Use Of Sterile Insect Technique Research Articles

Potential use of sterile insect technique (SIT) against the Indian meal moth, Plodia interpunctella

Indian meal moth, Plodia interpunctella (Hübner) is one of the most important stored products pests in the world. In Bangladesh, annual losses to different stored commodities occurs more than 20%. In this research, an environmentally safe & species specific method i.e. Sterile Insect Technique (SIT) was applied as a part of integrated pest management approach. This experiment was done by implementing gamma irradiation (Cobalt-60) for sterilization of Indian meal moth to suppress the reproductive potential of the moth. The effects were more significant in F1 early progeny than parental generation because it was possible to suppress the egg production, hatchability & finally adult emergence successfully in F1 generation. The dose of radiation required to prevent fecundity of Plodia interpunctella from irradiated adults was 400 Gy in parental generation (P), whereas it was 300Gy & 400Gy in F1 generation in the present study. The hatchability would be prevented by the cross schedule of treated male with treated female (TM x TF). 400 Gy dose would be sufficient to control the hatchability of Indian meal moth both in P & F1 generation. Higher doses of radiation had a significant effect on adult emergence in F1 early progeny of the moth. Surprisingly, the number was zero for the cross schedule of normal female with treated male (NF x TM) & treated male with treated female (TM x TF) at all the selected doses except 50Gy in F1 early progeny in the present study. The 300Gy & 400Gy doses used in the present experiment would be sufficient to control the population of Indian meal moth.

Effect of the timing of pupal irradiation on the quality and sterility of oriental fruit flies (Diptera: Tephritidae) for use in Sterile Insect Technique

Effect of the timing of pupal irradiation on the quality and sterility of oriental fruit flies (Diptera: Tephritidae) for use in Sterile Insect Technique

Evaluating Flight Performance of Mass-Reared and Irradiated Navel Orangeworm (Lepidoptera: Pyralidae) for Sterile Insect Technique.

Navel orangeworm (Pyralidae: Amyelois transitella) is a key pest of almonds and pistachios in California. Moths directly infest nuts which leads to reduced crop yield and quality, and infestation can predispose nuts to fungal pathogens that produce aflatoxins. While several integrated pest management strategies have been developed for A. transitella, studies have recently been initiated to explore the use of sterile insect technique (SIT) as an additional control tool. Mass-rearing, sterilization, and transportation methods originally developed for Pectinophora gossypiella (Lepidoptera: Gelechiidae) are currently being used for production of A. transitella in a mass-rearing facility, but the impacts of these processes on performance of A. transitella remain unclear. In this study, computerized flight mills were used to evaluate multiple flight parameters of mass-reared and irradiated A. transitella males and females relative to non-irradiated mass-reared moths and two strains of locally reared moths which were neither mass-reared nor irradiated. Mass-reared non-irradiated females performed similarly to both strains of locally reared females, flying a mean 9.4-11.8 km per night, whereas mass-reared and irradiated males and mass-reared non-irradiated males all flew shorter distances, in the range of 3.0-6.7 km per night. All of the mass-reared moths compared to locally reared moths had significantly more non-fliers that did not engage in more than two minutes of continuous flight. Findings from this study suggest that mass-rearing conditions reduce A. transitella flight capacity, while irradiation interacts with moths in a sex-specific manner.

Effects of temperature and relative humidity on mating and survival of sterileDrosophila suzukii

AbstractDrosophila suzukii(Matsumura) (Diptera: Drosophilidae) is a widely distributed pest species of soft‐skinned fruits. Recent studies suggest the use of sterile insect technique (SIT) as a control method for this species; however, many factors can impact effectiveness of a SIT programme, including the environmental conditions. Environmental condition is critical at the time of the release and in the days afterwards, since it may impact sterile insects’ survival and ability to mate. Thus, we verified the influence of temperature and relative humidity on mating and survival of fertile and sterileD. suzukii, when insects were food provided or deprived. Highest mating rates occurred when sterile or fertile flies provided with food were exposed to 25ºC or 81%–100% relative humidity, while temperatures of 10 and 35ºC and humidity below 60% impaired mating. Overall, mating rate among food‐deprived flies was low in all temperatures and humidity levels tested, but fertile insects were more prone to mate when compared to sterile flies. Survival was negatively influenced by high temperatures, low relative humidity and food deprivation. The information present in this study is useful to be considered for release of sterileD. suzukii.

Sexual inhibition of female Queensland fruit flies mated by males treated with raspberry ketone supplements as immature adults

AbstractRaspberry ketone (RK) dietary supplements accelerate the emergence of sexual behaviour in developing Queensland fruit fly (Q‐fly) males and show promise as a pre‐release supplement for use in sterile insect technique (SIT) programs. However, the value of RK supplements in SIT programs would be greatly reduced if RK‐treated males are ineffective at inducing sexual inhibition in mated females. To test the effectiveness of matings by RK‐treated males, we here investigate the remating propensity of females mated by RK‐treated (1.25% or 5% RK in food) and RK‐untreated (control) males. Tested males received RK supplements mixed in sugar and yeast hydrolysate for 2 days after emerging and then received only sugar. To test for male age‐dependent effects, virgin females were mated to treated and untreated males that were 6, 8, 10, 20 or 30 days old. To test for persistence of sexual inhibition, mated females were tested for remating propensity at 1, 7 or 15 days after their first mating. RK‐treated males did not differ from control males in copula duration, and females mated by RK‐treated males did not differ from those mated by control males in remating propensity, second copula latency or second copula duration. RK‐treated Q‐fly males not only mate at younger ages but also their matings are as effective as those of untreated controls at inducing sexual inhibition in mates.

Parasitoids of Queensland Fruit Fly Bactrocera tryoni in Australia and Prospects for Improved Biological Control.

This review draws together available information on the biology, methods for study, and culturing of hymenopteran parasitoids of the Queensland fruit fly, Bactrocera tryoni, and assesses prospects for improving biological control of this serious pest. Augmentative release of the native and naturalised Australian parasitoids, especially the braconid Diachasmimorpha tryoni, may result in better management of B. tryoni in some parts of Australia. Mass releases are an especially attractive option for areas of inland eastern Australia around the Fruit Fly Exclusion Zone that produces B. tryoni-free fruits for export. Diachasmimorpha tryoni has been successful in other locations such as Hawaii for the biological control of other fruit fly species. Biological control could contribute to local eradication of isolated outbreaks and more general suppression and/or eradication of the B. tryoni population in endemic areas. Combining biological control with the use of sterile insect technique offers scope for synergy because the former is most effective at high pest densities and the latter most economical when the pest becomes scarce. Recommendations are made on methods for culturing and study of four B. tryoni parasitoids present in Australia along with research priorities for optimising augmentative biological control of B. tryoni.

Effect of gamma radiation on the male sterility and other quality parameters of peach fruit fly, Bactrocera zonata (Saunders) (Diptera: Tephritidae)

Bactrocera zonata, a serious pest of fruits in many parts of the world, has recently been recorded in Northern Africa. Even though it has not been introduced to the European continent yet, a strong emphasis is being placed on developing effective measures to suppress this pest and to prevent it from establishing in neighbouring European countries. The sterile insect technique is widely used in integrated programmes against tephritid fruit flies and, in this paper, quality parameters of irradiated B. zonata were evaluated for possible use of sterile insect technique within the management of this pest. Pupae were irradiated (60Co) 48 h before adult emergence (in an air atmosphere) with doses of 10, 30, 50, 70 or 90 Gy. While adult emergence and egg hatch decreased with increasing dose, no significant differences in female fecundity were found among doses. Exposure of pupae to 90 Gy resulted in a total sterility of eggs laid by non-treated females crossed with treated males. Only insignificant difference in the radiation effect on female fecundity was found. Moderate effects on sex ratio and size were recorded, as they decreased gradually by increasing doses. No considerable effect on flying capability was observed, but generally, the percentage of fliers decreased with increasing radiation doses. Fried's competitiveness values of treated males (30 and 70 Gy) suggest that irradiated males compete successfully with non-irradiated ones.

The neogregarine protozoan Farinocystis sp. reduces longevity and fecundity in the West Indian sweet potato weevil, Euscepes postfasciatus (Fairmaire)

The number of West Indian sweet potato weevils, Euscepes postfasciatus, being mass-reared in a facility for use in sterile insect technique (SIT) eradication programs has undergone a drastic reduction. A neogregarine protozoan pathogen Farinocystis sp. (an undescribed species) was detected in vivo in the mass-reared E. postfasciatus. We investigated the effects of this disease on the longevity and fecundity of host weevils and the incubation time of the disease in the host body under mass-rearing conditions. Our results demonstrated that infection by this Farinocystis sp. decreased both longevity and fecundity in E. postfasciatus. In particular, the pathogen severely limited the production of progeny by infected females compared to healthy females. Therefore, we consider this protozoan infection to be the major cause of the decreased E. postfasciatus production in the mass-rearing facility.

Benefit-cost analysis of the use of sterile insect technique to eradicate screwworm fly in the event of an invasion of Australia

The sterile insect technique (SIT) is currently the only available technology capable of eradicating the Old World screwworm fly (SWF) Chrysomya bezziana Villeneuve in the event of it invading Australia and successfully establishing itself. This is based on the success of of SIT in eradicating the New World screwworm fly, Cochliomyia hominivorax Coquerel in North America and Libya, North Africa and the demonstrated adaptation of SIT for the eradication of Chrysomya bezziana by Australian researchers in field trials in Papua New Guinea. The economic evaluation of the eradication of the Old World screwworm fly based on SIT in the event of an invasion of Australia is undertaken with a dynamic spatial bio-economic model using livestock data provided by the Australian Bureau of Statistics 1991 agricultural census. Direct producer losses for the beef cattle, sheep and diary cattle industries are used to establish the economic feasibility of several SIT eradication scenarios involving five factory sizes and ten entry points across Australia. The economic analysis is extended to include the use of economic surplus changes to measure the benefits and costs of eradication incorporating both producer and consumer welfare effects. The results indicate that in the event of an established invasion, the optimal size of a SIT factory appears to be one with a production capacity in the range of 200 to 250 million flies per week. Based on long-term average climate and vegetation and a worst-case scenario of the fly entering Australia through Brisbane at the beginning of the summer, the benefit-cost ratio (BCR) of the base eradication scenario involving a factory size of 250 million flies per week is 7.5. This BCR is based on the use of total direct producer losses to measure the benefits and costs of SWF eradication. The corresponding BCR is about 80% higher (13.9) when both producer and consumer effects are considered.