Feeding Deterrent Effects Research Articles

Bioactive peptides inhibit feeding activity in the grey garden slug, Deroceras reticulatum.

The grey garden slug (Deroceras reticulatum) is considered the most damaging slug pest in global agriculture. Control methods primarily rely on chemical pesticides, which pose environmental risks and potential hazards to human health. There is a need for sustainable management alternatives such as biologically-based slug control options. However, the efficacy of nonchemical measures for controlling pest slug populations remains limited, particularly in the context of variable outdoor conditions. Neuropeptides and their corresponding receptors have been proposed as promising biological targets for the development of new pest management strategies. A total of 23 bioactive peptides belonging to the PRX family, previously identified from the grey garden slug, D. reticulatum, were injected into or fed to this species. The detrimental effects of these peptides, including a reduction in body weight and an inhibition of feeding activity, were evaluated in feeding choice tests with D. reticulatum. Furthermore, the bioactive peptide formulated with a lipid particle demonstrated a feeding deterrent effect. One of the myomodulin (MM) peptides, APPLPRY, demonstrated a significant reduction in feeding activity, resulting in a reduction in slug weight or mortality in just 30 min. The results represent the first evidence of a bioactive peptide having detrimental effects on D. reticulatum including causing feeding deterrent for this slug pest. The in vivo results provide insights into the potential development of active ingredients for managing slugs in the field. © 2024 Society of Chemical Industry.

Insecticidal, antifeedant, and repellent effect of Lavandula mairei var. antiatlantica essential oil and its major component carvacrol against Sitophilusoryzae

The genus Lavandula encompasses plants commonly known for their bioactivities and applications as insecticides. Despite this recognition, certain species such as Lavandula mairei Humbert have received no attention. For this reason, our study offers a close insight into the chemical profile, insecticidal (i.e. fumigant and contact toxicity), repellent, and antifeedant effect of Lavandula mairei var. antiatlantica (Maire) Maire essential oil (LMEO) against Sitophilus oryzae (L.), a major stored product insect. Additionally, the major compound of LMEO, i.e. carvacrol, was also tested for the aforementioned bioactivities. In the fumigant bioassays LMEO and carvacrol showed LC50 values of 69.5 and 69.3 μL/L of air, respectively, after 72 h while in the contact bioassays LC50 values of 0.14 and 0.117 μL/insect, respectively, after 24 h. In terms of antifeedant effect, carvacrol and LMEO significantly influenced the Feeding Deterrent Index (FDI) recording 83.2 and 55.0%, respectively, at a concentration of 3.2%. Furthermore, a notable reduction of 5.5 and 2.1-fold in Relative Consumption Rate (RCR) was observed for carvacrol and LMEO, respectively, compared to the control. Regarding the repellent effect, carvacrol and LMEO exhibited percentages of repellency (PR) of 94 and 82%, respectively, at 0.312 μL/cm2 after 24 h. In conclusion, our study underscores the significant insecticidal, feeding deterrent, and repellent effects of LMEO and its major compound against the rice weevil. Its cultivable potential and bioactivities confirmed through this study promote its use as sustainable pest control solution.

Evaluation of Philippine-sourced clay particles as coating agents of cacao pods and carrier of entomopathogen against cacao pest, Helopeltis bakeri Poppius

Evaluation of the efficacy of clay particles as a coating agent of cacao pods and carrier of entomopathogen, Metarhizium anisopliae Sorokin, was conducted for the control of cacao mirid bug (CMB), Helopeltis bakeri Poppius. Choice and no-choice tests were performed to evaluate Philippine-sourced clay particles as a coating agent of cacao pods to deter CMB feeding, in comparison with the commercially available particle film (US kaolin Surround®). To determine the most efficient local clay particles in protecting the pods from CMB feeding, six (6) treatments were evaluated namely, Philippine-sourced kaolin (PH kaolin), zeolite (PH zeolite), bentonite (PH bentonite), US kaolin, water (negative control), and a commercial synthetic insecticide thiamethoxam (Actara®) (positive control). All treatments were subjected to choice and no-choice tests. Among the Philippine clay particles tested in both tests, PH zeolite showed significant coating and deterred CMB from feeding. Since the US Kaolin and zeolite showed significant feeding deterrent effects on CMB, these treatments were tested as carriers of entomopathogenic fungi, M. anisopliae, including water (negative control) and thiamethoxam. Results showed that zeolite is a good carrier of the spores of M. anisopliae as its effects to deter CMB feeding started 24 hours after exposure. This was confirmed by positive M. anisopliae extraction from dead CMB through potato dextrose agar (PDA) plating.

Phenolic secondary metabolites from Acorus calamus (Acorales: Acoraceae) rhizomes: the feeding deterrents for Spodoptera litura (Lepidoptera: Noctuidae).

Spodoptera litura Fabricius (Lepidoptera: Noctuidae) is one of the most destructive pests of various crops cultivated in Thailand. Spodoptera litura larvae, at early stages, attack the leaves and feed on every part of infested crops in later stages. Acorus calamus essential oil contains toxic asarones, which are generalistic cytotoxic compounds. However, the present study is the first attempt to look at safer metabolites from the rhizomes that could deter insect feeding. The objective was to use such compounds as safer residues on crops that would prevent the feeding of herbivorous lepidopterans. Accordingly, phenolic metabolites were isolated and evaluated to establish the feeding deterrence against polyphagous S. litura larvae. Methanol extract of A. calamus, chrysin, and 4-hydroxy acetophenone compounds were the most effective feeding deterrents with FD50 of 87.18, 10.33, and 70.77 µg/cm2, respectively, after 4 h of feeding on treated kale leaves in a no-choice leaf disc assay. Chrysin also reduced carboxylesterase activities (1.37-fold), whereas A. calamus methanol extract reduced glutathione-S-transferase activities (1.44-fold). Some larvae were also seen dead if they consumed the treated kale leaves. Feeding deterrent activity in the methanol extract of A. calamus was due to chrysin and 4-hydroxy acetophenone. The large-scale utilization of such compounds could help develop feeding deterrent strategies in the integrated pest management of lepidopterans.

The deterrent ability of Xenorhabdus nematophila and Photorhabdus laumondii compounds as a potential novel tool for Lobesia botrana (Lepidoptera: Tortricidae) management

The grapevine moth, Lobesia botrana (Lepidoptera: Tortricidae), is a critical pest for vineyards and causes significant economic losses in wine-growing areas worldwide. Identifying and developing novel semiochemical cues (e.g. volatile bacterial compounds) which modify the ovipositional and trophic behaviour of L. botrana in vineyard fields could be a novel control alternative in viticulture. Xenorhabdus spp. and Photorhabdus spp. are becoming one of the best-studied bacterial species due to their potential interest in producing toxins and deterrent factors. In this study, we investigated the effect of the deterrent compounds produced by Xenorhabdus nematophila and Photorhabdus laumondii on the ovipositional moth behaviour and the larval feeding preference of L. botrana. Along with the in-vitro bioassays performed, we screened the potential use of 3 d cell-free bacterial supernatants and 3 and 5 d unfiltered bacterial ferments. In addition, we tested two application systems: (i) contact application of the bacterial compounds and (ii) volatile bacterial compounds application. Our findings indicate that the deterrent effectiveness varied with bacterial species, the use of bacterial cell-free supernatants or unfiltered fermentation product, and the culture times. Grapes soaked in the 3 d X. nematophila and P. laumondii ferments had ∼ 55% and ∼ 95% fewer eggs laid than the control, respectively. Likewise, the volatile compounds emitted by the 5 d P. laumondii fermentations resulted in ∼ 100% avoidance of L. botrana ovipositional activity for three days. Furthermore, both bacterial fermentation products have larval feeding deterrent effects (∼65% of the larva chose the control grapes), and they significantly reduced the severity of damage caused by third instar larva in treated grapes. This study provides insightful information about a novel bacteria-based tool which can be used as an eco-friendly and economical alternative in both organic and integrated control of L. botrana in vineyard.

Functional analysis of a bitter gustatory receptor highly expressed in the larval maxillary galea of Helicoverpa armigera.

Many plant secondary substances are feeding deterrents for insects and play a key role in the selection of host plants. The taste sensilla of phytophagous insects contain gustatory sensory neurons sensitive to deterrents but the molecular basis of deterrent chemoreception remains unknown. We investigated the function of Gr180, the most highly expressed bitter gustatory receptor in the maxillary galea of Helicoverpa armigera larvae. Functional analyses using the Xenopus oocyte expression system and two-electrode voltage clamp revealed that the oocytes expressing Gr180 responded to coumarin. Tip recording results showed that the medial sensilla styloconica of the maxilla of fifth instar larvae exhibited electrophysiological responses to coumarin. Two-choice feeding bioassays confirmed that coumarin inhibited larval feeding. A homozygous mutant strain of H. armigera with truncated Gr180 proteins (Gr180−/−) was established using the CRISPR-Cas9 system. The responses of the medial sensilla styloconica in Gr180−/− to coumarin were almost abolished, and the responses to sinigrin and strychnine were also significantly decreased. Knockout of Gr180 alleviated the feeding deterrent effects of coumarin, sinigrin, and strychnine. Thus, we conclude that Gr180 is a receptor responding to coumarin,and also participates in sensing sinigrin and strychnine. These results enhance our understanding of the gustatory sensing mechanisms of phytophagous insects to deterrents.

Mycorrhiza-induced mycocypins of Laccaria bicolor are potent protease inhibitors with nematotoxic and collembola antifeedant activity.

Fungivory of mycorrhizal hyphae has a significant impact on fungal fitness and, by extension, on nutrient transfer between fungi and host plants in natural ecosystems. Mycorrhizal fungi have therefore evolved an arsenal of chemical compounds that are hypothesized to protect the hyphal tissues from being eaten, such as the protease inhibitors mycocypins. The genome of the ectomycorrhizal fungus Laccaria bicolor has an unusually high number of mycocypin-encoding genes. We have characterized the evolution of this class of proteins, identified those induced by symbiosis with a host plant and characterized the biochemical properties of two upregulated L. bicolor mycocypins. More than half of L. bicolor mycocypin-encoding genes are differentially expressed during symbiosis or fruiting body formation. We show that two L. bicolor mycocypins that are strongly induced during symbiosis are cysteine protease inhibitors and exhibit similar but distinct localization in fungal tissues at different developmental stages and during interaction with a host plant. Moreover, we show that these L. bicolor mycocypins have toxic and feeding deterrent effect on nematodes and collembolans, respectively. Therefore, L. bicolor mycocypins may be part of a mechanism by which this species deters grazing by different members of the soil food web.

Fumigant Toxicity and Feeding Deterrent Activity of Essential Oils from Lavandula dentata, Juniperus procera, and Mentha longifolia against the Land Snail Monacha obstructa

Land mollusks are one of the most destructive agricultural pests worldwide, the management of which depends on synthetic molluscicides. However, many of these molluscicides are harmful to nontarget organisms. Hence, there is a need to develop alternative ecofriendly molluscicides that are less impactful toward nontarget organisms. So, an investigation into the fumigant toxicity and feeding deterrent effect of essential oils (EOs) from Lavandula dentata L. (Lamiaceae), Juniperus procera Hochst. (Cupressaceae), and Mentha longifolia (L.) Huds. (Lamiaceae) against the land snail Monacha obstructa (Pfeiffer, 1842) (Hygromiidae) was performed. L. dentata EO exhibited the highest fumigant toxicity with LC50 values of 8.68 μL/L air and 7.24 μL/L air after 24 h and 48 h exposure periods, respectively. Its main components were camphor, 1,8-cineole, fenchone, and β-myrecene. The fumigant toxicity of J. procera EO was lower than that of L. dentata, with LC50 values of 25.63 μL/L air and 20.11 μL/L air after 24 h and 48 h exposure periods, respectively. The major constituents of J. procera EO were α-pinene, p-cymene, and β-ocimene. The analysis of M. longifolia EO showed that pulegone, and menthol were the major constituents. However, it displayed no fumigant toxicity up to 50 μL/L air. The three EOs exhibited a strong feeding deterrent effect at sublethal concentrations. The EOs extracted from L. dentata, J. procera and M. longifolia are promising ecofriendly botanical molluscicides against the land snail M. obstructa.

Repellent and toxic effects of Salvia rosmarinus oil against Liriomyza sativae

AbstractThe vegetable leafminer (VLM) Liriomyza sativae Blanchard is a troublesome pest of vegetable and ornamental plants worldwide. Resistance development and environmental pollution from the overuse of chemical insecticides have driven interest in alternative control strategies for this pest. Secondary metabolites derived from aromatic nonhost plants are recognised components of the plant defence system against herbivores. The essential oils derived from aromatic plants not only repel insects but also have toxic effects against various insect pests, yet little is known about their effects against leafminers. The major constituents of the essential oil extracted from rosemary leaves by hydrodistillation were identified by GC–MS. The behavioural responses of VLM adults to the rosemary essential oil (REO) were explored with Y‐tube olfactometer experiments, and the oviposition and feeding deterrent effects of REO against adults were studied using no‐choice cage tests. Dipping methods were used to determine the toxicity of REO and Matrine (a commercial botanical pesticide) against VLM eggs, larvae and pupae, while glass‐vial bioassays were used for adults. The identified major constituents of the cineoliferum chemotype of REO were 1,8‐cineole (23.53%), pinene (23.45%), (S)‐(−)‐verbenone (12.84%) and borneol (7.47%). REO repelled leafminer adults. Sublethal concentrations of REO deterred oviposition and feeding by adults. Adults were more susceptible than other developmental stages to toxicity of REO and Matrine. Female adults were more sensitive than males, based on EC50 values at 24 and 48 hr after treatment. Rosemary essential oil is a behaviour‐modifying stimulus potentially useful in a “push‐pull” strategy for L. sativae control, and as an alternative to synthetic chemical insecticides due to its low toxicity and high efficacy in the control of VLM.

Antifeedant Activity and Biochemical Responses in Spodopteraexigua H\xfcbner (Lepidoptera: Noctuidae) Infesting Broccoli, Brassicaoleracea var. alboglabra exposed to Piperribesioides Wall Extracts and Allelochemicals

BackgroundSpodoptera exigua Hübner (Lepidoptera: Noctuidae) is a widely occurring insect pest of several crops conventionally controlled by pyrethroids and organophosphates hazardous for the environment and human health. Thus, the alternatives are biocide-based phytochemicals. Accordingly, the Piper ribesioides Wall. (Piperales: Piperaceae) plant, well distributed in the northern regions of Thailand (Nan Province), was used due to its known bioactivity against insects. The objective was to determine the feeding deterrent activity of P. ribesioides extracts and isolated allelochemicals under laboratory conditions and correlate the efficacy under greenhouse conditions after the extracts were applied to S. exigua larvae infesting potted Brassica oleracea var. alboglabra (Bailey) Musil plants. Another objective was to look at the impact of spray applications on detoxification enzymes to check the possibility of resistance development against such natural extracts.ResultsEthyl acetate extract deterred feeding of larvae better than other extracts with the concentrations causing 50% feeding inhibition (FI50) of 26.25 µg/cm2 and feeding deterrence index (FDI) of 91.8%, which was slightly lower than the positive control (cypermethrin, FDI = 100%; FI50 0.027 µg/cm2). The most effective feeding deterrent compounds against S. exigua were pinostrobin and pinocembrin with FDI range of 77 to 90% and FI50 values of 14.39 and 19.38 µg/cm2. In the greenhouse, the larvae treated on potted B. oleracea at FI50 concentrations (determined in laboratory experiments), ethyl acetate extract gave the highest mortality of 63.33% within 24 h of first spray and total of 73.33% after 24 h of the second spray. Impact on detoxification enzymes (24 h post-treatment) was determined from survived 3rd instars of S. exigua using spray applications. Inhibition of carboxylesterase (CE) was 1.94-fold after hexane extract treatment. However, ethyl acetate extract inhibited glutathione-s-transferase (GST) 1.30-fold.ConclusionsEthyl acetate extract of P. ribesioides twigs and isolated pinostrobin and pinocembrin compounds were potential antifeedants against S. exigua larvae. The data obtained also showed that such antifeedant levels of treatment could be used in greenhouse or field trials directly as an extract after establishing the efficacy of extracts and the active compounds therein under laboratory conditions.Graphical

Semiochemical tracks of predaceous Coccinellidae (Coleoptera) modulate feeding attributes and assimilation of nutrients in Zygogramma bicolorata (Coleoptera: Chrysomelidae)

AbstractParthenium hysterophorus Linnaeus (Asteraceae) is a toxic weed found abundantly in major agroecosystems of the world. The weed is inhabited by both phytophagous Chrysomelidae (Coleoptera), used as biocontrol agents, and the predaceous Coccinellidae (Coleoptera). The present investigation was designed to assess the feeding attributes and larval development of Zygogramma bicolorata Pallister (Coleoptera: Chrysomelidae) in the presence of semiochemical tracks of coccinellid beetles. Results revealed that the presence of coccinellid semiochemical tracks on the weed reduced larval consumption rates, conversion efficiencies, and growth rates. The feeding deterrent effects of the semiochemical tracks were species specific. Larvae accumulated lower concentrations of glucose, proteins, and triacylglycerols and exhibited reduced body biomass in the presence of semiochemical tracks. The coccinellid semiochemical tracks also promoted Z. bicolorata larvae to accelerate their developmental rates and develop faster than the larvae reared in the absence of semiochemical tracks. While the fourth instars consumed food maximally and were heavier, their food use efficiencies were lower than the other instars. Our findings, therefore, suggest that the presence of semiochemical tracks of coccinellids on P. hysterophorus impedes its biological control by Z. bicolorata larvae.

Chemical characterization and insecticidal effect against Sitophilus zeamais (maize weevil) of essential oil from Croton rudolphianus leaves

The control of insect pests (such as Sitophilus zeamais) depends mostly on the utilization of synthetic pesticides. Nevertheless, the application of these pesticides leads to many problems; environmental contamination, development of insect resistance, and adverse effects on human health are some of them. This study investigated the chemical constitution, insecticidal activity, and feeding deterrent and repellent effects on S. zeamais of essential oil (EO) obtained from Croton rudolphianus leaves. Fifty-four compounds were revealed in the C. rudolphianus oil. The major compounds of the oil consisted of an unknown compound (40.90%), methyl chavicol (22.96%), (E)-caryophyllene (4.22%), eugenol (4.03%), bicycloelemene (3.96%), bicyclogermacrene (3.81%), and spathulenol (2.79%). The EO was toxic to S. zeamais when ingested (LC50 102.66 μL/g) and caused changes in the nutritional parameters (relative consumption rate, relative biomass gain, and efficiency of food conversion). The oil was also toxic by contact (LC50 70.64 μL/mL) and fumigation [64 μL/L in the air caused the highest mortality (43.75%)]. However, no repellent property was detected. The results of this study showed that EO from C. rudolphianus leaves is toxic in different ways to S. zeamais adults, pointing to its potential use for grain protection.

Prey contaminated with neonicotinoids induces feeding deterrent behavior of a common farmland spider

Neonicotinoids are thought to have negligible repellent or anti-feeding effects. Based on our preliminary observations, we hypothesized that the contamination of spider prey with commonly used neonicotinoids has repellent or feeding deterrent effects on spiders. We tested this hypothesis by providing prey treated or not with field-realistic concentrations of neonicotinoids to the spiders and determining the number of (a) killed only and (b) killed and eaten prey. We exposed adult freshly molted and starved Pardosa agrestis, a common agrobiont lycosid species, to flies treated with neonicotinoids (acetamiprid, imidacloprid, thiacloprid and thiamethoxam) at field-realistic concentrations or with distilled water as a control. There were no effects of the exposure of the prey to neonicotinoids on the number of flies captured. However, the spiders consumed less of the prey treated with neonicotinoids compared to the ratio of control prey consumed, which resulted in increased overkilling (i.e., killing without feeding). In female P. agrestis, the overkilling increased from only 2.6% of control flies to 25–45% of neonicotinoid-treated flies. As the spiders avoided consuming the already captured neonicotinoid-treated prey, the sublethal effects of neonicotinoids extend beyond the simple attractivity/deterrence of the prey itself. The present study demonstrated that prey overkilling serves as a physiological response of spiders to the contact with the prey contaminated with agrochemicals. We speculate that primary contact with neonicotinoids during prey capture may play a role in this unexpected behavior.

The defensive function of a pollinator‐attracting floral volatile

AbstractBenzyl acetone (4‐phenylbutan‐2‐one; BA), the dominant floral fragrance of the wild tobaccoNicotiana attenuata, is known to attract night‐time pollinators, such asManduca sextahawkmoths. For this pollinator, BA is not only essential for the pollen transport between conspecific plants, but also for the moth’s short‐distance handling of flowers at night. The emission of BA from the corolla limb, however, starts up to 4 hr before dusk, peaks at dusk and continues throughout the first half of the night. While the function of the nocturnal part of the emission is well studied, the function of the early part of the peak emission remained unknown.By using plants silenced in the expression of the biosynthetic gene of BA (Nachal1), we investigated the function of this early peak emission of BA in the plants´ native habitat in Southwestern Utah.By emitting BA before dusk,N. attenuatais able to prevent the establishment and resulting floral damage by a florivore, the cucumber beetle (Diabrotica undecimpunctata). Plants lacking BA emissions (CHAL) were not only more often colonized by florivores, but also suffered significantly more damage, than control empty vector plants (EV). Choice assays revealed thatD. undecimpunctatafeeding required the absence of BA. While feeding damage to CHAL flowers was higher than to EV flowers in the early night hours, the effect disappeared during the second half of the night, when flowers stop emitting BA. The close proximity of BA‐emitting flowers to non‐emitting CHAL flowers preventedD. undecimpunctatafeeding. In the field, the emission of BA at dusk was sufficient to protect plants for the entire night, as beetles search for new hosts during the early evening hours and remain for the duration of the night, once a host is chosen.Floral BA emission before dusk may have evolved as a consequence of antagonistic interactions with florivores. A single floral volatile can thus simultaneously function as an important floral attractant for pollinators and as effective feeding deterrent against florivores in the same plant species.Aplain language summaryis available for this article.

Defence behind the ramparts: Spicule armament against specialist predators in a subtidal habitat-forming ascidian

Sessile organisms are reliant on the use of refugia or chemical and physical defences to avoid or reduce attacks from predators. Many solitary ascidians possess a thick leathery outer tunic, sometimes reinforced with inorganic inclusions, that generally acts to deter predators. The genus Herdmania is remarkable among ascidians in possessing an abundance of barbed needle-like calcareous spicules in both the external tunic and the internal mantle. Our focus was on a habitat-forming subtidal ascidian – Herdmania grandis. We questioned why a large ascidian possessing a leathery test would possess spicules within the mantle – an apparent defence within a defence. We first quantified variation in spicule size and density within animals. Second, we examined the size and density of spicules for individuals of a range of sizes. Third, we incorporated these spicules at natural concentrations into feeding discs and tested their ability to deter gastropod predators that specialise in consuming ascidians and an asteroid that is considered a generalist consumer. Finally, we examined survivorship of lab-reared ascidian recruits when exposed to the starfish predator. Spicules constituted up to 30% dry weight (DW) of the tunic and an astounding 57% DW of the body wall (mantle). Spicules were significantly smaller in the contractile regions of the animal (the siphon and branchial basket) and were also found in lower densities, though not significantly. Mantle spicules were effective feeding deterrents; control feeding discs, lacking spicules, were consumed at three times the rate of discs with spicules (p < 0.05) by specialist ascidian predators, the Ranellid gastropods Cabestana spengleri and Ranella australasia. In contrast, we did not detect a significant difference in the consumption of feeding discs by the seastar Meridiastra calcar. In addition, the seastar reduced survivorship of 90 day old lab-reared recruits by four-fold. We contend that the primary defence mechanism of this ascidian is the leathery test and that this is effective against generalist consumers. The second line of defence – spicules in the mantle –is to thwart gastropod predators that bypass the tunic either by boring through it or by inserting their proboscis directly into soft tissues of their prey via the siphons. The presence of both a leathery tunic and spicules in H. grandis probably contributes to the dominance of this species on shallow subtidal reefs in southeastern Australia, where it is an important habitat-forming species. Our findings confirm the importance of considering a range of consumer strategies and life history stages in assessing potential control of engineering species by predation.

Effects of the Botanical Compound p-Anisaldehyde on Horn Fly (Diptera: Muscidae) Repellency, Mortality, and Reproduction.

The horn fly, Haematobia irritans irritans (L.) (Diptera: Muscidae), is an economically important obligate blood feeder that mainly attacks cattle in Europe, Asia, and North and South America. As horn fly resistance to conventional insecticides becomes more common, alternative control tactics, such as application of bioactive botanical natural products are being investigated. p-Anisaldehyde has been found in many plant species, and it has shown effects that include mortality, attractancy, and interference with host seeking. The series of bioassays we developed was effective for assessing a range of horn fly responses to chemicals and probably those of some other filth fly species. In our study, p-anisaldehyde was lethal to horn fly eggs at concentrations of 0.00001%, and possibly less. Mixed into cow manure, 5000-20,000 ppm p-anisaldehyde reduced horn fly larvae by 85.4%-100%. p-Anisaldehyde caused some immobilization of adult horn flies when exposed by direct contract with spray droplets and by fumigation. Mortality was 90%-100% in response to 5%-10% concentrations by 30 min, and LD50 and LD90 values are reported for five times from 30 min-4 h. Complete horn fly mortality was achieved by fumigation with 0.75% p-anisaldehyde by 3 h in an enclosed space, and we determined that fumigation was more (≈12.5-fold) lethal to adult horn flies than sprayed droplets. Although horn flies were not repelled by p-anisaldehyde in static air tube olfactometers, the compound completely deterred feeding from cotton pads soaked in bovine blood in response to concentrations of 0.6% and greater in ventilated containers. Although horn fly control is not likely to use fumigation methods, p-anisaldehyde might be useful for adult control using sprays and egg and larval control using feed-through techniques. Exposure to sublethal concentrations of p-anisaldehyde did not affect horn fly egg production and hatching. Aside from causing different responses in the same species of arthropod, p-anisaldehyde has a variety of effects on other arthropods. Research on this compound as a potentially multifaceted pest management tool has been sparse. This study, for example, is the first to demonstrate p-anisaldehyde's feeding deterrent and immobilization properties and effects on different life stages.

Insecticidal activity of a protein extracted from bulbs of Phycella australis Ravenna against the aphids Acyrthosiphon pisum Harris and Myzus persicae Sulzer

Aphids cause significant losses in many agricultural crops and in many cases cause repeated insecticide sprays, which increase the risk of resistance. Therefore, other alternatives are needed to control them. The toxic, anti-reproductive, and feeding deterrent effects of a mannose-binding lectin isolated from bulbs of Phycella australis Ravenna (Amaryllidaceae), named Phycella australis-agglutinin (PAA) was assayed on nymphs of the aphids Acyrthosiphon pisum Harris and Myzus persicae Sulzer fed with an artificial diet. After 72 h of PAA exposure, lethal concentration (LC50) values were 109 and 313 mu g mL(-1) for A. pisum and M. persicae, respectively, while LC90 values were 248 and 634 mu g mL(-1). Sub-lethal concentrations of PAA significantly reduced the aphid fecundity at a concentration of 80 mu g mL(-1). Only a total of 5.7 descendants per female were recorded for A. pisum (32% control progeny) and 12.4 for M. persicae (39% control progeny). Acyrthosiphon pisum was strongly deterred by PAA under choice conditions, as after 72 h exposed to 80 mu g PAA mL(-1) of diet, the feeding deterrent index was 0.91 for A. pisum and only 0.38 for M. persicae. In conclusion, the mannosebinding lectin isolated from bulbs of P. australis showed acute and chronical insecticidal activity against the pea and green peach aphids.

Feeding Deterrent and Genotoxicity Analysis of a novel Phytopesticide by using Comet Assay against Helicoverpa armigera (HÜbner) (Lepidoptera: Noctuidae)

Newly developed Phytopesticidal formulations from pongam and neem oils were evaluated for their feeding deterrent activity using leaf disc choice and no-choice methods, and genotoxic study using comet assay against Helicoverpa armigera at different concentrations of 5, 10, 15, and 20 ppm. Among various phytopesticidal formulations, neem and pongam oils at 1:1 ratio, called PONNEEM showed significant feeding deterrent activity against H. armigera at 20 ppm concentration and wasgenotoxic to H. armigera (P>0.001). The comet parameters, namely tail moment (arbitrary units), tail length (µm) and tail DNA (%) were observed at all the concentrations of PONNEEM. Statistically significant changes in all the comet parameters of H. armigera were observed at 20 ppm (P<0.001). Feeding deterrent and genotoxicity effect of PONNEEM could be applied as phytopesticide for controlling the lepidopteran insect pests.

Evaluation of the toxicity of essential oil from Alpinia purpurata inflorescences to Sitophilus zeamais (maize weevil)

The maize weevil, Sitophilus zeamais Motsch. (Coleoptera: Curculionidae), is a cosmopolitan pest that causes extensive and irrecoverable damage to storage grains. This work investigated the chemical composition, insecticidal activity, feeding-deterrent and repellent effects of an essential oil from Alpinia purpurata inflorescences against S. zeamais. Analysis by gas chromatography coupled to mass spectrometry (GC–MS) revealed the presence of 30 volatile constituents (mainly mono- and sesqui-terpenes). The main compounds found in the oil were β-pinene, α-pinene, trans-caryophyllene, camphene, and 7-epi-α-selinene. When ingested by S. zeamais adults, the A. purpurata oil did not kill the insects but disrupted their nutritional status since biomass gain rate and efficiency in conversion of ingested food were both negative or near zero. A weak feeding-deterrent effect was also detected. No toxicity was observed when the oil was applied directly on the cuticle of S. zeamais adults. The fumigant toxicity assay revealed that the A. purpurata oil killed S. zeamais adults with LC50 = 41.4 μL/L in air; however, no repellent property was detected. The essential oil from A. purpurata inflorescences was toxic to S. zeamais adults by fumigation and due to interferences in digestion of food. Fumigant toxicity is likely due to the presence of some monoterpene hydrocarbons and oxygenated monoterpenes.

Repellent Effects of Annona Crude Seed Extract on the Asian Subterranean Termite Coptotermes gestroi Wasmann (Isoptera:Rhinotermitidae)

Crude seed extract of three tropical fruits belonging to the family Annonaceae, viz., sweetsop ( Annona squamosa L.), soursop ( A. muricata L.) and biriba ( Rollinia mucosa Baill.) were investigated for their repellent effects on the Asian subterranean termite Coptotermes gestroi Wasmann (Isoptera: Rhinotermitidae ). Results of laboratory feeding bioassay (choice and no-choice) indicated that crude extract of A. squamosa, A. muricata and R. mucosa had feeding deterrent effects on C. gestroi . Termites showed significant avoidance behavior to filter paper treated with extracts of the three Annona species investigated. Soil barrier test revealed that Annona extracts were able to limit penetration of C. gestroi in laboratory tunneling test. The results suggest that Annona seed extracts may offer an alternative source of natural insecticide against subterranean termites.