Feeding Deterrent Research Articles

Significant Feeding Deterrent of Berberine from Tali kuning(Tinospora dissitiflora Diels) Against Two Subterranean Termites Coptotermes formosanus Shiraki and Reticulitermes speratus Kolbe

Antifeedant activities of berberine isolated from the chloroform fraction of Tali kuning (Tinospora dissitiflora Diels) were evaluated against two subterranean termites, Coptotermes formosanus Shiraki and Reticulitermes speratus Kolbe, respectively. The chloroform fraction of methanol extracts of Tali kuning and authentic berberine chloride were used for comparison. Three replicates and levels of concentrations, 12.5, 25, and 50 mg/ml, respectively, were employed. Filtepapers treated with three chemical substances were used to evaluate the mass losses of the filter paper consumed by the termites, and filter papers treated only with MeOH were used for control. Mass loss (MS), termite mortality (TM) and antifeedant index (AFI) were used to determine the antifeedant variables. The results indicated that regardless of three chemical substances tested, the MS recorded from C. formosanus Shiraki were 2.87 times higher than those of R. speratus Kolbe, and among three levels concentration, 50 mg/ml gave the lowest MS (2.13%). Authentic berberine chloride gave the highest TM (99%), followed by chloroform fraction (88%) and berberine (73%). Interestingly, all antifeedant variables employed in this study gave AFI values less than 20%, indicating significant feeding deterrent activity against two subterranean termites.

Antibacterial defenses and palatability of shallow-water Antarctic sponges

Marine sponges are exposed to predation as well as to a wide array of potentially harmful microorganisms, and therefore they often possess chemical activity against putative predators and/or pathogens. Some crude extracts from sponges are effective in avoiding microbial colonization or potential infections, and in protecting them against predation. Here, the antibacterial activity of 18 sponge species of Antarctic shallow-waters was tested against four Antarctic and four human pathogenic bacteria. Moreover, all sponge extracts were tested for feeding repellence against the seastar Odontaster validus, one of the main predators living in those habitats. All the sponges showed antibacterial activity against at least one bacterial isolate, although not all of them were active against pathogenic bacteria. The antibacterial effect against sympatric bacteria was stronger than to pathogenic bacteria. In contrast, feeding deterrence was low, with similar activities in both hydrophilic and lipophilic extracts. Only four sponges (Myxilla lyssostyla, Phorbas areolatus, Polymastia invaginata and Iophon sp.), presented repellent chemical defenses. Therefore, we conclude that chemical defenses are widespread in Antarctic shallow-water sponges, and in fact, these sponges are better protected against bacteria than against the seastar predator. We conclude that Antarctic sponges represent a valuable source of biological active compounds with pharmacological and potential ecological relevance.

Seasonal recruitment and survival strategies of Palisada cervicornis comb. nov. (Ceramiales, Rhodophyta) in coral reefs.

As marine tropical ecosystems deteriorate and lose biodiversity, their communities are shifting to being dominated by a few species, altering ecosystem's functioning and services. Macroalgae are becoming dominant on coral reefs, and are frequently observed outcompeting corals. Turf algal assemblages are the base of energy flow in these systems and one of the most abundant types of macroalgae on coral reefs, but little is known about their biology and diversity. Through molecular and morphological analyses, we identified the turf-forming species Laurencia cervicornis, and by studying seasonal recruitment and the impact of herbivorous fishes on its abundance, we describe its survival strategy. The molecular analyses used a total of 45 rbcL gene sequences including eight current genera within the Laurencia complex and two new sequences of L.cervicornis and strongly support the new combination of Palisada cervicornis comb. nov. In addition, a detailed morphological characterization including the description of reproductive structures is provided. Palisadacervicornis was seen recruiting in all seasons but was typically in low abundance. Specimens grown on tiles in fish exclosure cages were devoured in less than 4h when offered to fishes. Even though many species of the Laurencia complex have chemicals that deter herbivory, species within the genus Palisada lack feeding deterrents and thus are highly palatable. We suggest that P.cervicornis is a palatable species that seems to survive in the community by obtaining a size-refuge from herbivory within turf communities.

Repellent and toxic properties of plant oils and extracts on Cydalima perspectalis Walker (Lepidoptera: Crambidae)

Buxus plants in Europe become frequently infested by the Box tree moth, Cydalima perspectalis Walker (Lepidoptera: Crambidae) but applicable biological control methods are limited. To make a first step in preventing egg deposition on Buxus plants, seven essential oils (Carum carvi, Juniperus communis, Lavendula angustifolia, Melaleuca alternifolia, Pinus sylvestris, Rosmarinus officinalis and Thymus vulgaris), one seed oil (Sambucus nigra) and six plant extracts (Equisetum arvense, Juniperus communis, Quassia amara, Salvia officinalis, Tanacetum vulgare and Thymus vulgaris) were investigated on their potential to influence oviposition preference in the greenhouse. The four essential oils exhibiting the highest repellency values (RV = 0.61–0.94) were further assessed in laboratory leaf disc bioassays on larvae. Despite the strong repellent effect of S. nigra on female oviposition, no impact could be detected on the larvae. These were significantly susceptible to exposed leaf discs treated with T. vulgaris and M. alternifolia essential oils including feeding deterrence, survival and larval weight. T. vulgaris was the most effective oil considering both effects. The effective lethal concentration (LC50) of T. vulgaris was calculated to be 1% at 72 h. Our results suggest the possibility of using essential oils to protect Buxus plants in order to reduce the overall risk for defoliation by larval feeding.

Ladder-Shaped Ion Channel Ligands: Current State of Knowledge.

Ciguatoxins (CTX) and brevetoxins (BTX) are polycyclic ethereal compounds biosynthesized by the worldwide distributed planktonic and epibenthic dinoflagellates of Gambierdiscus and Karenia genera, correspondingly. Ciguatera, evoked by CTXs, is a type of ichthyosarcotoxism, which involves a variety of gastrointestinal and neurological symptoms, while BTXs cause so-called neurotoxic shellfish poisoning. Both types of toxins are reviewed together because of similar mechanisms of their action. These are the only molecules known to activate voltage-sensitive Na+-channels in mammals through a specific interaction with site 5 of its α-subunit and may compete for it, which results in an increase in neuronal excitability, neurotransmitter release and impairment of synaptic vesicle recycling. Most marine ciguatoxins potentiate Nav channels, but a considerable number of them, such as gambierol and maitotoxin, have been shown to affect another ion channel. Although the extrinsic function of these toxins is probably associated with the function of a feeding deterrent, it was suggested that their intrinsic function is coupled with the regulation of photosynthesis via light-harvesting complex II and thioredoxin. Antagonistic effects of BTXs and brevenal may provide evidence of their participation as positive and negative regulators of this mechanism.

Insect antagonistic bio-inoculants for natural control of leaf-mining insect pests of French beans

Fungal endophytes, specifically, Trichoderma asperellum, Beauveria bassiana and Metarhizium anisopliae ; strains M2RT4, S4SU1 and S4ST7, respectively, are known to deter aphid infestation and damage to leguminous crops, but no research exists on their biochemical profiles and effects on French bean ( Phaseolus vulgaris ) leaf miners. The objective of this study was to assess the ability of these endophytic bio-inoculants to produce extracellular enzymes, as well as determine their impact on French beans seedling emergence and growth, and leaf miner fecundity and pupation. Laboratory and greenhouse experiments were conduct at the International Centre of Insect Physiology and Ecology (ICIPE, Nairobi), and the University of Bonn (Germany). Bio-priming French bean seeds by soaking in fungal suspension containing 10 8 conidia/ ml for 4 hr positively impacted on seedling vigour. Six weeks after germination, all bio-inoculant treatments improved nodulation by 1.5-1.7 folds, while S4SU1 and M2TR4 improved shoot biomass by ~ 2g. In vitro , spore suspensions of these isolates were highly toxic to leaf miner larvae, often resulting in high mortalities and a suppression of pupation by over 70%. All tested isolates exhibited protease (Index=1.22), lipase (Index=1.32) and cellulase (Index=1.06) activities; with M. anisopliae being the best enzyme secretor when cultured under dark conditions on enzyme-specific substrate for 7-14 days. In vivo B. bassiana -primed seedlings deterred larval feeding and development, resulting in reduced number of larvae, pupae and adults, by 65.3, 43.2 and 54.0%, respectively. For the first time, this study showed that bio-priming French bean seeds with bio-inoculants can boost P. vulgaris growth and nodulation, consequently altering its interaction and response to leaf miner infestation, feeding and damage to treated seedlings. These bioinoculants, thus, hold great potential as crop protection agents and could be safely used for priming seeds prior to planting, if leaf mining damages and associated yield losses in French beans are to be minimised in an environmentally sound manner. Further studies should be undertaken to elucidate the mechanisms involved in plant growth promotion, nodulation and insect feeding deterrence. Key Words : Bio-priming, endophytes, Liriomyza spp., nodulation

Ovicidal, larvicidal, and behavioural effects of some plant essential oils on diamondback moth (Lepidoptera: Plutellidae)

AbstractAlternatives to synthetic insecticides are desirable for management of diamondback moth, Plutella xylostella (Linnaeus) (Lepidoptera: Plutellidae), an insect pest of global importance. Many essential oils derived from aromatic plants have demonstrated toxicity and behaviour altering effects on insect pests, and are considered low-risk alternatives to synthetic insecticides. We conducted laboratory experiments to determine the biological activity of several low-cost, commercially available essential oils against P. xylostella. Experiments testing ovicidal effects, larvicidal effects, larval feeding deterrence, and adult oviposition deterrence were done with essential oils derived from Artemisia abrotanum Linnaeus (Asteraceae), balsam fir (Abies balsamea Linnaeus (Pinaceae)), black pepper (Piper nigrum Linnaeus (Piperaceae)), eucalyptus (Eucalyptus polybractea (Baker) (Myrtaceae)), garlic (Allium sativum Linnaeus (Amaryllidaceae)), rosewood (a blend of different oil constituents), tansy (Tanacetum vulgare Linnaeus (Asteraceae)), and thyme (Thymus zygis Linnaeus (Lamiaceae)), using concentrations of 1, 2.5, and 5% v/v. Although all essential oils had some level of bioactivity against certain P. xylostella life stages, essential oils from garlic, rosewood, and thyme were most effective overall, demonstrating significant ovicidal and larvicidal activity, as well as deterrent effects on larval feeding and settling behaviour, and adult oviposition. Although variable phytotoxicity was observed with essential oils at 2.5% and 5% v/v concentrations, the results suggest that rosewood, garlic, and thyme essential oils have potential in management of P. xylostella.

Chemical Constituents of Supercritical Extracts from Alpinia officinarum and the Feeding Deterrent Activity against Tribolium castaneum.

Alpinia officinarum has been confirmed to possess bioactivities against some pests. In this work, a sample was obtained from A. officinarum rhizomes by supercritical fluid CO2 extraction (SFE). According to GC-MS analysis, the main chemical components for SFE-sample included benzylacetone (26.77%), 1,7-diphenyl-5-hydroxy-3-heptanone (17.78%), guaiacylacetone (10.03%) and benzenepropanal (7.42%). The essential oil of A. officinarum rhizomes (LD50 = 20.71 μg/adult) exhibited more contact toxicity than SFE extract (LD50 = 82.72 μg/adult) against Tribolium castaneum. From SFE extracts, one new compound, 1-phenyl-4-(16,17-dimethyl-9,13-octadiene)-5-isopentenyl-7-(4”-methoxyl-3”-hydroxyl-phenyl)-3-heptanone (3), together with five known compounds identified as 5-hydroxy-1,7-diphenyl-3-heptanone (1), 1,7-diphenyl-4-hepten-3-one (2), galangin (4), galangin-3-methyl ether (5) and pinocembrin (6), were isolated and their feeding deterrent activities against T. castaneum adults were assessed. It was found that compounds 1–6 had feeding deterrent activities against T. castaneum with feeding deterrent indices of 18.21%, 18.94%, 19.79%, 26.99%, 20.34%, and 35.81%, respectively, at the concentration of 1500 ppm. Hence, the essential oil and SFE extracts/compounds of A. officinarum rhizomes represent promising alternatives in the control of T. castaneum adults.

Chemosensory Responses to the Repellent Nepeta Essential Oil and Its Major Component Nepetalactone by Aedes aegypti (Diptera: Culicidae), a Vector of Zika Virus.

Nepeta essential oil (Neo; catnip) and its major component, nepetalactone, have long been known to repel insects including mosquitoes. However, the neural mechanisms through which these repellents are detected by mosquitoes, including the yellow fever mosquito Aedes aegypti (L.), an important vector of Zika virus, were poorly understood. Here we show that Neo volatiles activate olfactory receptor neurons within the basiconic sensilla on the maxillary palps of female Ae. aegypti. A gustatory receptor neuron sensitive to the feeding deterrent quinine and housed within sensilla on the labella of females was activated by both Neo and nepetalactone. Activity of a second gustatory receptor neuron sensitive to the feeding stimulant sucrose was suppressed by both repellents. Our results provide neural pathways for the reported spatial repellency and feeding deterrence of these repellents. A better understanding of the neural input through which female mosquitoes make decisions to feed will facilitate design of new repellents and management strategies involving their use.

Assessing the potential of non-harmful, natural feeding deterrents tested on captive primates

ABSTRACTCrop damage by non-human primates can cause friction between local people, government wildlife agencies and conservationists. Consequently, developing effective, non-lethal methods to protect crops against primate foraging could benefit farmers, reduce conflicts between interest groups, and even promote primate conservation The purpose of this research was to (1) develop a simple, economical protocol for testing the deterrent properties of non-lethal plant substances on captive primates prior to testing in the field; (2) examine the preliminary effectiveness of neem (Azadirachta indica) and ocimum (Ocimum kilimandscharicum) essential oils, and spent coffee grounds (SCGs) as feeding deterrents in captive macaques. The test methods developed involved exposing primates to possible feeding deterrents whilst feeding and comparing to a control. This was used to identify likely repellent substances, which could then be tested in the field to determine their effectiveness against crop damage. SCGs were most effective at deterring the macaques; ocimum and neem essential oils were less effective, though animals appeared less willing to access food when protected by these oils than they were under control conditions.

Secondary metabolome and its defensive role in the aeolidoidean Phyllodesmium longicirrum, (Gastropoda, Heterobranchia, Nudibranchia).

Phyllodesmium longicirrum is the largest aeolidoidean species known to date, and extremely rich in terpenoid chemistry. Herein we report the isolation of a total of 19 secondary metabolites from a single specimen of this species, i.e., steroids 1–4, cembranoid diterpenes 5–13, complex biscembranoids 14 and 15, and the chatancin-type diterpenes 16–19. These compounds resemble those from soft corals of the genus Sarcophyton, of which to date, however, only S. trocheliophorum is described as a food source for P. longicirrum. Fish feeding deterrent activity was determined using the tropical puffer fish Canthigaster solandri, and showed activity for (2S)-isosarcophytoxide (10), cembranoid bisepoxide 12 and 4-oxochatancin (16). Determining the metabolome of P. longicirrum and its bioactivity, makes it evident that this seemingly vulnerable soft bodied animal is well protected from fish by its chemical arsenal.

Growth inhibitory and antifeedant effects of sublethal concentrations of toosendanin on the rotifer Brachionus plicatilis

Toosendanin has been suggested as a potential agent for controlling zooplankton contamination in microalgal cultivation. Growth inhibitory and antifeedant influences of toosendanin on the rotifer Brachionus plicatilis were investigated. Sublethal concentrations of toosendanin (1.76–2.59 mg m−3) reduced population abundance of rotifers, decreased the lorica length and width, and shrank the body size of survivors notably. No changes were observed in the amictic egg sizes, although the egg production per female rotifer was decreased by toosendanin. Exposure to toosendanin for 4 h significantly decreased the rotifer chlorophyll consumption per individual, indicating the antifeedant effect on rotifers. Analysis on the digestive enzymes showed that exposure to toosendanin had no effect on cellulose activity, but reduced the activities of diastase, pepsase and tryptase in rotifer homogenate. In addition, the half-saturation constant (Km) of tryptase was increased and the maximum velocity (Vmax) of pepsase was decreased by toosendanin, suggesting the direct inhibition of these two proteases by toosendanin in B. plicatilis. This may contribute to the feeding deterrent property of toosendanin on rotifers. The present study heralds the very beginning of studies regarding the toxic mechanism of toosendanin on rotifers, and will accelerate its potential uses for zooplankton extermination in microalgal cultivation.

ANTIFEEDANT EFFECTS OF VITEX NEGUNDO L. LEAF EXTRACTS ON THE STORED PRODUCT PEST, TRIBOLIUM CASTANEUM H. (COLEOPTERA: TENEBRIONIDAE)

Objective: This study aims to evaluate the nutritional and feeding deterrence indices of Tribolium castaneum adults caused by petroleum ether and methanol extracts of Vitex negundo.Methods: A modified method of flour disc bioassay was carried out to study the antifeedant activities of both the extracts on the stored product pest, T. castaneum. In this bioassay, the insects were allowed to feed on wheat flour treated with various concentrations (1.25%, 2.5% and 5%) of petroleum ether and methanol extracts of V. negundo (VPE and VME) for 24 h in ‘no choice’ chambers. The effects of different concentrations of the extracts on relative growth rate and relative consumption rate of T. castaneum and the difference between the activities of two extracts were statistically analysed and compared by analysis of covariance (ANCOVA). Similarly, the comparison of the activities of VPE and VME, and their dose effects on the efficiency of conversion of ingested food and feeding deterrence indices of the insects were analysed by analysis of variance (ANOVA).Results: VPE and VME significantly affected growth, consumption and utilisation of food, and caused antifeedancy in T. castaneum. It was also found that both the extracts resulted in a slight reduction in growth rate of the insect, compared with that of the control. The reductions in relative growth rate (RGR) (P=0.37) and relative food consumption rate (RCR) (P<0.05) were more prominent for 2.5% and 5% of both the extracts. In nutritional studies, it was found that increase in the concentration (P<0.05) resulted in an increase in the efficiency of conversion of ingested food (ECI) significantly with both the extracts. The RGR, RCR and ECI of the insects were found to be similar with both the extracts. The extracts showed dose-dependent feeding deterrence index (FDI) for this insect (P<0.001). The activity was found to be similar with both the extracts (P=0.07).Conclusion: The present study reveals that both VPE and VME show significant antifeedancy in T. castaneum and thus they can effectively be used for the protection of grains from insects.

Potential benefits of phytochemicals against Alzheimer's disease.

Our current therapeutic drugs for Alzheimer's disease are predominantly derived from the alkaloid class of plant phytochemicals. These drugs, such as galantamine and rivastigmine, attenuate the decline in the cholinergic system but, as the alkaloids occupy the most dangerous end of the phytochemical spectrum (indeed they function as feeding deterrents and poisons to other organisms within the plant itself), they are often associated with unpleasant side effects. In addition, these cholinesterase inhibiting alkaloids target only one system in a disorder, which is typified by multifactorial deficits. The present paper will look at the more benign terpene (such as Ginkgo biloba, Ginseng, Melissa officinalis (lemon balm) and Salvia lavandulaefolia (sage)) and phenolic (such as resveratrol) phytochemicals; arguing that they offer a safer alternative and that, as well as demonstrating efficacy in cholinesterase inhibition, these phytochemicals are able to target other salient systems such as cerebral blood flow, free radical scavenging, anti-inflammation, inhibition of amyloid-β neurotoxicity, glucoregulation and interaction with other neurotransmitters (such as γ-aminobutyric acid) and signalling pathways (e.g. via kinase enzymes).

Identification and Characterization of a 25 kDa Protein That Is Indispensable for the Efficient Saccharification of Eisenia bicyclis in the Digestive Fluid of Aplysia kurodai.

The digestive fluid of the sea hare Aplysia kurodai can liberate approximately 2.5 mg of glucose from 10 mg of dried Eisenia bicyclis powder. Although laminaran, a major storage polysaccharide in E. bicyclis, is easily digested to glucose by the synergistic action of the 110 and 210 kDa A. kurodai β-glucosidases (BGLs), glucose is not liberated from E. bicyclis by direct incubation with these BGLs. To clarify this discrepancy, we searched for an Eisenia hydrolysis enhancing protein (EHEP) in the digestive fluid of A. kurodai. A novel 25 kDa protein that enhances E. bicyclis saccharification by β-glucosidases was purified to a homogeneous state from the digestive fluid of A. kurodai, and its cDNA was cloned from total cDNAs reverse-transcribed from hepatopancreas total RNA. The E. bicyclis extract strongly inhibited BGLs, suggesting some compound within this brown alga functioned as a feeding deterrent. However, when E. bicyclis was incubated with BGLs in the presence of EHEP, glucose production was markedly increased. As E. bicyclis is rich in phlorotannin, which are only found in brown algae, our study suggested that these compounds are the main BGL inhibitors in E. bicyclis extract. EHEP protects BGLs from phlorotannin inhibition by binding to phlorotannins and forming an insoluble complex with phloroglucinol and phlorotannins. These findings indicated that EHEP plays a key role in the saccharification of brown seaweeds containing phlorotannins in the digestive fluid of A. kurodai. This is the first report of EHEP as a phlorotannin-binding protein that protects BGLs from inhibition.

Antifeedant activity of red clover root isoflavonoids on Hylastinus obscurus

In the last decade, there has been increasing interest in investigating the impact of flavonoids on insects, specifically for pest control. In this study, we investigated the impact of isoflavonoids upon the feeding behavior of the clover root borer, Hylastinus obscurus Marsham (Coleoptera: Curculionidae), which is one of the most serious global pests associated with red clover, Trifolium pratense L. Four aglycones isoflavonoids: genistein (1), formononetin (2), daidzein (3) and biochanin A (4) were isolated and identified by HPLC, from roots of two Chilean red clover cultivars. The first two compounds, formononetin (2) and genistein (1), showed high feeding deterrent activity when they were evaluated in artificial diets. This antifeedant effect of isoflavones on feeding behavior of H. obscurus suggests that they are responsible for a decreasedin insect weight gain as compared with the control. This information could be useful respectively, to farmers and researcher to produce and create plants resistant to curculionid

Gut content, fatty acid, and stable isotope analyses reveal dietary sources of macroalgal-associated amphipods along the western Antarctic Peninsula

Shallow water subtidal marine communities along the western Antarctic Peninsula are characterized by dense beds of macroalgae and strikingly dense assemblages of associated amphipods. However, direct grazing by amphipods on the dominant macroalgae is unlikely as most of these algae elaborate secondary metabolites known to be herbivore feeding deterrents. What resources, then, support this vast macroalgal-associated amphipod assemblage? We addressed this question by analyzing the gut contents, fatty acids, and stable isotopic ratios of 15 different amphipod species associated with the macrophyte community. The δ15N and δ13C stable isotope values revealed that most of the abundant species of amphipods are primary consumers whose ultimate carbon source is derived from some combination of brown macroalgae, epiphytic diatoms, and endo/epiphytic filamentous algae. Gut contents revealed that a large percentage of the amphipod diets are comprised of diatoms and macroalgal tissues, both filamentous and multiseriate. Fatty acid analysis corroborated our conclusions based on stable isotope and gut content data, demonstrating the importance of diatoms to assimilated material, but also highlighting the rich diversity of diets within the macroalgal-associated amphipod assemblage. Our findings suggest that amphipods routinely clean their host macrophytes of potentially harmful epiphytes, including both diatoms and emergent filaments from brown algal endophytes. Some prominent species of amphipods may also derive a small percentage of their carbon from palatable and, in one case, unpalatable, chemically defended red algae. These results, combined with previous studies showing that the amphipods gain refuge from predators by associating with unpalatable macroalgae, support the hypothesis that amphipods along the western Antarctic Peninsula are living in mutualism with their macrophyte hosts rather than consuming the host directly.

A glycoprotein α-amylase inhibitor from Withania somnifera differentially inhibits various α-amylases and affects the growth and development of Tribolium castaneum.

Identification and characterisation of plant defensive molecules enrich our resources to design crop protection strategies. In particular, plant-derived proteinaceous inhibitor(s) of insect digestive enzymes appear to be a safe, sustainable and attractive option. A glycoprotein having non-competitive α-amylase inhibitory activity with a molecular weight of 8.3 kDa was isolated and purified from seeds of Withania somnifera α-amylase inhibitor (WSAI). Its mass spectrometry analysis revealed 59% sequence coverage with Wrightide II-type α-amylase inhibitor from Wrightia religiosa. A dose-dependent inhibition of α-amylases from Aspergillus oryzae, Bacillus subtilis, Helicoverpa armigera and Tribolium castaneum was recorded. Interestingly, WSAI did not inhibit human salivary α-amylase significantly. When adults of T. castaneum were fed with WSAI (1.6 mg g-1 ), decrease in consumption, growth and efficiency of conversion of ingested food was evident, along with over fourfold increases in feeding deterrence index. A decline in larval residual α-amylase activity after feeding of WSAI resulted in a reduction in longevity of T. castaneum. The study reflects the significance of WSAI in affecting the overall growth and development of T. castaneum. Pre- and post-harvest pest resistive capability makes WSAI a potential candidate for insect pest management. Further, the effectiveness of this inhibitor could be explored either in formulations or through a transgenic approach. © 2016 Society of Chemical Industry.

Bioefficacy of cadmium and lead on cotton leafworm Spodoptera littoralis (Lepidoptera: Noctuidae) larvae

The sensitivity of Spodoptera littoralis second and fourth instar larvae to the heavy metals cadmium (Cd) and lead (Pb) was investigated under laboratory conditions. Both Cd and Pb, even, at very low concentrations, had relatively high toxic effects on S. littoralis larvae. Cd was more toxic to S. littoralis larvae than Pb. In addition, the mean percentage feeding deterrence (FDI%) of Cd and Pb was concentration-dependent. The nutritional indices (consumption index, growth rate, efficiency of converted ingested and digested food, and approximate digestibility) of S. littoralis second and fourth instar larvae were more affected in Cd-treatments compared with those of Pb-treatments. Therefore, the presence of such heavy metals in the environment would exert an adverse impact on S. littoralis larvae and their development.

Antifungal and antiproliferative activities of endophytic fungi isolated from the leaves of Markhamia tomentosa

Context: Plants harbor endophytes with potential bioactivity. Markhamia tomentosa (Benth) K. Schum ex. Engl. (Bignoniaceae) is reported to possess antioxidant, anti-inflammatory and anticancer activities. Objective: The antifungal and antiproliferative properties of endophytic fungi extracts and fractions from M. tomentosa were evaluated. Material and methods: Endophytic fungi were isolated from the leaves of M. tomentosa and identified by ITS-rDNA sequence analysis. The antagonistic effect of the fungal strains was investigated against pathogenic fungi viz, Fusarium oxysporum, Sclerotinia sclerotiorium, Rhizoctonia solani, and Botrytis cinerea using the dual culture assay for 5–7 days. Antiproliferative effect of the fungal extracts and fractions (3.91–250 μg/mL) on HeLa cancer cell line was tested and IC50 was calculated. Poisoning food assay and antifeedant activity against the pathogenic fungi and Spodoptera litura larvae, for 7 days and 2 h, respectively, was also tested at concentrations of 250, 500 and 1000 μg/mL. Results: Fungal endophytes Trichoderma longibrachiatum and Syncephalastrum racemosum were isolated from the leaves of M. tomentosa. Isolated endophytic fungal strains and solvent extracts showed MIC value of 1000 μg/mL against tested pathogenic fungi in the dual culture and poisoning food assays. Methanol fraction of S. racemosum isolate showed the most effective antiproliferative activity with IC50 of 43.56 μg/mL. Minimal feeding deterrent activity against S. litura larvae was also observed. Discussion and conclusion: These findings showed that the leaves of Markhamia tomentosa harbor strains of endophytic fungi with promising health benefits, and suggest their antifungal and antiproliferative effects against pathogenic fungi and HeLa cancer cell line.