Ephestia Kuehniella Research Articles

Synergism of a mixed diet of Myzus persicae and egg of Ephestia kuehniella on fitness of the predator Nabis stenoferus

Nabis stenoferus is a zoophytophagous predator that lives in grasslands around agricultural fields. It is a candidate biological control agent for use via augmentation or conservation. To find a suitable food source for mass-rearing and to better understand this predator’s biology, we compared the life history characteristics of N. stenoferus under the three different diets: aphids only (Myzus persicae), moth eggs only (Ephestia kuehniella), or a mixed diet of aphids and moth eggs. Interestingly, when only aphids were supplied, N. stenoferus developed to the adult stage but lacked normal levels of fecundity. There was a significant synergism of the mixed diet on N. stenoferus fitness in both the immature and adult stages, i.e., a 13% reduction in the nymphal developmental period and an 87.3-fold increase in fecundity, compared to aphid-only diet. Furthermore, the intrinsic rate of increase was significantly higher for the mixed diet (0.139) than either aphids only (0.022) or moth eggs only (0.097). These results show that M. persicae alone is not a complete diet for the mass-rearing of N. stenoferus, whereas this aphid can be a supplementary food when combined with E. kuehniella eggs. Implications and applications of these findings for biological control are discussed.

Variation among populations of Trichogramma euproctidis (Hymenoptera: Trichogrammatidae) revealed by life table parameters: perspectives for biological control.

The successful mass-rearing of potential biological control agents is a prerequisite for sustainable pest control. In this study, the performance of 3 Trichogramma euproctidis (Girault) (Hymenoptera: Trichogrammatidae) populations collected from different locations in Khuzestan (Southwest Iran) were evaluated to optimize the egg parasitoid mass-rearing for augmentative biological control of lepidopteran pests. We aimed to investigate the effects of both population origin and host quality on biological traits of ovipositing females (number of parasitized eggs) and of their progeny (development time, survival rate, sex ratio, longevity, and fecundity). The effect of host quality was assessed by allowing the parasitoid to oviposit into 1, 2, 3, or 4-day-old Ephestia kuehniella Zeller (Lepidoptera: Pyralidae) eggs. The 3 T. euproctidis populations developed successfully regardless the age of the host eggs. However, we found significant variation among populations and a strong influence of host quality on the traits investigated. Progeny performance in all populations decreased with increasing host age. The best-performing population (collected in Mollasani) showed the highest parasitization rate, highest survival rate, and progeny sex ratio with the greatest percentage of females. A life table corroborated these findings with superior estimates of the net reproductive rate (R0), intrinsic rate of increase (r), and reduced generation time (T) for the Mollasani population on 1-day-old host eggs. We conclude that ample variation exists among T. euproctidis populations and that rearing the Mollasani population on young rather than old eggs of E. kuehniella would be recommended to implement the biological control programs to target lepidopteran pests in Southwestern Iran.

Male larval experience of cues from adult rivals alters lifetime sperm investment patterns in a sperm heteromorphic moth, Ephestia kuehniella.

Male animals may adjust their resource allocations for reproduction and other fitness functions in response to cues from rivals. For instance, adult males increase their investment in sperm for a higher paternity share when they perceive sperm competition risk in their surroundings. In nature, both juveniles and adults may coexist spatially and temporally. Yet, it is not clear how juvenile males of different ages respond to cues from adult rivals and fine-tune their lifetime investment in sperm production and ejaculation in any insect. Here we used the Mediterranean flour moth, Ephestia kuehniella, which produces both fertile eupyrene and infertile apyrene sperm, to explore this question. We demonstrate that the late, but not early, instar larvae are sensitive to adult male cues. As a response, they produce more sperm before emergence and their resultant adults have shorter mating latency and ejaculate more sperm in the first few matings. When the juvenile stage produces more eupyrenes, the adult stops making these sperm, but regardless of the number of apyrenes produced during the juvenile stage, the adult continues to make them. These findings suggest that the number of spermatogonia for eupyrenes may be limited and that for apyrenes may be flexible. Our results show that the insect does not trade off survival, mating frequency, body size, or testis size for sperm production in response to adult males during the larval stage. Knowledge created in the present study offers insight into the stage-dependent sensitivity of juvenile males to cues from adult rivals and subsequent lifetime resource allocations.

Comparative demography, population projection, functional response and host age preference behavior of the parasitoid Goniozus legneri on two lepidopterous insect hosts

BackgroundThis study was conducted to investigate life table characteristics of the parasitoid species, Goniozus legneri Gordh (Hymenoptera: Bethylidae), a major gregarious larval ecto-parasitoids of the carob moth, Ectomyelois ceratoniae Zeller (Lep.: Pyralidae). Demographic parameters of G. legneri reared on two hosts, the carob moth and the flour moth, Ephestia kuehniella (Zeller) (Lepidoptera: Pyralidae), were studied under laboratory conditions using age-stage, two-sex life table. Host stage preference and the functional response of this parasitoid were also determined.ResultsThe duration of the immature period, adult pre-ovipositional period and total pre-ovipositional period of G. legneri reared on E. kuehniella was significantly longer than that of those reared on E. ceratoniae, while fecundity and ovipositional days of the wasp were greater/longer in females reared on E. ceratoniae. There were also significant differences in intrinsic and finite rates of increase and mean generation time between wasp parasitoid reared on two hosts. Moreover, population projection indicated that the G. legneri population can grow swifter when reared on E. ceratoniae than on E. kuehniella. Based on the experiments conducted to determine the larval stage preferences of G. legneri, for both hosts, larger larvae were more preferred stages compared to smaller ones, thereby fulfilling the optimal oviposition theory. The functional responses of G. legneri to different population densities of E. kuehniella two last instar larvae were determined as type III at 25 °C and 60% RH.ConclusionThe results offer valuable information on some life history attributes of G. legneri. Although G. legneri performed better on E. ceratoniae larvae than on E. kuehniella, as the use of E. ceratoniae larvae as the main host in rearing of G. legneri might be a laborious process and can increase the production costs, E. kuehniella can be used as an alternative host. Further studies are required under greenhouse and field conditions for effective use of this biocontrol agent against the carob moth.

Is a diet of Planococcus citri nymphs and adults suitable for Chrysoperla externa for use in biological control?

Several studies have shown that the survival and reproduction of lacewings varies depending on the type of prey they consumed, especially during the first instar. In this study, we evaluated the effect of a diet consisting of Ephestia kuehniella (EK) and/or Planococcus-citri (PC) eggs offered to first instar Chrysoperla externa on subsequent development and survival. Larvae supplied only with P. citri (PC) nymphs had extended immature development, low survival, adults with lower weight and longevity, low fecundity and egg viability, and lower net reproduction rate (R0). Larvae submitted to the treatment EK+PC responded positively to the diet, showing results similar to those obtained in the control-EK treatment. Therefore, this mealybug supports suitable development and reproduction of C. externa when it is provided to second instar larvae after they fed on E. kuehniella eggs as first instars. As far as we know, this is the first report that demonstrates the effect of natural prey and alternatives on different larval stages of lacewings. This information is valuable in developing protocols for use of C. externaas a pest control agent.

Toxicidade de inseticidas utilizados na cultura do arroz sobre o parasitoide de ovos Trichogramma pretiosum (Hymenoptera: Trichogrammatidae) em condições de campo

ABSTRACT: We evaluated under field conditions the toxicity of insecticides previously identified as harmful in laboratory and semifield bioassays on the parasitoid Trichogramma pretiosum (Hymenoptera: Trichogrammatidae). The experiments were conducted during the 2019/20 and 2020/21 harvests in rice fields. Following the recommendations of the International Organization for Biological and Integrated Control (IOBC), four insecticides were applied in 64 m2 experimental plots. Subsequently, T. pretiosum was released inundatively. To verify parasitism rates, at 1, 2, 4 and 6 days after release (DAR) of the parasitoids, eggs from the host Ephestia kuehniella (Lepidoptera: Pyralidae) were offered. After determining the number of parasitized eggs, the data were grouped into a reduction coefficient (Ex) to provide a single result for the effects of the insecticides on parasitoid. For both the 2019/20 and 2020/21 evaluated crops, it was found that at 2 DAR, the highest parasitism rates occurred. In contrast, in 6 DAR, no parasitism rates were observed. Lambda-cyhalothrin, thiamethoxam, and zeta-cypermethrin were classified as moderately harmful; thiamethoxam + lambda-cyhalothrin was classified as harmful. Following IOBC guidelines, the toxicity of these products under field conditions is lower than that obtained in the laboratory or semi-field for the T. pretiosum. However, these insecticides should be avoided, or used at times that do not coincide with the release or presence of the parasitoid in the field.

Contrasting Phenotypic Variability of Life-History Traits of Two Feral Populations of Macrolophus pygmaeus (Hemiptera: Miridae) under Two Alternative Diets

Tuta absoluta is a major pest attacking tomato crops. This invasive species emerged in Europe (Spain) in 2006, and 3 years later it spread to Portugal. In 2009/2010, it was recorded for the first time in the Azores archipelago. Macrolophus pygmaeus is a predator widely used as biological control agent against the tomato leaf miner. This study contrasted the life-history traits and population growth parameters of two feral populations of M. pygmaeus, one from Portugal mainland and one from the Azores archipelago. The predators were tested on single prey diet, either of Ephestia kuehniella eggs, a factitious prey used for mass rearing of mirids, or T. absoluta eggs. We predicted that populations would express differences in its phenotypic characteristics, with the Azorean population displaying low performance due to likely low genetic diversity, as expected for insular populations. Our results revealed the inexistence of phenotypic differences in several life history traits, such as immature developmental time, female longevity, males’ body weight and sex ratio. Contrary to our predictions, traits with direct impact on fitness, such as lifetime fertility (95.78 ± 14.23 vs. 61.38 ± 13.52 nymphs), explain better performances for the population of the Azores. Azorean M. pygmaeus females were larger, matured earlier and reproduced at a higher rate for longer periods, than mainland females. Therefore, population growth parameters show a positive advantage for the population of the Azores, fed on T. absoluta (time required for doubling the population Azores, Ek: 8.42 ± 0.50, Ta: 5.76 ± 0.31 and mainland, Ek: 10.88 ± 1.94, Ta: 12.07 ± 3.15). Biological performance of M. pygmaeus was similar when fed with T. absoluta or E. kuehniella that could be beneficial both to optimize mass production of the predator and biological control of the pest. Our results are discussed as well in a fundamental perspective, seeking if differences in biological performance can be explained by lower genetic diversity driven by geographic isolation.

A New Mediterranean Flour Moth-Derived Chitosan: Characterization and Co-electrospun Hybrid Fabrication.

In this study, the chitin of adult Mediterranean flour moth (Ephestia kuheniella) (Cht) was extracted and then converted to chitosan by deacetylation process to achieve the chitosan derived from E. kuheniella (Chsfm). The new chitosan-based scaffold was produced using the polyvinyl alcohol (PVA) co-electrospinning technique. The degree of deacetylation was obtained using the distillation-titration and Fourier transform infrared spectroscopy. The surface morphology and crystallinity index of Chsfm were observed using scanning electron microscopy and X-ray diffraction analysis, respectively, and compared with the commercial chitosan (Chsc). Thermogravimetric analysis was used to estimate two chitosans' water content and thermal stability. The average molecular mass analysis was performed using viscometry. Moreover, the minimum inhibitory concentration and DPPH assay were used to study the antimicrobial activity and antioxidant potential of the Chsfm, respectively. Accordingly, Chsfm was smoother with fewer pores and flakes than Chsc, and its crystallinity index was higher than Chsc. The water content and thermal stability were lower and similar for Chsfm compared to Chsc. The average molecular mass of Chsfm was ~ 5.8kDa, making it classified as low molecular weight chitosan. The antimicrobial activity of Chsfm against a representative Gram-negative bacteria; E. coli resulted to be the same as Chsc. However, less effective than Chsc against a representative Gram-positive bacteria is S. aureus. The Chsfm/PVA ratio scaffold was optimized at 30:70 to fabricate a uniform nanofiber scaffold.

Fumigant toxicity of four essential oils against the carob moth Ectomyelois ceratoniae Zeller and the Mediterranean flour moth Ephestia kuehniella

ABSTRACT Eucalyptus leucoxylon, Rosmarinus officinalis, berries, and leaves of Schinus molle essential oils were analysed using GC-MS techniques and assessed for their fumigant toxicity against adults, larvae, and eggs of Ectomyelois ceratoniae and Ephestia kuehniella. Results showed that E. leucoxylon contained Spathulenol, p-Cymene, and Cryptone as major compounds. GC – MS analyses showed that the major compounds of R. officinalis essential oil were 1,8-Cineole, Camphor, and α-pinene. I-Phellandrene, t-Muurolol, and Phellandrene were the major components of the S. molle leaves; while I-Phellandrene, Limonen, and δ-Cadinene were the major components of the S. molle berries. S. molle berries were the most efficient followed by R. officinalis against E. ceratoniae and E. kuehniella. The most effective tested essential oil against E. ceratoniae larvae was S. molle berries. Results on the ovicidal and larvicidal effects of the tested oils demonstrated that R. officinalis was the most effective essential oil against E. kuehniella eggs.

Characterization of silk genes in Ephestia kuehniella and Galleria mellonella revealed duplication of sericin genes and highly divergent sequences encoding fibroin heavy chains.

Silk is a secretory product of numerous arthropods with remarkable mechanical properties. In this work, we present the complete sequences of the putative major silk proteins of E. kuehniella and compare them with those of G. mellonella, which belongs to the same moth family Pyralidae. To identify the silk genes of both species, we combined proteomic analysis of cocoon silk with a homology search in transcriptomes and genomic sequences to complement the information on both species. We analyzed structure of the candidate genes obtained, their expression specificity and their evolutionary relationships. We demonstrate that the silks of E. kuehniella and G. mellonella differ in their hydrophobicity and that the silk of E. kuehniella is highly hygroscopic. In our experiments, we show that the number of genes encoding sericins is higher in G. mellonella than in E. kuehniella. By analyzing the synteny of the chromosomal segment encoding sericin genes in both moth species, we found that the region encoding sericins is duplicated in G. mellonella. Finally, we present the complete primary structures of nine fibH genes and proteins from both families of the suborder Pyraloidea and discuss their specific and conserved features. This study provides a foundation for future research on the evolution of silk proteins and lays the groundwork for future detailed functional studies.

Use of the generalist predator Anystis baccarum in greenhouse IPM: Interactions with other biological control agents, a laboratory study

A generalist predatory mite, Anystis baccarum (L.), was developed as a new biocontrol agent in Canada, and became commercially available in 2022. Because successful biological control programs in greenhouse crops rely on the release of several natural enemies simultaneously to deal with multiple pest species, this study assessed the interaction of A. baccarum with other commonly used biocontrol agents in laboratory trials. Note that only adult stages were used, because the agents tested are predominantly sold and released as adults. Anystis baccarum killed and consumed the generalist phytoseiid mites, Neoseiulus cucumeris (Oudemans) and Amblyseius swirskii Athias-Henriot; however, the mortality of the phytoseiid mites was reduced when an alternative food, Ephestia kuehniella Zeller eggs, was available. There was no intra-guild interaction between A. baccarum and the soil-dwelling predatory mite, Stratiolaelaps scimitus (Womersley). No statistically significant mortality was observed when Orius insidiosus (Say), a generalist hemipteran, or Delphastus catalinae (Horn), a coccinelid beetle used to control whiteflies, were confined with A. baccarum without alternative food for 24 h. The susceptibility of A. baccarum to the entomopathogenic fungus Beauveria bassiana (Balsamo) GHA strain was evaluated by exposing the mites to conidia in a filter paper bioassay. Differences in mite mortality were not significant across all treatments, and only one case of successful sporulation fungal growth was observed from cadavers recovered in the experiments; similarly, differences in the number of eggs produced were not significant across all treatments. Although the laboratory trials sometimes showed severe predation pressure from A. baccarum on other biocontrol agents, they are likely to be functionally compatible in the greenhouse owing to differences in habitat preferences and availability of other prey (pests) or another food source. Results of the current study provide insights that will enable the development of rational biocontrol programs that include A. baccarum.

Lygus rugulipennis on chrysanthemum: Supplemental prey effects and an evaluation of trap plants

AbstractThe European tarnished plant bug, Lygus rugulipennis Poppius, is considered a major pest in chrysanthemum nurseries in The Netherlands. Adults puncture plant's apical meristem, after which the growing point splits and growth is inhibited. Flower buds and flowers can also be severely damaged. Both types of damage result in economic losses for growers. Despite the importance of this pest for chrysanthemum nurseries, there is only very limited information about L. rugulipennis development on chrysanthemum plants, Chrysanthemum × morifolium Ramat., and whether L. rugulipennis can be controlled using trap plants is not known. We investigated whether: (1) L. rugulipennis could develop from egg to adult on the vegetative and flowering stages of chrysanthemum; (2) their performance was enhanced when a supplemental prey source (Ephestia kuehniella Zeller eggs) or another common pest (the green peach aphid, Myzus persicae Sulzer) was present; and (3) there were alternative plant species more attractive than chrysanthemum for use as trap plants for local pest control or monitoring of L. rugulipennis. L. rugulipennis developed on both vegetative and flowering chrysanthemum stages without any additional food source. Nonetheless, when chrysanthemum was supplemented with E. kuehniella eggs, L. rugulipennis achieved the best performance in terms of the number of adults developed and faster developmental time. Interestingly, L. rugulipennis developed faster on chrysanthemum infested with the aphid M. persicae compared to non‐infested plants, however, there was no difference in the number of adults developed. In a trap plant experiment with 16 plant species in the vegetative stage, we found that white mustard, Sinapis alba L., was significantly more attractive than chrysanthemum to both adult and nymph L. rugulipennis. Further research is needed to evaluate the potential of S. alba as a trap plant for monitoring L. rugulipennis and how the presence of prey in the crop influences L. rugulipennis.

Survey of Trichogramma (Hymenoptera: Trichogrammatidae) Natural Populations in Quebec Cranberry Bogs and Identification Using rDNA ITS-2 Sequence Analysis.

The province of Quebec, Canada is the most important organic cranberry growing region worldwide. However, insect pest management methods are limited, and growers face significant yield loss each year, mostly caused by lepidopteran pests. Egg parasitoids of the genus Trichogramma (Hymenoptera: Trichogrammatidae) are effective biocontrol agents of lepidopteran pests in many forests and agricultural systems. Herein, a two-year, large-scale population survey of Trichogramma spp. was performed using Ephestia kuehniella Zeller (Lepidoptera: Pyralidae) as sentinel eggs in Quebec organic cranberry bogs. Collected specimens were identified by sequencing ribosomal DNA of the Internal Transcribed Spacer 2 (ITS-2) region and subjected to resemblance analysis with reference specimens for identification. Our results confirm that at least four Trichogramma species naturally occur in the studied agroecosystem. Those species are T. brassicae Bezdenko, T. minutum Riley, T. ostriniae (Pang et Chen), and T. pretiosum Riley. While some species have already been reported in cranberry bogs, this represents the first mention of T. brassicae and T. ostriniae as well as the first mention of T. minutum in Quebec cranberry bogs. All species collected are native from Eastern Canada except T. ostriniae. These species can be considered as biocontrol agent candidates for cranberry lepidopteran pests, but further efficacy trials are needed to identify the best species for each pest.

Dietary history modifies the innate responses of lady beetles (Coleoptera: Coccinellidae) to odors of their prey-infested host plants

Oenopia conglobata (L.) and Menochilus sexmaculatus F. are two important predators of pistachio psyllid, a key pest of pistachio in Iran, the former indigenous, and the latter recently adventive. Aphis gossypii Glover infests understory plants in pistachio orchards and is used by both species as an alternative prey when psyllids are scarce. We 'conditioned' beetles by rearing them for five generations on these prey and their respective host plants (Pistacia vera L. and Curcurbita pepo L.), or on eggs of Ephestia kuehniella (Zeller) as a control, and measured the preferences of female beetles for plant and plant/prey odors in an olfactometer. When conditioned on Ephestia eggs, both species found P. vera odors attractive, but not C. pepo odors, and although both plants became more attractive when infested with prey, O. conglobata preferred pistachio/psyllid odors over cucumber/aphid odors, whereas M. sexmaculata showed no preference. Whereas conditioning on pistachio/psyllid caused O. conglobata to prefer (unfamiliar) cucumber/aphid odors, its innate preference for the former disappeared when conditioned on cucumber/aphid. In contrast, conditioning on pistachio/psyllid did not alter the innate responses of M. sexmaculata to cucumber/aphid odors, whereas conditioning on pistachio/psyllid caused odors of this complex to be preferred to those of aphid/cucumber. Thus both species exhibited asymmetric, species-specific responses to conditioning treatments that reflected both innate recognition of plant/prey odors, and some plasticity as a function of recent dietary history, which in some cases led beetles to prefer the novel (unconditioned) plant/prey complex. The observed plasticity of innate olfactory responses as a function of conditioning might be advantageous for generalist predators that must frequently switch among different prey types associated with different plants.

Surveys on the Pyraloidea and Geometridae (Lepidoptera) Fauna of Mount Ararat and its surroundings

The present study is carried out between 2017-2019, to determine Pyraloidea and Geometridae fauna of Mount Ararat and its surroundings. The studies are conducted at night with light traps and insect nets during the day. Samples are firstly identified by using their external morphological characteristics and genital structures of taxa are examined when necessary. As a result of the researches, 135 species from Pyraloidea superfamily and 70 species from Geometridae family are determined. Among these taxa, 65 species of Pyraloidea and 41 species of Geometridae are newly discovered in Lepidoptera fauna of Iğdır province. The number of pyraloid species in Iğdır province increased to 217 and the number of geometrid species increased to 118. Information on the new location records and distributions of Ancylodes pallens Ragonot, 1887, Aphyletes nigrisparsella (Ragonot, 1887), Calamotropha paludella (Hübner, [1824]), Cydalima perspectalis (Walker, 1859), Ephestia kuehniella Zeller, 1879, Gymnancyla nomiella (Ragonot, 1887) G. hornigii (Lederer, 1852), Myrlaea mimicralis (Amsel, 1950) and Tephris verruculella (Ragonot, 1887), whose distribution areas are limited in Turkey, are presented.

Population growth traits of the flour moth, Ephestia kuehniella and their relationship with some physical and biochemical properties of various maize hybrids

شب‌پره‌ی‌ مدیترانه‌ای آرد، (Lepidoptera: Pyralidae) Ephestia kuehniella Zeller، آفت مهم محصولات انباری با دامنه وسیع میزبانی است. تخم‌ها و لاروهای این آفت، به‌طور گسترده در برنامه‌های کنترل بیولوژیک به منظور پرورش پارازیتوئیدها و شکارگرها مورد استفاده قرار می‌گیرد. در تحقیق حاضر، تأثیر آرد هیبرید‌های مختلف ذرت شامل KSC 201، KSC 260، KSC 400، KSC 410، SC 705 و SC 706 روی فرآسنجه‌های جدول زندگی شب‌پره‌ی‌ مدیترانه‌ای آرد بررسی شد. هم‌چنین، در این تحقیق برخی از خصوصیات فیزیکی (درصد رطوبت و شاخص سختی) و شیمیایی (محتوی پروتئین و نشاسته) هیبریدها اندازه‌گیری شد تا ارتباط بین این خصوصیات با ویژگی‌های زیستی و جدول زندگی حشره تعیین شود. نتایج نشان داد که هیبرید‌های مختلف ذرت تأثیر معنی‌داری روی ویژگی‌های زیستی و فرآسنجه‌های جدول زندگی آفت داشت. طولانی‌ترین طول مدت نشو و نمای مرحله نابالغ شب‌پره‌ی‌ آرد روی هیبرید SC 706 (54/54 روز) و کوتاه‌ترین دوره‌ی پیش از بلوغ روی هیبرید‌ KSC 410 (52/52 روز) مشاهده شدند. بیشترین میزان زادآوری مربوط به هیبرید‌ KSC 410 (58/210 تخم) و کمترین آن مربوط به هیبریدهای KSC 201 (16/163 تخم) و SC 706 (83/157 تخم) بود. هم‌چنین، کمترین نرخ ذاتی افزایش جمعیت (rm) روی هیبرید SC 706 (065/0 بر روز) و بیشترین میزان آن‌ روی هیبرید KSC 410 (081/0 بر روز) بدست آمد. در این تحقیق، همبستگی مثبت معنی‌داری نیز بین فرآسنجه‌های زادآوری، نرخ خالص تولیدمثل و نرخ ذاتی افزایش جمعیت E. kuehniella با محتوای نشاسته مشاهده شد. نتایج این تحقیق نشان داد که هیبرید KSC 410 به عنوان میزبان‌ مناسب جهت پرورش انبوه E. kuehniella معرفی شد.

Impact of insecticide application used on sugarcane crop on egg predation in the field

Sugarcane, Saccharum officinarum L., has economic importance in Brazil and the world. In addition to its global value as the main source of sugar, energy, and ethanol, it is a raw material for several products. However, phytosanitary problems cause significant losses in the agricultural production of the crop, of which most are only due to the ineffective management of insect pests. We evaluated the impact of the application of insecticides used in sugarcane crops on the predation of eggs of Ephestia kuehniella (Zeller) (Lepidoptera: Pyralidae) under field conditions. For this, cards containing 30 eggs of this species were fixed in the middle third of sugarcane plants and exposed to predation by insects present in areas sprayed with insecticides: thiamethoxam; lambda-cyhalothrin + thiamethoxam; fipronil and Metarhizium anisopliae, in addition to a control (area without spraying). The dose used for insecticides was the minimum recommended for control of insect pests in the crop. The cards remained in the areas for 24 hours after the insecticides spraying, being collected for evaluation after this period. The cards from areas sprayed with thiamethoxam; lambda-cyhalothrin + thiamethoxam and fipronil, the average number of eggs remaining was significantly higher. While in the treatments control and M. anisopliae, there was a significant reduction in the number of preyed eggs, evidencing that the chemical insecticides tested affected the rates of predation in the field, a fact not found with the biological insecticide M. anisopliae.

Optimizing diet thickness and egg density for economic mass rearing of Ephestia kuehniella Zeller, 1879 (Lepidoptera: Pyralidae): A laboratory host for biological control agents

BackgroundMediterranean flour moth [Ephestia kuehniella Zeller, 1879 (Lepidoptera: Pyralidae)] (MFM hereafter) is a significant pest of stored products, particularly flour and causes significant economic damages. However, its eggs are important laboratory host for mass rearing of biological control agents of important agricultural pests. However, diet thickness and eggs’ density to be used in a specific area for economic mass rearing are not fully understood. MethodsThis study optimized the diet thickness and eggs’ density to be used in a specified area for harvesting higher number of MFM eggs with low cost. The MFM was reared under dark environment, i.e., 25 ± 1 °C temperature and 60–70% relative humidity in 32×26×6 cm plastic tubs. The diet consisted of wheat flour and wheat bran in 2:1 ratio by weight, respectively. Three diet thicknesses [i.e., 0.5 cm (thin), 1.5 cm (medium) and 2.5 cm (thick)] and three egg densities [i.e., 25 mg (low), 50 mg (medium) and 75 mg (high)] were tested to determine the most economic and productive combination. ResultsLife history traits, i.e., moths’ production, moths’ ratio and egg production were significantly altered by individual an interactive effect of diet thickness and egg density. The highest number of moths was obtained for medium diet thickness and high egg density. Medium diet thickness with low egg density resulted in the lowest number of moths. The highest number of eggs were produced by thin and medium diets and high egg density combinations, and these combinations proved the most economic for mass production of 100 g eggs. ConclusionThe results of the current study indicated that combination of medium and thin diet thicknesses with high egg density are the most economic for mass production of MFM. Interestingly, the study revealed that terminating moths’ collection at 2nd week after first moth emergence and egg collection at 4 days after the moths are placed in egg laying containers is the most suitable time for the economic mass rearing of MFM. However, egg densities >75 mg need further testing on thin and medium diet thicknesses to explore whether they are more economic than recommended densities in this study.

The Effect of Different Nutrient Combinations on Development Time and Emergence rate of Ephestia kuehniella Zeller (Lepidoptera: Pyralidae)

In this study, the effects of different nutrient combinations on the development time and emergence rate in the cultivation of the host Ephestia kuehniella Zeller (Lepidoptera: Pyralidae), which has an important place in biological control mass production, were investigated. Food experiments were carried out by using 200 g different food combinations in 15 x 20 x 8 cm containers and adding 1.000 Mediterranean flour moth eggs on it. Standard food and ground hazelnut shell were used. 5 different food combinations; A (200 g standard food as a control), B (50 g standard food + 150 g hazelnut shell), C (100 g standard food + 100 g ground hazelnut shell), D (150 g standard food + 50 g ground hazelnut shell) and E (200 gr ground hazelnut shell) were used for the experiments. As a result, no moth emergence was observed in the group E. The development time was 41 days in A, 48.3 days in B, 41.3 days in C, and 41 days in D. The best development time was observed in food combination D compared to food combination A (control). The development time was statistically found significant. The adult emergence rate was 91,86% in A, 18,16% in B, 82,00% in C and, 95,63% in D. As a result, D food combination is recommended in mass production of Ephestia kuehniella, because the development time is short and the adult emergence rate is the highest.

Insecticidal properties of etofenprox for the control of Ephestia kuehniella, Rhyzopertha dominica, Sitophilus oryzae, and Tribolium confusum on stored barley, maize, oats, rice, and wheat.

Etofenprox is a novel pyrethroid insecticide that targets the nervous system of insects by affecting the function of the sodium channel. The current study examines the insecticidal activity of etofenprox against Ephestia kuehniella (Lepidoptera: Pyralidae) larvae, Rhyzopertha dominica (Coleoptera: Bostrychidae) adults, Sitophilus oryzae (Coleoptera: Curculionidae) adults, and Tribolium confusum (Coleoptera: Tenebrionidae) adults and larvae on different grain commodities. For this purpose, etofenprox was applied on barley, maize, oats, rice, and wheat at 0.1, 1, 5, and 10ppm. Mortality levels were recorded after 7, 14, and 21days of exposure. For E. kuehniella larvae, 10ppm applied on whole rice killed 96.1% of the exposed individuals after 21days of exposure.The application of etofenprox on oats at 5ppm caused the death of 98.3% of the exposed R. dominica adults. Complete mortality was observed for R. dominica adults 21days post-exposure to oats and whole rice treated with 10ppm etofenprox. The highest concentration applied on barley caused 95.0% mortality to S. oryzae adults, while the same concentration on maize killed 76.8% of T. confusum adults after 21days of exposure. Larvae of T. confusum exhibited high mortality levels reaching 99.4% after 21days of exposure to barley treated with 10ppm etofenprox. Progeny production of parental R. dominica adults was almost suppressed on all commodities treated with 5ppm etofenprox. The offspring emergence of S. oryzae ranged between 4.4 and 24.6 adults per vial at 10ppm. No T. confusum progeny was produced at 10ppm etofenprox. Our results document that etofenprox is highly effective as grain protectant against several insect species, their developmental stages and their progeny production, but its performance depends on the type of the commodity that it is applied on.