects fed on plants which resulted from the irradiated seeds and those of the control. It appears that leaves of potato plants grown from irradiated seeds particularly those of 3 Gy, became more attractive to the larvae, although the resulting tubers, with the exception of those of 10 Gy, became more resistant to potato tuber moth. Storing the tubers at ambient temperature conditions affected the degree of larval sensitivity. The leaves and tubers of 10 Gy-irradiated seeds became more suitable for insect development, indicating that the later dose may inhibit the production of secondary plant metabolities and chemical compounds.     

Life history attributes of Indian meal moth (Lepidoptera: Pyralidae) and Angoumois grain moth (Lepidoptera: Gelechiidae) reared on transgenic corn kernels

The Indian meal moth, Plodia interpunctella (Hübner), and Angoumois grain moth, Sitotroga cerealella (Olivier), are two globally distributed stored-grain pests. Laboratory experiments were conducted to examine the impact that corn (Zea mays L.) kernels (i.e., grain) of some Bacillus thuringiensis Berliner (Bt) corn hybrids containing CrylAb Bt delta-endotoxin have on life history attributes of Indian meal moth and Angoumois grain moth. Stored grain is at risk to damage from Indian meal moth and Angoumois grain moth; therefore, Bt corn may provide a means of protecting this commodity from damage. Thus, the objective of this research was to quantify the effects of transgenic corn seed containing CrylAb delta-endotoxin on Indian meal moth and Angoumois grain moth survival, fecundity, and duration of development. Experiments with Bt grain, non-Bt isolines, and non-Bt grain were conducted in environmental chambers at 27 +/- 1 degrees C and > or = 60% RH in continuous dark. Fifty eggs were placed in ventilated pint jars containing 170 g of cracked or whole corn for the Indian meal moth and Angoumois grain moth, respectively. Emergence and fecundity were observed for 5 wk. Emergence and fecundity of Indian meal moth and emergence of Angoumois grain moth were significantly lower for individuals reared on P33V08 and N6800Bt, MON 810 and Bt-11 transformed hybrids, respectively, than on their non-Bt transformed isolines. Longer developmental times were observed for Indian meal moth reared on P33V08 and N6800Bt than their non-Bt-transformed isolines. These results indicate that MON 810 and Bt-11 CrylAb delta-endotoxin-containing kernels reduce laboratory populations of Indian meal moth and Angoumois grain moth. Thus, storing Bt-transformed grain is a management tactic that warrants bin scale testing and may effectively reduce Indian meal moth and Angoumois grain moth populations in grain without application of synthetic chemicals or pesticides.     

Radiation biology and inherited sterility of light brown apple moth (Lepidoptera: Tortricidae): developing a sterile insect release program

The radiation biology of two geographically isolated populations of the light brown apple moth [Epiphyas postvittana (Walker)] was studied in Australia and New Zealand as an initiation of a SIT/F1 sterility program. Pharate and < or = 2 d pre-emergence pupae were exposed to increasing radiation doses up to a maximum dose of 300 Gy. Fertility and other life history parameters were measured in emerging adults (parental) and their progeny (F1-F3 adults). Parental fecundity was significantly affected by increasing irradiation dose in pharate pupae only. For both populations, parental egg fertility declined with increasing radiation. This was most pronounced for the irradiated parental females whose fertility declined at a higher rate than of irradiated males. At 250 Gy, females < or = 2 d preemergence pupae produced few larvae and no adults at F1. No larvae hatched from 250 Gy-irradiated female pharate pupae. At 300 Gy, males still had residual fertility of 2-5.5%, with pharate pupae being the more radio-sensitive. Radiation-induced deleterious inherited effects in offspring from irradiated males were expressed as increased developmental time in F1 larvae, a reduction in percent F1 female survival, decreased adult emergence and increased cumulative mortality over subsequent generations. Males irradiated at > or = 150 Gy produced few but highly sterile offspring at F1 and mortality was > 99% by F2 egg.     

Potential for controlling codling moth Cydia pomonella (Linnaeus) (Lepidoptera: Tortricidae) in Argentina using the sterile insect technique and egg parasitoids

Codling moth is the main pest affecting apples and pears worldwide. Most pest control strategies used against this insect have relied on the use of broad‐spectrum insecticides which have led to non‐desirable effects like pesticide resistance, residues in the environment, human health concerns and the reduction of access to international markets. Therefore, alternative pest control strategies that would result in sustainable fruit production systems while taking care of the environment are strongly promoted. The use of the sterile insect technique has proven to be a valuable pest control tactic within area‐wide integrated pest management strategies, and its synergistic effect for Lepidoptera pests when combined with other biological control tactics such as parasitoids has been documented. The purposes of this research were to evaluate the response of an Argentinean codling moth strain to a sub‐sterilizing radiation dose of 100 Gy and to assess the acceptability and suitability of sterile codling moth eggs by the egg parasitoids, Trichogramma cacoeciae (Marchal) and Trichogramma nerudai (Pintureau and Gerding). Irradiated female moths survived better than irradiated male moths and non‐irradiated male and female moths. Also, the fecundity of irradiated female moths was reduced by more than 30% as compared to non‐irradiated ones whereas their fertility was close to zero. The F₁ generation was male biased with a lower fertility (inherited sterility) than the parental generation. Trichogramma cacoeciae and T. nerudai parasitized both fertile and sterile eggs. However, there was a significant reduction in acceptability for sterile eggs. Trichogramma nerudai parasitized more eggs than T. cacoeciae, but egg acceptability for this species was proportionally lower than for T. cacoeciae especially on eggs oviposited by irradiated females. Development to adult of both parasitoids species was not substantially affected by the origin of the eggs and the wasps had acceptable levels of adult emergence, survival and fecundity. These results provided useful information on the potential for controlling the codling moth using egg parasitoids and the sterile insect technique in Argentina.     

Effect of electron beam irradiation on developmental stages of Plutella xylostella (Lepidoptera: Plutellidae)

The effect of electron beam irradiation on each developmental stage of diamondback moth, Plutella xylostella L. (Lepidoptera: Plutellidae), was examined. Eggs, larvae, pupae, and adults were irradiated at target doses of 30, 50, or 100 Gy or they were left untreated as controls in replicated experiments. When eggs and pupae were irradiated with 100 Gy, emergence rates greatly decreased and, although some adults laid eggs, they did not hatch. Egg hatching of irradiated larvae and adult decreased with increasing irradiation doses. However, electron beam irradiation did not kill P. xylostella directly. Adult longevity was not affected. Reciprocal crosses between irradiated and unirradiated moths demonstrated that females were more radiosensitive than males in hatchability; however, the difference was not significant. In addition, electron beam-irradiated larvae showed typical DNA fragmentation in a dose-dependent manner compared with cells from unirradiated larvae. Our findings suggest that electron beam irradiation induces abnormal development and reproduction of P. xylostella; therefore, it may contribute to effective disinfestation and quarantine treatments of P. xylostella.     

Effect of irradiation on female painted apple moth Teia anartoides (Lep., Lymantriidae) sterility and attractiveness to males

Abstract:  Live female painted apple moths are being used to monitor the distribution of this invasive species in Auckland as part of a major eradication effort, and the goal of this project was to develop a method to minimize the risk of unwanted live insect propagation from the trapping programme as a result of vandalism or 'eco-terrorism'. Female pupae were irradiated with a range of doses and their egg viability assessed, and also tested to determine the impact of irradiation on male moth catch in the field. Female painted apple moth pupae, irradiated at a range of doses from 100 to 500 Gy, were placed in cages in traps at 10 m spacings from non-irradiated females, near a central release site of irradiated males. Untreated control females alternated along orthogonal transects with irradiated females. The results indicated no significant effect of female irradiation on catch of males. There was no correlation between dose and catch, within the range of exposures tested. There was a very low hatch rate of eggs from females irradiated at all doses tested (100–500 Gy). These results suggest that irradiated females could be used in traps to reduce potential risks of deliberate spread of the unwanted organism by activists, without affecting the effectiveness of monitoring males.     

Integration of nonchemical treatments for control of postharvest pyralid moths (Lepidoptera: Pyralidae) in almonds and raisins

We propose a treatment strategy combining an initial disinfestation treatment with one of three protective treatments as an alternative for chemical fumigation of almonds and raisins for control of postharvest insect populations. Initial disinfestation treatments using low oxygen controlled atmosphere (0.4% O2) were designed to disinfest product of field populations of pyralid moths; navel orangeworm, Amyelois transitella (Walker), in almonds and raisin moth, Cadra figulilella (Gregson), in raisins. The protective treatments were cold storage (10 degrees C), controlled atmosphere (5% O2) storage, and application of the Indianmeal moth granulosis virus, and were designed to prevent establishment of Indianmeal moth, Plodia interpunctella (Hübner). The initial disinfestation treatment was effective against laboratory populations of navel orangeworm and raisin moth. Efficacy of protective treatments was determined by exposure of commodities to laboratory Indianmeal moth populations at levels far higher than those found in commercial storage facilities. All three protective treatments prevented development of damaging Indianmeal moth populations as measured by pheromone trap catches and evaluation of product samples. Quality analysis by commercial laboratories showed that overall product quality for all protective treatments was maintained at levels acceptable by industry standards.     

Modeling the sterile insect technique for suppression of light brown apple moth (Lepidoptera: Tortricidae)

A population model was derived for light brown apple moth, Epiphyas postvittana (Walker) (Lepidoptera: Tortricidae), subject to the sterile insect technique (SIT). The model was parameterized from the literature and from recent laboratory studies conducted in New Zealand and Australia. Relationships were fitted for several model parameters that vary with irradiation dose, allowing the model to simulate effectively complete sterility at 300 Gy through inherited sterility occurring from lower doses. At 300 Gy, the model suggests that eventual population extinction is 95% probable when the ratio of released to wild males in monitoring traps exceeds 6.4. Higher overflooding rates would be required to achieve eradication more rapidly. The optimal release interval, in terms of minimizing the required rate of production of factory moths, is approximately weekly. There is little advantage in releasing males only compared with releasing both sexes. Female-only releases are unlikely to be a useful tool for inherited sterility eradication because there is no reduction in the fertility of F1 offspring. The critical release rate required to halt population increase declines with decreasing irradiation dose, but at doses of < 171 Gy there is a risk that irradiated-lineage moths may form a self-sustaining population, making eradication by SIT alone impossible. The model suggests that a dose of around 200 Gy may be optimal because the resulting inherited sterility would reduce by a third the number of factory moths required compared with 300 Gy.     

Gamma irradiation as a quarantine treatment for apples infested by codling moth (Lep., Tortricidae)

Abstract: Effects of gamma radiation on the fifth instar codling moth, Cydia pomonella (L.), larvae were examined. Mature larvae were exposed to a series of gamma radiation doses ranging from 50 to 250 Gy and survival to pupae and adults was examined. The results showed that pupation and adult emergence decreased with increasing radiation dose. The results also showed that diapausing larvae were more sensitive to irradiation treatment than non-diapausing larvae, and females were more sensitive than males. A dose of 150 Gy reduced adult emergence to less than 2% in non-diapausing larvae, while a dose of 200 Gy completely prevented it. Furthermore, none of the emerging moths exposed to a dose of 150 Gy were females; at 100 Gy dose, the percentage of females was less than 14%. Irradiating larvae in apple fruit in a small-scale laboratory experiment produced similar results. Tests in which >100 000 larvae (in the fifth instar) were irradiated in an artificial rearing medium with a dose of 200 Gy resulted in no adult emergence. Similar results were also obtained when >32 000 larvae in the same stage were exposed in apple fruit to the same dose. The results indicate that the use of ionizing radiation as a quarantine treatment for codling moth infested fruits is feasible and requires a relatively low dose.     

Developing the sterile insect technique for Cryptophlebia leucotreta (Lepidoptera: Tortricidae): influence of radiation dose and release ratio on fruit damage and population growth in field cages

The effect of radiation dose and different release ratios of treated (T) to untreated (U) Cryptophlebia leucotreta (Meyrick) (Lepidoptera: Tortricidae), on the incidence of fruit damage, the competitiveness of the treated males, and population growth was examined inside field cages. Navel orange trees were individually enclosed in large nylon mesh cages. Newly emerged adult moths treated with either 150 or 200 Gy of gamma radiation were released into the cages at ratios of 5T:1U or 10T:1U. The fruit was collected after 4 wk, and the number of damaged fruit and larval entries per cage were recorded for each treatment. Infested fruit was maintained in the laboratory until all emerging F1 progeny were collected and outcrossed to untreated moths of the opposite sex. Treatment had a significant effect on the mean number of larval entries and on the number of undamaged fruit per cage. The number of larval entries as well as the number of F1 progeny per cage decreased as the overflooding ratio increased. A significant reduction in egg hatch was observed in the progeny of crosses between F1 females or F1 males originating from the treatment cages compared with crosses of F1 moths originating from the control cages. The lowest mean number of fertile F1 adult females and males was obtained from the 150 Gy and 10T:1U ratio treatment. This treatment also showed the lowest per generation rate of increase (< 1 from the parental [P1] to the F1 generation), suggesting that growth in the fertile population would have been prevented if releases of treated moths at this dose and ratio were maintained in the field.     

Comparative fitness of irradiated light brown apple moths (Lepidoptera: Tortricidae) in a wind tunnel, hedgerow, and vineyard

Light brown apple moth, Epiphyas postvittana (Walker) (Lepidoptera: Tortricidae), is the target of the sterile insect technique, but reduced moth fitness from irradiation lowers the effective overflooding ratio of sterile to wild moths. New measures of insect quality are being sought to improve field performance of irradiated insects, thus improving the cost effectiveness of this technique. Male pupae were irradiated at intervals between 0 and 300 Gy, and adult flight success was assessed in a wind tunnel equipped with flight track recording software. A dose response was evident with reduced successful search behaviors at higher irradiation doses. Irradiation at 250 Gy reduced arrival success to 49% of untreated controls, during 2-min assays. Mark-release-recapture of males irradiated at 250 Gy indicated reduced male moth recapture in hedgerows (75% of control values of 7.22% +/- 1.20 [SEM] males recaptured) and in vineyards (78% of control values 10.5% +/- 1.66% [SEM] recaptured). Males dispersed similar distances in both habitats, and overflooding ratios dropped off rapidly from the release point in both landscapes. Transects of traps with central releases proved to be an efficient method for measuring the quality of released males. Relative field performance of moths was greater than suggested by wind tunnel performance, which could be due to time differences between the two assays, two-minute wind tunnel tests compared with days in the field treatments. Release strategies involving ground releases should consider the effect of limited postrelease dispersal. Aerial release could solve this problem and warrants investigation.     

Survival of indianmeal moth and navel orangeworm (Lepidoptera: Pyralidae) at low temperatures

Concerns over insect resistance, regulatory action, and the needs of organic processors have generated renewed interest in developing nonchemical alternative postharvest treatments to fumigants used on dried fruits and nuts. Low-temperature storage has been identified as one alternative for the Indianmeal moth, Plodia interpunctella (Hiibner), and navel orangeworm, Amyelois transitella (Walker) (Lepidoptera: Pyralidae), common postharvest pests in California dried fruits and nuts. The response of eggs, nondiapausing larvae, and pupae of both species to exposure to low temperatures (0, 5, and 10 degrees C) was evaluated. Eggs of both species were the least tolerant of low temperatures. At 0 and 5 degrees C, pupae were most tolerant, but at 10 degrees C, nondiapausing larvae of both species were most tolerant, with lethal time (LT)95 values of 127 and 100 d for Indianmeal moth and navel orangeworm, respectively. The response of diapausing Indianmeal moth larvae to subfreezing temperatures also was evaluated. Diapausing larvae were very cold tolerant at -10 degrees C, with LT95 values of 20 and 17 d for long-term laboratory and recently isolated cultures, respectively. Diapausing larvae were far less tolerant at lower temperatures. At -15 degrees C, LT95 values for both cultures were <23 h, and at -20 degrees C, LT95 values were <7 h. Refrigeration temperatures of 0-5 degrees C should be useful in disinfesting product contaminated with nondiapausing insects, with storage times of 3 wk needed for adequate control. Relatively brief storage in commercial freezers, provided that the temperature throughout the product was below -15 degrees C for at least 48 h, also shows potential as a disinfestation treatment, and it is necessary when diapausing Indianmeal moth larvae are present.     

Quality of mass-reared codling moth (Lepidoptera: Tortricidae) after long-distance transportation: 1. Logistics of shipping procedures and quality parameters as measured in the laboratory

The sterile insect technique (SIT) is a proven effective control tactic against lepidopteran pests when applied in an areawide integrated pest management program. The construction of insect mass-rearing facilities requires considerable investment and moth control strategies that include the use of sterile insects could be made more cost-effective through the importation of sterile moths produced in other production centers. For codling moth, Cydia pomonella (L.) (Lepidoptera: Tortricidae), this is an attractive option because mating studies have confirmed the absence of mating barriers between codling moth populations from geographically different areas. To assess the feasibility of long-distance transportation of codling moths, pupae and adult moths were transported in 2004 from Canada to South Africa in four shipments by using normal commercial transport routes. The total transport time remained below 67 h in three of the consignments, but it was 89 h in the fourth consignment. Temperature in the shipping boxes was fairly constant and remained between -0.61 and 0.16 degrees C for 76.8-85.7% of the time. The data presented indicate that transporting codling moths as adults and pupae from Canada to South Africa had little effect on moth emergence, longevity, and ability to mate, as assessed in the laboratory. These results provide support to the suggestion that the STT for codling moth in pome fruit production areas might be evaluated and implemented by the importation of irradiated moths from rearing facilities in a different country or hemisphere.     

Irradiation disinfestation of apple maggot (Diptera: Tephritidae) in hypoxic and low-temperature storage

Apple maggot, Rhagoletis pomonella (Walsh), is a quarantine pest of apples, Malus domestica Borkhausen, and pears, Pyrus communis L., shipped from much of the United States and Canada. As such, these fruits shipped from infested areas to uninfested areas must undergo a quarantine disinfestation treatment. The objective of this research was to develop irradiation quarantine treatments against apple maggot considering that fruit hosts may be stored under hypoxic or cold conditions when they are irradiated. Hypoxia increased from 30.5 to 35.7 Gy (17%) the estimated dose to achieve 99% prevention of the full pupal stage from irradiated third instars in apples compared with ambient atmospheres. However, 50 Gy completely prevented the full pupa in 22,360 and 15,530 third instars, respectively, irradiated in apples in ambient and hypoxic atmospheres. There was no difference in development to the full pupal stage in apple maggot third instars held at 1 or 24 degrees C when irradiated with 20 Gy. Because the maximum dose measured when 50 Gy was sought was 57 Gy, the latter should be the dose recommended for quarantine disinfestation of host fruits of the apple maggot. Apples and pears tolerate much higher doses.     

Effect of rearing strategy and gamma radiation on fecundity and fertility of codling moth Cydia pomonella (Linnaeus) (Lepidoptera: Tortricidae)

The codling moth Cydia pomonella (Linnaeus) (Lepidoptera: Tortricidae) is a serious pest of pome fruit worldwide. In an effort to reduce the use of pesticides to control this pest, the sterile insect technique (SIT) is used or considered for use as a component of area‐wide integrated pest management programmes. Rearing codling moths through diapause has been shown to improve the competitiveness of sterile moths released in orchards, and provides management alternatives that would allow mass‐rearing facilities to increase their yearly production of sterile moths. Because radiosensitivity in insects can be influenced by numerous biological factors, laboratory tests were conducted to examine whether the response to increasing doses of radiation, as expressed in the fecundity and fertility of cohorts of moths, is similar for adult moths mass‐reared through diapause or through standard (non‐diapause) production protocols. Our data revealed that the effect of increasing doses of radiation on fecundity and fertility of codling moths reared through both rearing strategies was similar. In the case of fertility, this is a particularly important finding for the expanded application of codling moth SIT. If mass‐rearing facilities use year‐round diapause rearing, the dose required to treat the insects prior to release will be similar to that used when codling moths are reared through standard production protocols.     

Ecology of the coprophagous moth Trisyntopa neossophila Edwards (Lepidoptera: Oecophoridae)

Trisyntopa neossophila Edwards (Lepidoptera: Oecophoridae) is an unusual moth whose breeding cycle is closely synchronised with a termite mound nesting parrot of northern Australia; the hooded parrot ( Psephotus dissimilis Collet). T. neossophila is one of three coprophagous, nest dwelling moths in the genus Trisyntopa Lower 1918. True coprophagy is rare in the Lepidoptera, although some species occasionally consume faeces to gain rare nutrients. We present observations of the life cycle of T. neossophila , a moth that lays its eggs in the nest of a hooded parrot, so that larvae hatch in synchrony with the hatching of the parrot's eggs. The larvae spend their larval period in the nest and exclusively consume the excrement of the nestling parrots. When the parrot chicks fledge, the larvae move to the walls of the nest cavity to pupate, emerging the following wet season to repeat the process during the next parrot breeding season.