Adult Female Longevity Research Articles

Effect of cinnamon oil encapsulated with silica nanoparticles on some biological and biochemical aspects of the rice moth, Corcyra cephalonica (Staint.) (Lepidoptera: Pyralidae)

Bioassays were carried out to evaluate the effect of sub-lethal concentration (LC50) of mesoporous silica nanoparticles (MSNs), cinnamon oil encapsulated with silica nanoparticles (CESN), cinnamon oil and silica gel on some biological parameters of the 6th instar larvae of Corcyra cephalonica. Pupation percentage, pupal duration, percent of adult emergence and adult longevity decreased in all treatments compared with the control. Pupation percentage recorded 47.5, 45.0 and 37.5% after treatment with silica gel, both of MSNs and CESN and cinnamon oil, respectively, compared to 90% in control. CESN and cinnamon oil prevent all pupae from emergence, while the longevity of adult females and males of larvae treated with MSNs and silica gel decreased as compared to control. Furthermore, the protein profile of the treated larvae was evaluated to explain the mode of action of the tested compounds. The total protein contents were 28.88, 28.65, 28.2 and 30.23 mg/ml after treatment with MSNs, CECN, cinnamon oil and silica gel, respectively, compared to 32.56 mg/ml in the untreated control. Electrophoretic analysis of total proteins evaluated inhibitory action of the used compounds on the protein contents, as the appearance as well as the loss of certain protein fractions.

Sublethal and transgenerational effects of sulfoxaflor on the demography and feeding behaviour of the mirid bug Apolygus lucorum.

Sulfoxaflor, the first commercially available sulfoximine insecticide, has been used for the control of sap-feeding insect pests such as plant bugs and aphids on a variety of crops. However, its sublethal effects on the mirid bug Apolygus lucorum, one of the key insect pests of Bt cotton and fruit trees in China, have not been fully examined. Here, we evaluated the demography and feeding behaviour of A. lucorum exposed to sulfoxaflor. The leaf-dipping bioassay showed that the LC10 and LC30 of sulfoxaflor against 3rd-instar nymphs of this insect were 1.23 and 8.37 mg L-1, respectively. The LC10 significantly extended the nymphal duration and decreased the oviposition period by 5.29 days and female fecundity by 56.99% in the parent generation (F0). The longer duration of egg, 5th-instar nymphs, preadult, and male adult longevity were observed in the F1 generation (F1) at LC10. At the LC30, the duration of egg and 1st-instar nymph, female adult longevity, and oviposition period of the F1 were significantly shorter, while the nymphal duration in the F0 and duration of 5th-instar nymphs, preadult survival rate, and male adult longevity in the F1 significantly increased. The net reproductive rate (R0), intrinsic rate of increase (r), and finite rate of increase (λ) in the F1 were not significantly affected by these two concentrations, whereas the mean generation time (T) was lower at the LC30. Additionally, the probe counts and cells mixture feeding time were markedly lengthened by the LC10 and LC30, respectively, when A. lucorum nymphs exposed to sulfoxaflor fed on Bt cotton plants without insecticides. These results clearly indicate that sulfoxaflor causes sublethal effects on A. lucorum and the transgenerational effects depend on the tested concentrations.

Lethal and sublethal effects of lufenuron on the predator Chrysoperla carnea (Stephens) (Neuroptera: Chrysopidae)

The neuropteran Chrysoperla carnea (Stephens) (Neuroptera: Chrysopidae) is a generalist predator present in Mediterranean agroecosystems. It has a wide range of prey including almost all soft-bodied arthropods; its voracity makes it a suitable agent for inclusion in Integrated Pest Management (IPM) programmes. Use of insecticides that inhibit chitin synthesis has increased and includes the use of benzoylureas (e.g. lufenuron) which negatively affect development of the immature stages of phytophagous insects, both by ingestion and by contact. This study evaluated interactions between lufenuron and the predator C. carnea in the laboratory. Treatment of eggs with lufenuron 24 or 48 h after oviposition had no effect on the proportion successfully hatching, or in the survival of resulting neonate larvae. Topical application of lufenuron to second instar larvae (L2) of C. carnea resulted in high mortality rates; lethal concentration to kill 50% (LC50) was 0.0153 ml/L (0.00860–0.0236 ml/L). Moreover, the development time of third-instar larvae of C. carnea that had consumed prey treated with lufenuron 24 h previously (at a dose of 1 ml/L) was significantly truncated and high percentage mortality was observed when these larvae reached the pupal stage. In choice bioassays a high percentage of C. carnea larvae chose prey treated with lufenuron in preference to untreated prey. Ingestion of lufenuron by C. carnea adults had no effect on female fecundity or adult longevity, but caused a significant reduction in the viability of resulting eggs. In light of these results, the developmental stage of C. carnea should be considered when deciding on the timing of lufenuron applications within IPM strategies.

Agistemus floridanus (Stigmaeidae) as a natural enemy of Panonychus ulmi (Tetranychidae) in vineyards of the Brazilian Southern Region

The aim of this study was to investigate the biology and life table parameters of the predatory mite Agistemus floridanus Gonzalez (Stigmaeidae) feeding on Panonychus ulmi (Koch) (Tetranychidae). The experiment was initiated with 34 eggs of A. floridanus isolated in experimental units and maintained in a controlled environment at 25 ± 1 °C, 12 L:12D, and 80 ± 5% relative humidity. The development time of females was 11.7 ± 1.0 days and the immature phase of males 11.2 ± 1.0 days. Adult longevity of females was 17.1 ± 5.3 days, with mean production of 29.2 ± 17.4 eggs/female. Life table parameters obtained were: net reproduction rate (Ro) 19.8; mean generation time (T) 19.1 days; intrinsic rate of increase (rm) 0.2 female per female per day; finite rate of increase (λ) 1.2 female/female, and population doubling time (DT) 4.4 days. Agistemus floridanus demonstrated survival and reproduction capacity when feeding exclusively on P. ulmi.

Quality control of the parasitoid wasp Trichogramma brassicae (Hymenoptera: Trichogrammatidae) over 45 generations of rearing on Sitotroga cerealella.

Trichogramma brassicae (Bezdenko) is an important biological control agent that has been used widely against many lepidopteran pests. Commonly, colonies of Trichogramma are mass reared on factitious hosts such as Sitotroga cerealella (Olivier) over many generations. In this study, we evaluated the quality and performance of a colony of T. brassicae that had been reared for over 45 generations (G) using two-sex life table parameters and parasitism capacity. We found that female adult longevity was significantly different among sequential generations, ranging from 5.58 ± 2.5 d (at G5) to 3.75 ± 1.42 d (at G45). However, no significant difference was found in male adult longevity among different generations. Although female wasps survived longer until the 15th generation, they allocated more days for egg laying at G5 and G10. The highest values of gross reproductive rate (GRR), net reproductive rate (R0 ), intrinsic rate of increase (r), finite rate of increase (λ) and mean generation time (T) were found in G5 and G10, which also showed significantly higher c0 . No significant difference in the finite parasitism rate (ω) was found among generations up to G15. These results suggest that T. brassicae wasps held under continuous laboratory rearing can be used successfully in biological control programs until the 15th generation without any loss of quality or performance. However, laboratory mass rearing colonies declined in quality after 15 generations and we suggest that they should be rejuvenated regularly by adding field-collected parasitoids periodically.

Effect of Constant and Fluctuating Temperature on the Development, Reproduction, Survival, and Sex Ratio of Phenacoccus solenopsis (Hemiptera: Pseudococcidae).

Effects of temperature on the development, survival, reproduction, longevity and sex ratio of the cotton mealybug, Phenacoccus solenopsis Tinsley, was assessed at five constant temperatures ranging from 20 to 35°C and five fluctuating temperatures ranging from 15 to 40°C under laboratory conditions. Results showed that nymphal development duration, preoviposition period, oviposition period, fecundity, and adult longevity were reduced significantly with increasing temperature until 30°C, but developmental duration of third female nymphal instar and female adult longevity was longer at 35°C than 30°C, and no males could emerge from pupae at the constant temperature 35°C. Fluctuating temperature, in general, significantly accelerated the nymphal developmental duration, prolonged preoviposition period, shortened oviposition period, reduced fecundity, lowered the survival rate of nymphs, and decreased adult longevity of males and females compared to their mean corresponding constant temperature. Overall, it is suggested that one should be prudent when applying the obtained results under constant and fluctuating temperatures under laboratory conditions.

Assessment of Lethal, Sublethal, and Transgenerational Effects of Beauveria Bassiana on the Demography of Aedes Albopictus (Culicidae: Diptera).

Dengue fever is one of the most rapidly spreading arthropod-borne diseases. Diurnal vectorial properties of Aedes albopictus contribute to the dispersion of the dengue viruses. Frequent and injudicious use of synthetic insecticides led to the evolution of resistant phenotypes in Ae. albopictus which necessitates the search for an alternative of current control strategies. Developing a long-lasting and environmentally safe tactic based on knowledge of ecology and population dynamics of Ae. albopictus is critical. Therefore, with a view towards biological control and ecology, the effect of entomopathogenic fungi (EPF) Beauveria bassiana on filial and first filial generations of Ae. albopictus were studied. Investigations showed 87.5% adulticidal activity leading to altered fecundity and adult longevity in a filial generation. The lethal (LC50) and sublethal (LC20) concentrations of B. bassiana were applied to filial generation (F0) to study demographic parameters in the first filial generation (F1). Results showed reduced net reproductive rates (Ro) intrinsic rate of increase (r), and mean generation time (T) compared to uninfected controls. Prolonged larval and pupal duration were observed followed by reduced longevity of male and female adults. Fecundity in the first filial generation was significantly changed with the lethal and sublethal concentrations of B. bassiana. Thus, it is concluded that B. bassiana has the potential to play a vital role in integrated mosquito management strategies.

Effects of Non-Lethal High-Temperature Stress on Bradysia odoriphaga (Diptera: Sciaridae) Larval Development and Offspring.

Throughout China, the dipteran pest Bradysia odoriphaga significantly reduces Chinese chive production; therefore, identifying conditions that influence its growth and development is crucial for developing ecological regulation strategies. In this study, different non-lethal high temperatures and treatment durations were used to stress the third-instar larvae of B. odoriphaga, and the effects of this treatment on their growth and offspring were recorded and analyzed. The results showed that the average larval mortality increased with increased temperature and prolonged exposure times. After stress treatment at 40 °C for 2 h, 100% of larvae died within 5 days, which was not significantly different from the 5-day average larval mortality (90.66%) after stress at 37 °C for 4 h, but significantly higher than the 5-day average larval mortality (72.00%) after stress at 40 °C for 1 h. After 5 days, all still-living larvae could pupate, and there was no significant difference in average pupal period after pupation. However, the eclosion rate of subsequent pupae decreased with increased temperature and prolonged exposure times, and were only 43.00% and 42.73% after larvae were stressed at 37 °C for 4 h and 40 °C for 1 h, respectively. After eclosion into adults, there was no significant difference in the lifespan of unmated female adults, while the lifespan of unmated male adults was significantly reduced to 1.67 d and 2 d after larvae were stressed at 37 °C for 4 h and 40 °C for 1 h, respectively. However, there was no significant difference in male and female adult longevity after mating. There was no significant difference in oviposition or egg hatchability. This indicates that non-lethal high temperature at 37 °C for 4 h can hinder development and allow control of B. odoriphaga. There is great potential for non-lethal high temperature to be applied in the field to control agricultural pests.

Distribution of Galepsus spp. in Southern Africa and Life History of Galepsus lenticularis (Mantodea: Tarachodidae).

Galepsus Stäl is a genus within the Mantodea and has hardly been studied in Africa. The distribution of the Galepsus genus in Southern Africa was established, based on insect collection records, and the biology of Galepsus (Lygdamia) lenticularis Saussure, was studied. In Southern Africa, 11 species of Galepsus were recorded. The first record of Galepsus (Onychogalepsus) centralis Beier, in South Africa was recorded during this study. The mean number of eggs per ootheca was 49.8 (±21.1) and unfertilized oothecae were significantly shorter and contained fewer eggs than hatched and unhatched oothecae, suggesting that females might invest fewer resources into production of oothecae that will not produce prodigy. No parthenogenesis was observed during this study. Although the mean duration of the male and female nymphal stages were similar, longevity of adult females (91.2 ± 35.0 days) was three times longer than that of males (26.3 ± 15.4 days). This phenomenon as well as the long period (20 ± 14.1 days) between oviposition of different oothecae, and duration of the incubation period (20.25 ± 6.3 days) suggests a survival strategy to reduce competition between siblings. Total longevity of males (166.9 ± 38.8) and females (252.9 ± 54.2) differed significantly. This study provides information on the distribution of Galepsus spp. in Southern Africa and describes the biology of G. lenticularis under captive breeding conditions, and contributes to the understanding of various biological aspects of G. lenticularis which has never been studied before.

The effect of thermal waves on the biology and immune function of the cotton leafworm, Spodoptera littoralis (Lepidoptera: Noctuidae)

The climatic changes have been more frequent, thus modern studies focus on examining the biological responses of life forms to thermal waves either cold or hot. Temperature is one of the most important environmental factors affecting the performance and life history of insects. Therefore, this study aimed to investigate the changes occurring in the pest, Spodoptera littoralis after exposure to 5-day thermal waves defined as cold (15°C) and hot (35°C), whereas 25°C was used as (normal) control temperature. Newly emerged adults were used to estimate fecundity, survival and egg hatchability. Third instar larvae were used to assess the effects of thermal waves on the immune function (protein content and phenoloxidase activity) and the susceptibility to infection with potent entomopathogenic fungi, Beauveria bassiana and Metarhizium anisopliae. The results showed that S. littoralis females experienced cold or hot wave showed less fecundity and egg hatchability as compared to those in the control temperature. Moreover, hot-wave induced shorter longevity, while cold-wave induced longer adult female longevity. The larvae exposed to thermal waves showed contrasting haemolymph protein contents, but lower phenoloxidase activity than those in the control temperature. Exposure of the fungus-infected larvae to thermal waves was able to affect the percentage mortality and time to death. In more details, particularly, exposure to the cold wave induced longer mortality time and lower percentage mortality than those in the control temperature. These results may enhance our understanding of the effect of climatic changes on the biology of S. littoralis and its control programs.

<p class="Body"><strong>Comparison of different pollen grains and a factitious prey as food sources for <em>Amblyseius swirskii</em> (Acari: Phytoseiidae)</strong></p>

Pollen used as an alternative or supplementary food source for a predatory mite not only provides important nutrients but also allows the predator to establish a population before prey becomes available. In this study, we compared the pollen of apricot, pear, hollyhock, opium poppy, and date palm, and a factitious prey, UV-irradiated eggs of Ephestia kuehniella, as food sources for Amblyseius swirskii. Different food items affected all development stages differently, except for hollyhock pollen, where eggs failed to develop to maturity. Food type affected the reproductive ability of females, which did not reproduce when fed on opium poppy during immature stages. Most eggs per female were produced when feeding on the factitious prey, and second most with apricot pollen. Feeding on factitious prey compared with pollen, resulted in greater longevity of both female and male adults. Feeding on pear pollen or factitious prey caused, respectively, the lowest and highest population growth rates (r and λ). Both net (R0) and gross (GRR) reproductive rates were highest when the factitious prey was the food source. Among the pollen diets, apricot was the most beneficial food item. Because of their effects on rates of population increase, either apricot pollen or the factitious prey could be further utilized as cost-effective alternative food diets for both experimental and commercial mass rearing of A. swirskii.

Nitrogen fertilization of rice plants improves ecological fitness of an entomophagous predator but dampens its impact on prey, the rice brown planthopper, Nilaparvata lugens

Nitrogen fertilizers are widely used to maximize crop productivity but are also known to benefit pest insects. Here we show that nitrogen not only increased the egg size of the key pest, brown planthopper (BPH), Nilaparvata lugens Stal, but also benefitted the predatory mirid bug, Cyrtorhinus lividipennis Reuter (Hemiptera: Miridae). Predator nymph survival and development rate, female adult weight, longevity and fecundity were all enhanced. Importantly, however, high nitrogen levels also extended the predator handling time (Th), reducing the number of prey eggs attacked per predator and signalling a weakening of top-down control. We conclude that nitrogen fertilizer can exacerbate pest impact by natural enemy-mediated effects in addition to previously reported direct effects on herbivores. Our results highlighted the need to moderate the use of nitrogen fertilizers to maintain effective biological control of these rice pests to reduce dependence on insecticides, another potentially hazardous input.

Bottom‐up effect of host plants on life‐history characteristics of Aphidoletes aphidimyza feeding on Aphis gossypii

AbstractThe predatory midge Aphidoletes aphidimyza (Rondani) (Diptera: Cecidomyiidae) is widely used for the control of Aphis spp. in many agricultural systems. We aimed to determine the most suitable host plant for rearing the predatory midges on the prey Aphis gossypii Glover (Hemiptera: Aphididae). Six host plants were selected: cucumber (Cucumis sativus L. cv. Beith Alpha), tomato (Solanum lycopersicum L. cv. Falat111), eggplant (Solanum melongena L. cv. Yummy), pepper (Capsicum annuum L. cv. Bertene) (all Solanaceae), okra [Abelmoschus esculentus (L.) Moensch cv. Clemson Spineless] (Malvaceae), and squash (Cucurbita pepo L. cv. Hybrid rajai) (Cucurbitaceae). Some physical traits (length and density of trichomes) and chemical attributes (nitrogen content) of prey host plants were investigated. The results showed that prey host plants differed significantly in their effect on fitness of the predator. The shortest immature development time (18.07 ± 0.257 days), the longest female adult longevity (7.5 ± 0.18 days), and the highest fecundity (89 eggs/female) of A. aphidimyza were found with squash as prey food. The highest intrinsic rate of increase (0.171 ± 0.009 day−1) and also the shortest mean generation time (22.4 ± 0.32 days) were also obtained when A. aphidimyza fed on A. gossypii reared on squash. Canonical correlation analysis (CCA) approved the correlation between life‐history traits of A. aphidimyza and characteristics of prey host plants. The suitability of squash for rearing A. aphidimyza can be attributed to the higher nitrogen content, longer trichomes, and relatively high density of trichomes, which provided a better environment for A. gossypii and indirectly favored A. aphidimyza. This study showed that squash is the most suitable host plant for rearing A. aphidimyza feeding on A. gossypii.

Effects of hexaflumuron, lufenuron and chlorfluazuron on certain biological and physiological parameters of Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae)

Abstract Helicoverpa armigera (Hubner) (Lepidoptera: Noctuidae) is one of the most economically devastating pests of agricultural crops around the world. In this study, the effects of hexaflumuron, lufenuron and chlorfluazuron were evaluated on some biological and physiological parameters of H. armigera larvae. Effects of the insecticides were assessed by adding different concentrations into the larval artificial diet. Dose-response bioassay showed LC50 values of 6.16, 61.31 and 31.75 mg ai/l for hexaflumuron, lufenuron and chlorfluazuron, respectively. Subsequently, sublethal effects of hexaflumuron, lufenuron and chlorfluazuron were assessed using LC10 concentration to find their possible effects on the biological and physiological parameters of H. armigera larvae. The results showed significant changes in biological parameters, where the mean larval and pupal weights significantly decreased following treatment, while their developmental time significantly increased compared to the control. Meanwhile, the longevity of adult males and females, number of laid eggs per female, and rate of egg hatch were significantly reduced due to the insecticide treatments. The activities of alanine aminotransferase, aspartate aminotransferase, γ-glutamyl transferase, acid- and alkaline phosphatases, lactate dehydrogenase, glutathione S-transferase were increased following the treatments. Sublethal exposure of the insecticides on larvae led to lower amounts of glycogen, triglyceride and protein compared to the control.

Biology and Reproductive Behaviour of Apanteles taragamae Viereck (Hymenoptera: Braconidae), a Larval Parasitoid of Diaphania indica Saunders (Lepidoptera: Crambidae)

Apanteles taragamae (Hymenoptera: Braconidae) is a larval parasitoid of Diaphania indica (Saunders) (Lepidoptera: Crambidae), a minor pest of Cucurbitaceae crop. The aim of this study was to determine the behavior and biology of A. taragamae. The study was conducted under laboratory conditions by exposing 930 larvae of D. indica to be parasitized by 11 adult female parasitoid of A. taragamae (1 day old), which have been mated 24 hours prior to expose. Each female was exposed to 15 larvae/day until they died. The parameters used to measure the biology of A. taragamae were fecundity, longevity, and parasitism. Results showed that the longevity of adult females was 5.64 days, the parasitism was 96%, the number of egg laid was 76.40/day, the total number of eggs laid was 611.18, and potential fecundity was 752.73 egg.

Polyandry and trade-off between fecundity and longevity in female Dichelops furcatus (Hemiptera: Pentatomidae).

A trade-off is a relationship between two life history characteristics principally reproduction and adult longevity that are fundamental in predicting the optimal life history in any given environment. Mating is indispensable for sexual reproduction, but also can impose risks to females. Nevertheless, in the majority of insects, females allow multiple mating. Dichelops furcatus (Hemiptera: Pentatomidae) is a pest of wheat and corn in Argentina and southern Brazil, but little is known about its reproduction (i.e., the characteristics of the process that results in offspring). We analyzed reproductive attributes of D. furcatus, and the effect of single mating vs. multiple matings, evaluating the trade-off between fecundity and adult female longevity. We found that mating is not required for D. furcatus to oviposit, and multiple copulations were costly in terms of reduced longevity. Although multicopulated females lived a shorter period, only the pre- and post-reproductive periods were shortened. Fecundity was not affected but fertility was incremented in multicopulated females. Females copulated only once oviposited most of the eggs in the first half of the reproductive period, while eggs oviposited in the second half were all inviable (did not hatch). Studying demographic attributes of phytophagous insects provides relevant information to better understand the population dynamics of pests.

The maternal effects of heat shock on biological parameters and ovaries of Frankliniella occidentalis (Thysanoptera: Thripidae)

Maternal effects of heat shock are reported for some species of insects, but little is known about such effects in the western flower thrips (WFT) Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae). WFT is a pest of vegetables in greenhouses worldwide. It is susceptible to high temperatures in its natural environment and is controlled using heat treatment in China. WFT population growth is suppressed by a brief exposure to a high temperature of 40°C or 45°C in the laboratory. To explore the mechanism by which high temperatures suppress the growth of WFT populations, as well as the effects of multiple heat treatments on WFT, we recorded the duration of development and survival of immature WFT, and the sex ratio (female/male) and fecundity of F1, F2, F3 and F4 adult females that developed after a single heat shock, and those of F2 offspring after a double heat shock. We also recorded the longevity and ovarian structure of adult females of the treated generation (P) and their F1, F2 and F3 offspring after a single heat shock. In addition, we determined whether the effects of a heat shock on second instar nymphs and adults differed. The results indicate that exposure of the parental generation to 41°C or 45°C for 2 h significantly prolonged the duration of development, reduced survival of immature WFT and altered the sex ratio (female/male), longevity and fertility of their adult female offspring. The effects of a heat shock of 41°C persisted for two generations, whilst the effect of heat shock of 45°C persisted for three generations. In addition, double heat shocks had more pronounced effects than a single heat shock. Heat shock administered to second instar nymphs resulted in a decrease in the number of ovarioles, whilst a heat shock administered to adults resulted in ovariole deformity. The maternal effects of heat shock in terms of the biological parameters of WFT, structure and number of ovarioles, are critical in determining the suppression of the growth at high temperatures of WFT populations.

Effect of Two Egyptian Cotton Varieties on Development and Life Table of the Two-Spotted Spider Mite, Tetranychus urticae Koch (Acari: Tetranychidae) in Relation to Leaf Chemical Contents

The development and life table of the two-spotted spider mite, Tetranychus urticae Koch (Acari: Tetranychidae) were studied when reared on two Egyptian cotton varieties: Giza 86 and Giza 90 at laboratory conditions of 27±2°C and 60±5% R.H. Results cleared that the development of T. urticae female was significantly affected by cotton variety. Immatures developmental time was shorter on Giza 90 (3.82 days) than Giza 86 (9.86 days). The adult female longevity averaged 12.29 and 16.65 days on Giza 90 and Giza 86, respectively. In addition, the values of Net reproductive rate (Ro), Intrinsic rate of natural increase (rm) and Finite rate of increase per day (λ) of T. urticae were (65.04, 0.407 and 1.502 days) and (31.95, 0.184 and 1.202 days) on Giza 90 and Giza 86, respectively. The female fecundity recorded 98.63 and 71.00 eggs / female on Giza 90 and Giza 86, respectively. The mean generation time (T) and generation doubling time (DT) values were the lowest on Giza 90 (10.27, 1.702 days) than Giza 86 (18.82, 3.766 days), respectively. A positive significant correlation was recorded between development, fecundity of T. urticae female and availability leaf nitrogen content.

Disruptive Effectiveness of Methoprene (A Juvenile Hormone Analogue) on Adult Performance and Natality of the Grey Flesh Fly Parasarcophaga argyrostoma (Diptera: Sarcophagidae)

The grey flesh fly Parasarcophaga argyrostoma plays a role in human cutaneous wounds and eye myiasis as well as it acts as a parasitoid of various animals. The present study aimed to investigate the efficacy of methoprene on the adult performance and natality of this fly. Five dose levels (10.0, 5.0, 1.0, 0.1 and 0.01 μg/larva) of methoprene was topically applied onto the early last instar larvae and prepupae. The adult emergence of flies was completely blocked at the highest dose, regardless of the time of treatment. At other dose levels, the adult eclosion was partially blocked. Survival of the adult flies was adversely affected by the toxic potency of methoprene. Only at doses of 5.0 and 1.0 μg/larva, some morphologically deformed flies were observed. The total longevity of adult females was remarkably shortened in a dose-dependent course. Topical application of methoprene onto either last instar larvae or prepupae resulted in a considerably prolonged pre-larviposition period, but significantly shortened larviposition period. Topical treatment of either last instar larvae or prepupae with methoprene led to dramatic reduction in natality, in a dose-dependent course.

Fumigant toxicity and sublethal effects of Teucrium polium essential oil on Aphis fabae scopoli A

ObjectiveBlack bean aphid (Aphis fabae) is one of the most important greenhouse and crop pests with a wide range of hosts, which causes damages through feeding on vegetable sap and transmitting viral diseases. Currently, chemical methods are mainly used to control this pest. Considering the adverse effects of pesticides, it is essential to apply less chemical pesticide in pest control programs. The lethal and sublethal effects of the essential oil (EO) of Teucrium polium leaves on one-day-old adults of black bean aphid were investigated under laboratory conditions. MethodThe bioassay was evaluated at the concentrations of 0.88−12 µL/L air, for 24 h after treatment. Reproductive life table parameters of new emerged aphid surveyed at sub-lethal concentrations (LC20 and LC40) of EO and the biological reproductive table was calculated by Jackknife method. ResultsThe mortality rate increased significantly with the increasing of EO concentration. The estimated LC50 value was 4.5 µL/L air. Laboratory exposure to sublethal concentrations of EO caused significant decrease in adult female longevity and fertility of surviving aphids and as a result caused significant reduction in the intrinsic rate of natural increase (rm value). ConclusionThe results of this study revealed that EO of T. polium could be used as a potential control agent for the aphid.