Instar Stage Research Articles

Twist is required for muscle development of the adult legs in Henosepilachna vigintioctopunctata.

Although muscle development has been widely studied in Drosophila melanogaster, it was a great challenge to apply to developmental processes of other insect muscles. This study was focused on the functional characterization of a basic helix-loop-helix transcription factor gene twist in an herbivorous ladybird Henosepilachna vigintioctopunctata. Its transcript (Hvtwist) levels were detected in all developmental stages. RNA interference (RNAi)-aidedknockdown of Hvtwist at the penultimate larval instar stage impaired pupation, and caused a deformed adult in the legs. The tarsi were malformed and did not support the bodies in an upright position. The climbing ability was impaired. Moreover, around 50% of the impaired adults had a malformed elytrum. In addition, they consumed less foliage and did not lay eggs. A hematoxylin-eosin staining of the leg demonstrated that the tibial extensor (TE)and the tibial flexor (TF)muscles were originated from the femurs while levator and depressor muscles of the tarsus (TLand TD) were located in the tibia in the control adults, in which tarsal segments were devoid of muscles. RNAi treatment specific to Hvtwist expression markedly impaired TE and TF muscles in the femurs, and prevented the development of TL and TD muscles in the tibia. Therefore, our findings demonstrate Twist plays a vital role in the myogenesis in H. vigintioctopunctata adult legs.

Microplastic pollution differentially affects development of disease-vectoring Aedes and Culex mosquitoes

Plastic in the form of microplastic particles (MPs) is now recognized as a major pollutant of unknown consequences in aquatic habitats. Mosquitoes, with aquatic eggs, larvae, and pupae, are likely to encounter microplastic, particularly those species that are abundant in close proximity to human development, including those that vector human and animal disease. We examined the effects of polyethylene MPs, the most common microplastic documented in environmental samples, on the development and survival of the mosquitoes Aedes albopictus and Culex quinquefasciatus. In laboratory egg-laying and larval development container environments similar to those used by both species in the field, a mix of 1–53 µm MPs at concentrations of 60, 600, and 6000 MP ml−1 increased early instar larval mortality in both species relative to control treatments. A significant difference was found in the response of each species to microplastic at the lowest microplastic concentration tested, with Cx. quinquefasciatus survival equivalent to that in control conditions but with Ae. albopictus larvae mortality elevated to 37% within 48 h. These results differ from those of previous studies in which larvae were only exposed to MPs during the last aquatic instar stage and from which it was concluded that microplastic was ontogenically transferred without negatively affecting development. Increasing plastic pollutant concentrations could therefore act as selective pressures on aquatic larvae and ultimately influence outcomes of ecological interactions among mosquito vector populations.

Description of life cycle and immature stages of Yphthimoides celmis (Godart, [1824]) (Lepidoptera: Nymphalidae: Satyrinae): a contribution to the taxonomic status of the genus.

This article describes the immature stages of the satyrid butterfly Yphthimoides celmis (Godart) for the first time. Morphology, head and body chaetotaxy, and coloration patterns are compared with those of other Yphthimoides species. Larvae behavioral aspects and oviposition behavior are also documented here. Overwintering larvae are observed for the first time for this genus. The larval stage has four or five instars in non-overwintering while six in overwintering larvae. The average duration of the life cycle is around 82 days for non-overwintering, while it is 227 days for overwintering larvae under laboratory conditions. The increase in instar stages and the development time duration of immature stages in overwintering larvae may be due to climatic conditions in the study area and also a strategy to survive the cold season. Eggs have irregular pentagonal and hexagonal cells. First instar larvae have a dark head capsule and a pattern of reddish stripes along their body, with clubbed body setae. Pupae are short and smooth with a non-uniform brown color, presenting a lighter clypeus and a darker ventral portion in the cremaster. We consider that the morphological information of immature stages can improve further phylogenetic studies.

Reduced expression of the P-glycoprotein gene HaABCB1 is linked to resistance to Bacillus thuringiensis Cry1Ac toxin but not Cry2Ab toxin in Helicoverpa armigera

Rapid evolution of pest resistance to Bt insecticidal proteins presents a serious threat to the sustainable use of Bt crops. The cotton bollworm has been extensively exposed to Bt cotton worldwide and has evolved resistance in laboratory and field. Previous studies have highlighted the significant roles played by the ABC transporter proteins in Bt resistance. In this study, the ORF of HaABCB1 was cloned and analyzed. The expression of HaABCB1 was detected in all developmental stages and tissues, with the highest expression in third instar larvae stage and hindgut tissue. Compared with susceptible strain, a remarkable decrease of HaABCB1 expression in Cry1Ac resistant strain while no significant change in Cry2Ab resistant strain were found. The HaABCB1 expression reduced after susceptible larvae induced by Cry1Ac, but no obvious expression changes after Cry2Ab exposure. RNAi-mediated down-regulation of HaABCB1 could lead to a significant reduction in larval susceptibility to Cry1Ac, but not to Cry2Ab, in susceptible strain. Genetic linkage analysis confirmed that decreased expression of the HaABCB1 mediates resistance to Cry1Ac, but not Cry2Ab resistance. This knowledge contributes to better understanding of the complex molecular mechanisms underlying Bt resistance and provide theoretical foundation for the development of new strategies for pest resistance management.

Performance of Six Genetically Diverse Phylloxera Strains on 5C Teleki (V. berlandieri × V. riparia) Rootstock

Background and Aims. Grapevine phylloxera, Daktulosphaira vitifoliae (Fitch), feeds on roots and leaves of Vitis spp. Susceptibility to phylloxera differs among rootstocks, such that Vitis spp. grafted onto resistant rootstocks can safeguard vineyards from phylloxera-induced damage in the long term. Diverse phylloxera genetic strains, however, vary in their ability to survive on different rootstocks. The 5C Teleki rootstock (V. berlandieri × V. riparia) is widely planted worldwide, but its resistance to phylloxera has not been characterised against the genetically diverse phylloxera strains present in Australia. Methods and Results. 5C Teleki roots and Vitis vinifera L. (positive control), either excised in Petri dishes or planted as whole plants in pots, were inoculated with eggs of six phylloxera strains (G1, G4, G19, G20, G30, and G38). On excised roots, G19, G20, G30, and G38 phylloxera survived to reproductive adults. The G1 and G4 phylloxera did not survive past the first instar stage. In potted vines, G4, G19, G20, G30, and G38 phylloxera strains induced nodosities on roots, but adults were only found on roots inoculated with G19 and G20 phylloxera strains. Conclusions. Results showed that 5C Teleki is resistant to the G1 phylloxera and susceptible to G19 strains. Performance of G4, G20, G30, and G38 differs depending on the assay used. 5C Teleki is likely tolerant of these strains. Significance of the study: the 5C Teleki rootstock is resistant to the G1 phylloxera strain but likely tolerant of others present in Australia. This implies that the rootstock can still host a population of phylloxera, and strict farm-gate hygiene should be employed to stop spread among vineyards and regions.

Azadirachtin Inhibits Nuclear Receptor HR3 in the Prothoracic Gland to Block Larval Ecdysis in the Fall Armyworm, Spodoptera frugiperda.

Azadirachtin has been used to control agricultural pests for a long time; however, the molecular mechanism of azadirachtin on lepidopterans is still not clear. In this study, the fourth instar larvae of fall armyworm were fed with azadirachtin, and then the ecdysis was blocked in the fourth instar larval stage (L4). The prothoracic glands (PGs) of the treated larvae were dissected for RNA sequencing to determine the effect of azadirachtin on ecdysis inhibition. Interestingly, one of the PG-enriched genes, the nuclear hormone receptor 3 (HR3), was decreased after azadirachtin treatment, which plays a critical role in the 20-hydroxyecdysone action during ecdysis. To deepen the understanding of azadirachtin on ecdysis, the HR3 was knocked out by using the CRISPR/Cas9 system, while the HR3 mutants displayed embryonic lethal phenotype; thus, the stage-specific function of HR3 during larval molting was not enabled to unfold. Hence, the siRNA was injected into the 24 h L4 larvae to knock down HR3. After 96 h, the injected larvae were blocked in the old cuticle during ecdysis which is consistent with the azadirachtin-treated larvae. Taken together, we envisioned that the inhibition of ecdysis in the fall armyworm after the azadirachtin treatment is due to an interference with the expression of HR3 in PG, resulting in larval mortality. The results in this study specified the understanding of azadirachtin on insect ecdysis and the function of HR3 in lepidopteran in vivo.

Laboratory scale evaluation of the feasibility of locally found bladderworts as biological agents to control dengue vector, Aedes aegypti in Sri Lanka

BackgroundThe carnivorous genus Utricularia also includes aquatic species that have the potential to trap a wide range of prey, leading its death due to anoxia. However, the effectiveness of such an approach with carnivorous plants for vector control has not been evaluated in Sri Lanka.MethodsEarly instar (i & ii) and late instar (iii & iv) larvae of Aedes aegypti were exposed to locally found bladderwort (U. aurea Lour and Utricularia sp.). The experimental design was set with 10 larvae (both early and late instars separately) in 250 mL of water with bladderworts containing approximately 100 bladders in plant segments of both species, separately. Each treatment and control were repeated 50 times. The survival status of larvae was recorded daily until death or adult emergence. The larvae found whole or partially inside the bladders were attributed to direct predation. The Cox-regression model and Mantel-Cox log rank test were carried out to assess the survival probabilities of larvae in the presence of two bladderworts separately.ResultsThe highest predation was observed when using early instar larvae in both U. aurea (97.8%) and Utricularia sp. (83.8%). The mortality caused due to predation by U. aurea was observed to be significantly higher according to the Mantel-Cox log-rank test (HR = 60.71, CI; 5.69–999.25, P = 0.004). The mortality rates of late instar stages of Ae. aegypti were observed to be lower in both U. aurea (82.6%) and Utricularia sp. (74.8%). Overall, the highest predation efficacy was detected from U. aurea (HR = 45.02; CI: 5.96–850.51, P = 0.017) even in late instar stages. The results suggested the cumulative predation in both plants on Ae. aegypti larvae was > 72%.ConclusionsUtricularia aurea is a competent predator of Ae. aegypti larvae. Further, it is recommended to evaluate the feasibility of this plant to be used in the field as a control intervention in integrated vector management programmes.

Colorimetric Synchronization of Drosophila Larvae.

The rapid succession of events during development poses an inherent challenge to achieve precise synchronization required for rigorous, quantitative phenotypic and genotypic analyses in multicellular model organisms. Drosophila melanogaster is an indispensable model for studying the development and function of higher order organisms due to extensive genome homology, tractability, and its relatively short lifespan. Presently, nine Nobel prizes serve as a testament to the utility of this elegant model system. Ongoing advancements in genetic and molecular tools allow for the underlying mechanisms of human disease to be investigated in Drosophila. However, the absence of a method to precisely age-match tissues during larval development prevents further capitalization of this powerful model organism. Drosophila spends nearly half of its life cycle progressing through three morphologically distinct larval instar stages, during which the imaginal discs, precursors of mature adult external structures (e.g., eyes, legs, wings), grow and develop distinct cell fates. Other tissues, such as the central nervous system, undergo massive morphological changes during larval development. While these three larval stages and subsequent pupal stages have historically been identified based on the number of hours post egg-laying under standard laboratory conditions, a reproducible, efficient, and inexpensive method is required to accurately age-match larvae within the third instar. The third instar stage is of particular interest, as this developmental stage spans a 48-hr window during which larval tissues switch from proliferative to differentiation programs. Moreover, some genetic manipulations can lead to developmental delays, further compounding the need for precise age-matching between control and experimental samples. This article provides a protocol optimized for synchronous staging of Drosophila third instar larvae by colorimetric characterization and is useful for age-matching a variety of tissues for numerous downstream applications. We also provide a brief discussion of the technical challenges associated with successful application of this protocol. © 2023 Wiley Periodicals LLC. Basic Protocol: Synchronization of third instar Drosophila larvae.

Effect of amino acid fortified mulberry leaves on economic and biological traits of Bombyx mori L.

The demand for silk has been increasing day by day but the average silk production is not enough to meet its demand. In this study, we investigated the effect of amino acid supplemented mulberry feed on the biological and commercial traits of Bombyx mori L. (Lepidoptera; Bombycidae). The silkworm larvae at 5th instar stage were taken and fed with fresh and healthy mulberry leaves coated with Alanine, Glycine and Serine in fourteen different combinations. Results of the current study revealed that the average weight of silkworm larvae and the % ratio of silk gland to body weight on day 7 was significantly (P˂0.05) higher in the group fed with amino acid fortified leaves as compared to the control. The commercial traits of larvae fed with amino acid fortified leaves also improved significantly. The larvae fed with Alanine (1 %) treated mulberry leaves showed the maximum cocoon weight, cocoon length, cocoon width, cocoon shell ratio and fibroin content as compared to the control group. It is evident from the results that the amino acid (particularly alanine) coated mulberry leaves have a positive effect on the commercial and biological traits of Bombyx mori (L.).

Quantitative Estimation of Amylase Activity in Selected Larval Mutants of Silkworm Bombyx mori L. Reared on Two Mulberry Varieties

Four larval mutants namely Knobbed, Zebra, pere and Ursa of the silkworm, Bombyx mori L. were selected for the present investigation. The digestive juice and haemolymph were collected from fifth instar larvae (day 1 to day 6) and the samples were subjected to spectrophotometric analysis for estimation of amylase activity. The recorded O.D. values (at 525 nm) were converted into maltose released (µmoles ml-1). The results of the present study clearly indicate that the amylase activity gets enhanced with the increase in number of feedings along with the advancement of age during 5th instar larval stage (day 1 to 6). Based on the results obtained, Zebra performed better followed by Knobbed than the other two larval mutants under study. The larvae fed with V1 variety performed better than those batches fed with S36 variety of mulberry in both the samples. Of the two samples, amylase activity recorded higher in digestive juice than haemolymph in all the four larval mutants under study.

Pest management of postharvest potatoes: lethal, sublethal and transgenerational effects of the ectoparasitic mite Pyemotes zhonghuajia on the potato worm Phthorimaea operculella.

Potato, Solanum tuberosum, is one of the most important food crops in the world, playing a significant role in global food security. However, many potato industries and farms may suffer losses of tuber yield and quality in storage due to lepidopteran pests. Here, we evaluated the effectiveness of an ectoparasitic idiobiont mite Pyemotes zhonghuajia in the biological control of the potato tuber moth (PTM) Phthorimaea operculella by determining the lethal, sublethal (nonconsumptive) and transgenerational effects of P. zhonghuajia of various population densities and exposure durations on PTM survival, development and reproduction. Pyemotes zhonghuajia females were capable of killing all instar stages of PTM, while resistance to mite parasitism increased with the development of PTM life stage. The mortality of mature larvae (i.e., fourth instar) and pupae increased with increasing mite density and exposure duration. P. zhonghuajia imposed significant negative sublethal impacts on PTM pupation rate, female fecundity and adult longevity but not on immature development. The sublethal stress was transgenerational, resulting in lower reproduction in the offspring generation. P. zhonghuajia induces lethal, sublethal and transgenerational effects and significantly decreases PTM survival and reproductive out, demonstrating its high efficiency in the biological control of PTM. Our study provides insight into the mechanisms underlying the nonconsumptive effects of parasitism in an ectoparasite-host system and delivers critical information for the design and implementation of augmentative releases of P. zhonghuajia in the biological control of PTM in potato storage. © 2023 Society of Chemical Industry.

The Wnt pathway regulates wing morph determination in Acyrthosiphon pisum

Wing dimorphism occurs in insects as a survival strategy to adapt to environmental changes. In response to environmental cues, mother aphids transmit signals to their offspring, and the offspring either emerge as winged adults or develop as wingless adults with degeneration of the wing primordia in the early instar stage. However, how the wing morph is determined in the early instar stage is still unclear. Here, we established a surgical sampling method to obtain precise wing primordium tissues for transcriptome analysis. We identified Wnt as a regulator of wing determination in the early second instar stage in the pea aphid. Inhibiting Wnt signaling via knockdown of Wnt2, Wnt11b, the Wnt receptor-encoding gene fz2 or the downstream targets vg and omb resulted in a decreased proportion of winged aphids. Activation of Wnt signaling via knockdown of miR-8, an inhibitor of the Wnt/Wg pathway, led to an increased proportion of winged aphids. Furthermore, the wing primordia of wingless nymphs underwent apoptosis in the early second instar, and cell death was activated by knockdown of fz2 under the wing-inducing condition. These results indicate that the developmental plasticity of aphid wings is modulated by the intrinsic Wnt pathway in response to environmental challenges.

Larvicidal proficiency of volatile compounds present in Commiphora wightii gum extract against Aedes aegypti (Linnaeus, 1762).

Aedes mosquitoes are the major cause of several vector-borne diseases in tropical and subtropical regions. Synthetic pesticides against these mosquitoes have certain limitations; hence, natural, eco-friendly, and safe larvicides obtained from plant resources are used to overcome these. In the present study, the larvicidal efficiency of Commiphora wightii against the fourth instar stage of the dengue fever mosquito Aedes aegypti (Linnaeus, 1762) was studied. The gum resin of C. wightii was collected using the borehole tapping method, and hexane extracts in different concentrations were prepared. The fourth-instar larvae were exposed to the extracts, and percent mortality, as well as LC20, LC50, and LC90, was calculated. Volatile compounds of the hexane gum extract were analyzed by Headspace GC/MS, and the sequence of the acetylcholine, Gamma-aminobutyric acid (GABA) receptor, and octopamine receptor subunit of A. aegypti was obtained. It was found that the hexane gum extract was toxic and lethal for larvae at different concentrations. Minimum mortality was observed at 164 µg mL-1 (10%/h), while maximum mortality was at 276 µg mL-1 (50%/h). The lethal concentrations LC20, LC50, and LC90 were 197.38 µg mL-1, 294.13 µg mL-1, and 540.15 µg mL-1, respectively. The GC/MS analysis confirmed the presence of diterpenes, monoterpenes, monoterpene alcohol, and sesquiterpenes in the gum samples, which are lethal for larvae due to their inhibitory activity on the acetylcholinesterase enzyme, GABA receptor, and octopamine receptor subunit. The use of commonly occurring plant gum for the control of mosquitoes was explored, and it was found that the gum of C. wightii had larvicidal activities and could be potentially insecticidal.

The pre- and postembryonic development of Artemia franciscana (Anostraca: Artemiidae).

Artemia franciscana is a universal live feed in aquaculture, and it has been reported as an invasive species in many Asian hypersaline ecosystems. The present observations illustrated the pre- and postembryonic development stages of the A. franciscana population confined to the Indian saltern of Kelambakkam. We observed their growth patterns during various hydration periods with specific time intervals. Results showed differences in the development stages with respect to unique identity. Interestingly, a period of hydration showed notable cellular movement toward clockwise positions in the hydrating cysts. After 10 h of hydration, blastocoel appeared, accelerating the dynamic route of nuclei movement. At the end of the invagination, the embryo burst out of the cyst, and a sequence of emerging stages was noted. With reference to light microscopic observations, a series of developmental stages were observed, and each instar was documented by developing limb buds of nauplii. Excitingly, the 10th and 11th instar stages reveal sexual differentiation between male and female individuals. Thus, the laboratory culture study clearly documented the different developmental stages with their specific characteristic features. However, further molecular study would provide a cellular basis for understanding the early development of A. franciscana.

Evaluation of Bed Disinfectants on Rearing Performance of Multivoltine Hybrid Mulberry Silkworm [NISTARI × (SK6×SK7)], in Kishanganj District, Bihar, India

The silkworm, (B. mori L). is highly susceptible to pathogens such as protozoa, virus, bacteria and fungus. To evaluate the various bed disinfectant viz, Vijetha, Sericilin, Labex, and Amla compare with untreated control for their suitability and standardization for the management of diseases during silkworm rearing. The rearing of silkworm multivoltine hybrid race [NISTARI × (SK6×SK7)] was carried out in the centre. In the present study the larvae treated with Labex @ 5 g/sq. ft. ½ an hour before resuming feeding had shortest (20.00 days) larval duration. Larvae weight higher (31.24 g) respectively at late 5th instar stage. Larval mortality was observed (25.93%) Effective rate of rearing (64.08%) and significantly lowest disease incidence (26.06%) was recorded.

Molecular characterization and expression patterns of a ryanodine receptor in soybean looper, Chrysodeixis includens.

Diamide insecticides, such as chlorantraniliprole, have been widely used to control insect pests by targeting the insect ryanodine receptor (RyR). Due to the efficacious insecticidal activity of diamides, as well as an increasing number of resistance cases, the molecular structure of RyR has been studied in many economically important insects. However, no research has been conducted on diamide resistance and RyR in the soybean looper, Chrysodeixis includens, a significant crop pest. In this study, we found moderate resistance to chlorantraniliprole in a field population from Puerto Rico and sequenced the full-length cDNA of the C. includens RyR gene, which encodes a 5124 amino acid-long protein. Genomic analysis revealed that the CincRyR gene consists of 113 exons, one of the largest exon numbers reported for RyR. Alternative splicing sites were detected in the cytosolic region. The protein sequence showed high similarity to other noctuid RyRs. Conserved structural features included the selectivity filter motif critical for ryanodine binding and ion conduction, as well as various domains involved in ion transport. Two mutation sites associated with diamide resistance in other insects were screened but not found in the Puerto Rico field populations or in the susceptible lab strain. Gene expression analysis indicated high expression of RyR in the third instar larval stage, particularly in muscle-containing tissues. Furthermore, exposure to a sublethal dose of chlorantraniliprole reduced RyR expression levels after 96 h. This study provides a molecular basis for understanding RyR structure and sheds light on potential mechanisms of diamide resistance in C. includens.

Effect of aqueous extract of Vicia faba peels on the mortality of immature stages and the inhibition of emergence of Culex quinquefasciatus (Diptera: Culicidae) mosquitoes.

The effectiveness of the aqueous extract (cold and boiled) of bean peels was studied, and the active compounds were determined by Fourier Transform Infrared Spectrophotometer (FT-IR), and concentrations (1, 3, 5) mg/ml were used when treating fourth-instar larvae and the pupae of Cx. quinquefasciatus mosquitoes and its effect on the percentage of the mortality of the fourth larval instar, the pupa stage and the inhibition of emergence of adults when treating the fourth larval instar and pupa stage of the insect in Kerbala governorate for March 2022 to control mosquitoes. Keywords: Culex quinquefasciatus, Plant extracts, Vicia faba.

Effect of aqueous extract of Vicia faba peels on the mortality of immature stages and the inhibition of emergence of Culex quinquefasciatus (Diptera: Culicidae) mosquitoes.

The effectiveness of the aqueous extract (cold and boiled) of bean peels was studied, and the active compounds were determined by Fourier Transform Infrared Spectrophotometer (FT-IR), and concentrations (1, 3, 5) mg/ml were used when treating fourth-instar larvae and the pupae of Cx. quinquefasciatus mosquitoes and its effect on the percentage of the mortality of the fourth larval instar, the pupa stage and the inhibition of emergence of adults when treating the fourth larval instar and pupa stage of the insect in Kerbala governorate for March 2022 to control mosquitoes. Keywords: Culex quinquefasciatus, Plant extracts, Vicia faba.

Plumeriaalba flower extract-mediated synthesis of recyclable chitosan-coated cadmium nanoparticles for pest control and dye degradation.

In the current scenario, many synthetic chemicals have used long-term to control pests and mosquitoes, leading to the resistance of strains and toxicity effect on human beings. To overcome the adverse problem in recent advances, the scientific community is looking into nanofabricated pesticides and mosquitoes. This study aims to synthesize the recyclable chitosan-coated cadmium nanoparticles (Ch-CdNps) using Plumeria alba flower extract, which was further applied for insecticidal and mosquitocidal activities. The synthesized Ch-CdNps were confirmed by UV spectroscopy and FTIR analysis. The XRD, TEM, and DLS results confirmed the crystallinity with a spherical shape at 80-100nm. The insecticidal activity proves that Ch-CdNps inhibitedHelicoverpa armigeraandSpodoptera lituraat 100ppm. In mosquitocidal, LC50 values of larvicidal of 1st instar were 4.116, 4.33, and 4.564µg/mL, and the remaining three stages of instars, pupicidal, adulticidal, longevity, fecundity, and ovicidal assays inhibit theAnopheles stephensifollowed byAedes aegyptiandCulex quinquefasciatus. Further, the first-order kinetics of photocatalytic degradation of methylene blue and methyl orange was confirmed. Based on the obtained results, Ch-CdNps can inhibit the pest, mosquitoes, and photocatalytic degradation.

Evaluation of larvicidal activity of Panchagavya, against the teak defoliator (<i>Hyblaea puera</i> Cramer) and skeletonizer (<i>Eutectona machaeralis</i> Walker) in a forest plantation

Panchagavya is an organic formulation, formed by merging five cow derivatives, such as dung, urine, milk, ghee, and curd, which promotes the growth of plants. The present investigation was aimed to determine the larvicidal efficacy of Panchagavya with varied concentrations against major pests of teak, Tectona grandis, singly, and combined with leaf extract of members of Meliaceae family, and coupled with extract of seaweed, in experimental research plots. Observations on occurrence of pests was also observed periodically and recorded. Treatments include 5% concentration of panchagavya (T1), which serves as a control and Panchagavya combined with varied dosage of other leaf crude extracts of Melia dubia (T2), Melia azedarach (T3), Azadirachta indica (T4), and a seaweed, Sargassum wightii (T5), with a concentration range of 1000-5000 ppm that were used as foliar application. Among the various pests, Hyblaea puera, and Eutectona machaeralis were found to be dominant, and the III instar larval stage were targeted for the management. Maximum larval mortality was observed with exposure to Panchagavya with crude extract of S. wightii, at an appropriate ratio (T5) against teak defoliator, Hyblaea puera. The per cent pest reduction was found to be 65% and 73% in 48 h and 72 h time interval. Similarly, higher level of larval mortality was recorded against skeletonizer (E. machaeralis) where the reduction per cent was recorded as 62% and 71% at 5000 ppm in (T5) within the interval of 48 h and 72 h. Consequently, a distinct individual lethal effect of Panchagavya (T1, control) against both pests was found to be 8%, 24%, and 46% with similar time frames. However, the efficacy of Panchagavya combined with extract of M. dubia, M. azedarach and A. indica exhibited statistically significant ability in larvicidal potential against H. puera. Whereas, treatments like T2, T3, and T4 showed 59, 67, and 62 % of larval mortality of E. machaeralis larva within the period of 72 h. The results of the study affirmed that the synergistic effects of Panchagavya coupled with seaweed extract at appropriate ratio proved to be effective against major pests of teak plantation.