Control Insects Research Articles

A Review of Bioinsecticidal Activity and Mode of Action of Plant

Plants contain many bioactive compounds as a means of defense against insects. Some plants produce toxic compounds that could affect or kill the insect completely. These natural compounds are an alternate for synthetic insecticides that cause many problems to the environment and human health. Hence, there is an urgent need for botanical insecticide which is eco-friendly and control insects in short duration. The secondary metabolites namely alkaloids have significant effects on insects. The alkaloids can affect insects through biological action such as disturbing the cellular and physiological process via redox imbalance and hormonal regulation. In this review, we present data on sub lethal and lethal toxicity caused by the various species and alkaloids obtained from the plants. The pure alkaloids and extracts of various plants cause toxicity towards insects which are considered as the important point of view economically.

Активность ферментов детоксикации у имаго комнатной мухи Musca domestica L. при селекции хлорфенапиром

In insects, biochemical mechanisms of insecticide resistance base on increasing of activities of main detoxyfying enzymes – monooxygenases, nonspesific esterases, and glutathion-S-transferases. Currently, the progress of resistance development and the degree of contributing enzymes to resistance in insects have been studied for certain insecticides. The goal of this study was to assess activities of monooxygenase, carboxylesterase, glutathione-S-transferase, and alkaline phosphatase in females and males housefly Musca domestica in the second, fourth, sixth, eighth and tenth generations of the chlorfenapyr-selected strain. Evaluation of chlorfenapyr susceptibility showed that adults M. domestica in tenth generations was tolerating to chlorfenapyr as the resistance ration value was 3.6. In certain generations of chlorfenapyr-selected strain M. domestica, monooxygenase activities in males and females were 1.4-2.1 times more, and alkaline phosphatase activities in females were 2.3-2.7 times more than that in control insects. Glutathione-S-transferase activities had no significant differences in adults M. domestica of control and chlorfenapyr-selected strains. For chlorfenapyr-selected strain M. domestica, activities of monooxygenase, carboxylesterase, and alkaline phosphatase differed in males and females of same generations that suggests that mode and pattern of resistance development might be sex-specific in this specie.

Herbal syrup from chicory and artichoke leaves ameliorate liver damage induced by deltamethrin in weanling male rats.

Pyrethroid insecticides are extensively used for control insects in both public health and agriculture sectors. Despite the important role of these insecticides, it caused adverse toxic effects on human, especially at the weanling stage. In this work, the antioxidant activity of chicory and artichoke leaves extracts, and phenolic flavonoid contents were studied. In addition, herbal syrup formulation and hepatoprotective effect against oxidative stress, lipid peroxidation, and liver damage induced by deltamethrin in weanling male rats were investigated. Both extracts have high phenolic, flavonoid contents, and antioxidant activity. Deltamethrin reduced body and liver weights of weanling rats. It induced oxidative stress, lipid peroxidation, and altered liver function enzymes. It caused a histopathological alteration in liver tissue. Supplementation of herbal syrup improved the above changes via increase body weights, antioxidant enzymes, and decrease lipid peroxidation, and enhanced histopathological profile. It can be concluded that herbal syrup of chicory and artichoke leaves extracts can ameliorate liver damage induced by deltamethrin. Herbal syrup from agriculture wastes of chicory and artichoke leaves is considered an easy, economical, and useful formulation for protecting agriculture workers against the adverse effects induced by pyrethroid insecticides especially in poor rural in developing countries where pyrethroid insecticides are applied for control vector-borne diseases and insects in agriculture.

Bioaccumulation of Cadmium Affects Development, Mating Behavior, and Fecundity in the Asian Corn Borer, Ostrinia furnacalis.

Heavy metal pollution is becoming an increasingly serious problem in agricultural ecosystems. Heavy metals such as cadmium (Cd) accumulate in the food chain and may lead to detrimental effects on the physiological functions of living organisms, including herbivorous insects. One such example is the Asian Corn Borer, Ostrinia furnacalis (Lepidoptera: Pyralidae). However, how Cd can affect the development and reproduction of O. furnacalis is largely unknown. In this study, we exposed larvae of O. furnacalis to a diet containing Cd and investigated the effects of Cd on the development, mating behavior, and fecundity of the insect. We showed that Cd accumulates in the larvae and inhibits development by extending larval and pupal duration and decreasing the survival rate. The excretion of Cd through multiple routes during the larval and pupal stages resulted in low levels of residual Cd in the adult insects, which were not fed with Cd. However, the mating behavior and fecundity of these insects were significantly affected, compared to control insects. This suggests that the bioaccumulation of heavy metals such as Cd has long lasting and detrimental effects on O. furnacalis over the entire life cycle, affecting fecundity, even when specimens are only exposed at an early life stage.

Induction of DNA methyltransferase genes in Helicoverpa armigera following injection of pathogenic bacteria modulates expression of antimicrobial peptides and affects bacterial proliferation

Following pathogen attack in a host, widespread changes are induced in the host’s gene expression, in particular those involved in the immune system, growth and survival. Epigenetic mechanisms have been suggested to be involved in the regulation of these changes through a number of mechanisms. DNA methylation is one of the important epigenetic processes that is carried out by DNA (cytosine-5) methyltransferase (DNMT) and alters expression of target genes. Here, we identified two putative sequences of DNMT (i.e. DNMT1 and DNMT2) from the transcriptome dataset of Helicoverpa armigera that showed high similarity to the homologous sequences in Bombyx mori. Domain architectures of DNMT1 and DNMT2 exhibit the unique pattern of DNMTs that highlights conserved function of these genes in different insects. To see if these genes play any role in bacterial infection, we challenged the fifth instar larvae of H. armigera by injecting Bacillus thuringiensis and Serratia marcescens cells into the hemolymph. Transcript levels of the DNMTs were analyzed by RT-qPCR. The results showed that the expression levels of DNMT1 and DNMT2 increased in the bacteria-injected larvae. Injection of the heat-killed bacteria also induced the expression of the DNMTs, but lower than that of the live bacteria. To determine whether these genes function during bacterial infection, we injected the inhibitor of DNMTs, 5-azacytidine (5-AZA), into the larvae and 24 h later, the bacterial cells were also injected into the larvae. Bacterial replication and larval mortality were analyzed in the treated and control insects. We found that 5-AZA reduced bacterial replication and also mortality of the bacterial-injected larvae regardless of the pathogenic bacterial species. Interestingly, the expression levels of antimicrobial peptides (AMPs) were also modulated following 5-AZA treatment. In conclusion, we showed that upregulation of the DNMTs in H. armigera following bacterial infections modulates AMPs and thereby affects the insect-bacteria interactions.

Transcriptome and proteome analyses to investigate the molecular underpinnings of cold response in the Colorado potato beetle, Leptinotarsa decemlineata

The Colorado potato beetle (Leptinotarsa decemlineata (Say)) is an insect that can cope with prolonged periods of low temperatures exposure. The molecular changes required to adapt to such conditions have not been thoroughly investigated in this insect. The current work aims at characterizing deregulated transcripts and proteins in adult L. decemlineata exposed to 15 °C and −5 °C using RNA-sequencing-based transcriptomics and liquid chromatography tandem mass spectrometry (LC-MS/MS)-based proteomics approaches, respectively. RNA-sequencing highlighted the differential expression of several transcripts, including ubiquilin-1 and ubiquitin carboxyl-terminal hydrolase 5, in insects submitted to low temperatures when compared with control insects. In addition, proteomics approach detected 2840 proteins in cold-exposed beetles including elevated levels for 409 proteins and reduced levels for 200 proteins. Cuticular proteins CP1, CP4, CP5 and CP7 as well as eukaryotic translation initiation factor 4B were notable proteins with elevated levels in cold insects. Functional analysis of targets modulated at low temperatures using DAVID indicated processes likely affected under cold conditions including select metabolic cascades and RNA-associated processes. Overall, this work presents molecular candidates impacted by low temperatures exposure in L. decemlineata and builds on the current knowledge associated with response to these conditions in this insect.

Comparative Assessment of Certain Insecticidal Compounds on the Development and Adult Performance of Red Palm Weevil, Rhynchophorus ferrugineus Olivier (Coleoptera: Curculionidae).

The red palm weevil Rhynchophorus ferrugineus is a serious pest of date palm in different regions of the Middle East. The present study was carried out to evaluate comparatively the effects of pyriproxyfen (insect growth regulator), neemazal (a plant product) and spinetoram (a bacterial product) on growth, development and adult performance of this insect pest. The early 5th instar larvae were treated with five sublethal concentrations of each compound. The most important results can be summarized as follows. Both larval duration and weight were considerably reduced by Spinetoram. Pyriproxyfen significantly reduced the larval duration only at 4000 ppm (7.2±2.97, compared to 11.7±1.6 days control insects) but Neemazal could not exhibit a remarkable effect. The strongest reducing effect on larval weight was recorded for Pyriproxyfen, since the growth inhibition% was determined as 49.10, 48.58 and 38.04, at 4000, 2000 and 1000 ppm, respectively. Pupation was inhibited by all tested insecticidal compounds and the pupal duration was significantly shortened, except at the lower three concentrations of Neemazal. Some deformations had been recorded only in adults, irrespective of the tested compound. The adult longevity was significantly shortened at the higher concentrations of each compound.

RNA sequencing, selection of reference genes and demonstration of feeding RNAi in Thrips tabaci (Lind.) (Thysanoptera: Thripidae)

BackgroundThrips tabaci is a severe pest of onion and cotton. Due to lack of information on its genome or transcriptome, not much is known about this insect at the molecular level. To initiate molecular studies in this insect, RNA was sequenced; de novo transcriptome assembly and analysis were performed. The RNAseq data was used to identify reference and RNAi pathway genes in this insect. Additionally, feeding RNAi was demonstrated in T. tabaci for the first time.ResultsFrom the assembled transcriptome, 27,836 coding sequence (CDS) with an average size of 1236 bp per CDS were identified. About 85.4% of CDS identified showed positive Blast hits. The homologs of most of the core RNAi machinery genes were identified in this transcriptome. To select reference genes for reverse-transcriptase real-time quantitative PCR (RT-qPCR) experiments, 14 housekeeping genes were identified in the transcriptome and their expression was analyzed by (RT-qPCR). UbiCE in adult, 28s in nymphs and SOD under starvation stress were identified as the most stable reference genes for RT-qPCR. Feeding dsSNF7 and dsAQP caused 16.4- and 14.47-fold reduction in SNF7 and AQP mRNA levels respectively, when compared to their levels in dsGFP fed control insects. Feeding dsSNF7 or dsAQP also caused 62 and 72% mortality in T. tabaci. Interestingly, simultaneous feeding of dsRNAs targeting SNF7 or AQP and one of the RNAi pathway genes (Dicer-2/Aubergine/Staufen) resulted in a significant reduction in RNAi of target genes. These data suggest the existence of robust RNAi machinery in T. tabaci.ConclusionThe current research is the first report of the assembled, analyzed and annotated RNAseq resource for T. tabaci, which may be used for future molecular studies in this insect. Reference genes validated across stages and starvation stress provides first-hand information on stable genes in T. tabaci. The information on RNAi machinery genes and significant knockdown of the target gene through dsRNA feeding in synthetic diet confirms the presence of efficient RNAi in this insect. These data provide a solid foundation for further research on developing RNAi as a method to manage this pest.

Effects of FABP knockdown on flight performance of the desert locust, Schistocerca gregaria.

During migratory flight, desert locusts rely on fatty acids as their predominant source of energy. Lipids mobilized in the fat body are transported to the flight muscles and enter the muscle cells as free fatty acids. It has been postulated that muscle fatty acid binding protein (FABP) is needed for the efficient translocation of fatty acids through the aqueous cytosol towards mitochondrial β-oxidation. To assess whether FABP is required for this process, dsRNA was injected into freshly emerged adult males to knock down the expression of FABP. Three weeks after injection, FABP and its mRNA were undetectable in flight muscle, indicating efficient silencing of FABP expression. At rest, control and treated animals exhibited no morphological or behavioral differences. In tethered flight experiments, both control and treated insects were able to fly continually in the initial, carbohydrate-fueled phase of flight, and in both groups, lipids were mobilized and released into the hemolymph. Flight periods exceeding 30min, however, when fatty acids become the main energy source, were rarely possible for FABP-depleted animals, while control insects continued to fly for more than 2 h. These results demonstrate that FABP is an essential element of skeletal muscle energy metabolism in vivo.

RNA interference of muscle actin and ATP synthase beta increases mortality of the phytoplasma vector Euscelidius variegatus.

RNA interference (RNAi) techniques have emerged as powerful tools to develop novel management strategies for the control of insect pests. The leafhopper Euscelidius variegatus is a natural vector of chrysanthemum yellows phytoplasma and a laboratory vector of Flavescence dorée phytoplasma. Phytoplasmas are insect-borne bacterial plant pathogens that cause economically relevant crop losses worldwide. In this study, we demonstrated that microinjection of muscle actin and ATP synthase β double-stranded (ds)RNAs into adult insects caused an exponential reduction in the expression of both genes, which began within 72 h of dsRNA administration and lasted for 14 days, leading to almost complete silencing of the target genes. Such silencing effects on muscle actin expression appeared to be both time- and dose-dependent. Our results also showed that the knockdown of both genes caused a significant decrease in survival rates in comparison with green fluorescent protein (GFP) dsRNA-injected control insects. The effectiveness of RNAi-based gene silencing in E. variegatus guarantees the availability of a powerful reverse genetic tool for the functional annotation of its genes and the identification of those potentially involved in the interaction with phytoplasmas. In addition, this study demonstrated that muscle actin and ATP synthase β may represent candidate genes for RNAi-based control of E. variegatus. © 2018 Society of Chemical Industry.

Upregulation of Helicoverpa armigera core RNA interference genes by bacterial infections and its effect on the insect–bacteria interaction

RNA interference (RNAi) is an extremely conserved defence mechanism. The antiviral role of the RNAi pathway in insects is well documented; however, the relevance of this pathway in other aspects of insect immunity is largely unknown. In this study, we questioned whether RNAi has any function during insect-bacteria interactions. For this, we assessed induction of the RNAi pathway in response to bacterial infections by monitoring the expression of dicer1/argonaute1 and dicer2/argonaute2, which are important genes in the microRNA and short interfering RNA sub-pathways respectively. Bacterial cells of Bacillus thuringiensis and Serratia marcescens were injected into the haemocoel of fifth-instar larvae of Helicoverpa armigera, whereas double-distilled water was injected into control insects. Expression levels of the RNAi-related genes increased in the bacteria-injected larvae compared with controls. Transcript knockdown of dicer1 reduced the replication of B.thuringiensis; as a consequence, larval mortality decreased compared with the control. However, replication of S.marcescens increased following dicer1 silencing, which led to higher rates of larval mortality when compared with the control. RNAi of dicer2 promoted replication of both bacteria in the larvae and also enhanced larval mortality. Therefore, dicer1 and dicer2 affected larval survival and the replication rates of the pathogenic bacteria, suggesting their roles in the interactions.

Fogging loads of California fresh citrus for control of Asian citrus psyllid, Diaphorina citri :

Contact insecticides are commonly applied as fogs to disinfest and disinfect spaces. Recently, these fogs have been adapted to treat commodity within the spaces, and much has been learned regarding the efficacy of this process. When considering fresh citrus in California, fogs are applied to control both insects and microbes. One insect pest, the Asian citrus psyllid (ACP), Diaphorina citri, is a quarantine pest in California and limiting its geographic distribution is a major goal of the California citrus industry. While a variety of phytosanitary measures can be used to control adult ACP once fruit is at a packing house, ultimately, a treatment must be developed to disinfest field-run fruit prior to its exiting the grove. High-pressure fogging with 1,100-L of an aqueous mixture containing 0.2% Evergreen® (6% pyrethrins & 60% piperonyl butoxide) and 0.5% (v/v) BreakThru® (polysiloxane surfactant) was explored in laboratory-, pilot-, and commercial-scale trials as an approach to disinfest a 48-bin trailer load of fresh citrus. Laboratory-scale studies were conducted to quantify, and subsequently model, insecticidal coverage as a function of temperature, surface area, droplet size, and fog volume. Results are discussed in the context of experimental variability across confirmatory trials and continued efforts to optimize the technical and economic feasibility of fogging as a postharvest control strategy.

Innovative stored plant products in Germany and the potential threat by native and invasive pest insects: Presentation

Climate change, economic-political developments as well as new trends in diet and in bio-economy considerably influence the assortment of cultivated plants in Germany and thereby, determine the plant products which have to be stored after harvest. In the light of the International Year of Pulses 2016 and also, as a result of the European Soya Declaration, the acreage cultivated with new plants such as pulses, stress tolerant wheat varieties and also oil seed rape expanded worldwide. Due to increasing stocks of novel commodities, the emergence of economically important insects infesting stored products and the possible risk caused by native and invasive pest species have to be generally considered during storage. In this overall context, we studied the capacity of various stored-product pest insects to infest two important pulses. In laboratory tests different varieties of soy and lupine have been offered as whole seeds, grist and flour to selected moth and beetle species common in Germany. Over 14 weeks we examined the developmental time from egg to eclosion as well as the number of adults in the F1 generation compared to control insects reared on their standard feeding substrate. First findings under laboratory conditions (20-25 °C, 65-70 % RH) indicate that these innovative stored products, and in particular its simply processed plant products are highly susceptible to moths (i.a. Ephestia elutella, Plodia interpunctella) and to a much lesser extent also to some beetle species (i.a. Callosobruchus chinensis, Tribolium confusum), but the usally recommended optimal storage conditions (T = 16 °C, RH = 65%) can prevent a loss of volume and quality.

Effects of DEHP on post-embryonic development, nuclear receptor expression, metabolite and ecdysteroid concentrations of the moth Spodoptera littoralis

Di (2-ethylhexyl) phthalate (DEHP) is recognized in vertebrates as an Endocrine Disrupting Chemical (EDC). DEHP can alter steroid hormones production, development, reproduction and behavior in vertebrates. Only few studies investigated DEHP effects on insects. However, some recent studies on aquatic insects showed that DEHP could also act as an EDC by interfering with the signaling pathways of ecdysteroids, the main hormones involved in the control of insect post-embryonic development and physiology. The aim of the study was to investigate (1) the fate of DEHP within a terrestrial insect species by exposing larvae to food containing a wide range of DEHP concentrations and (2) the effects of this chemical on their post-embryonic development and metamorphosis, by using a multi-level approach. DEHP was shown to be present both in larvae and resulting stages, with higher concentrations in chrysalises and adults than in larvae. DEHP concentrations also decreased at the end of the last larval instar, suggesting the metabolic transformation or excretion of this chemical during this time. Only the two highest DEHP doses induced higher insect mortality, whereas low and intermediate concentrations increased larval food consumption without affecting body weight. Metabolic profiles showed that in control insects, the last three days before metamorphosis correspond to a metabolic transition, but with time-dependent changes in treated insects. Interestingly, DEHP treatments also alter both hemolymphatic ecdysteroid titers and expression levels of ecdysteroid response genes. These results confirm that DEHP can alter insect post-embryonic development and metamorphosis, by interfering with ecdysteroid pathways.

Insecticidal effects of the Olea europaea subsp. laperrinei extracts on the flour Pyralid Ephestia kuehniella

In the present study, the aerial parts of the Laperrine olive (Olea europaea subsp. Laperrinei) are subjected to acid extraction and the chemical composition of the extracts is determined by HPLC-DAD. The main compounds found in all of extracts are: hydroxytyrosol (30.45%), tyrosol (0.69%), oleuropein (32.76%), ferrulic acid (17.77%), quercetin (31.57%) and hesperetin (6.90%).The extracts obtained from the leafy stems of Laperrine olive tree are tested on the moth Ephestia kuehniella flour. Their administration by inhalation of newly exuviated chrysalises extends the duration of nymphalid development and disturbs the exuviated adults reproduction, by reducing the period in which the eggs are being laid. Thus, compared to the control insects, the number of eggs laid by treated females is significantly reduced after the treatment by extracts. Besides, the administration of different extracts of adult butterflies has a premature mortality effect.

Cellulose degradation in Gastrophysa viridula (Coleoptera: Chrysomelidae): functional characterization of two CAZymes belonging to glycoside hydrolase family 45 reveals a novel enzymatic activity.

Cellulose is a major component of the primary and secondary cell walls in plants. Cellulose is considered to be the most abundant biopolymer on Earth and represents a large potential source of metabolic energy. Yet, cellulose degradation is rare and mostly restricted to cellulolytic microorganisms. Recently, various metazoans, including leaf beetles, have been found to encode their own cellulases, giving them the ability to degrade cellulose independently of cellulolytic symbionts. Here, we analyzed the cellulosic capacity of the leaf beetle Gastrophysa viridula, which typically feeds on Rumex plants. We identified three putative cellulases member of two glycoside hydrolase (GH) families, namely GH45 and GH9. Using heterologous expression and functional assays, we demonstrated that both GH45 proteins are active enzymes, in contrast to the GH9 protein. One GH45 protein acted on amorphous cellulose as an endo-β-1,4-glucanase, whereas the other evolved to become an endo-β-1,4-xyloglucanase. We successfully knocked down the expression of both GH45 genes using RNAi, but no changes in weight gain or mortality were observed compared to control insects. Our data indicated that the breakdown of these polysaccharides in G. viridula may facilitate access to plant cell content, which is rich in nitrogen and simple sugars.

Coinfection of the secondary symbionts, Hamiltonella defensa and Arsenophonus sp. contribute to the performance of the major aphid pest, Aphis gossypii (Hemiptera: Aphididae).

Bacterial endosymbionts play important roles in ecological traits of aphids. In this study, we characterize the bacterial endosymbionts of A. gossypii collected in Karaj, Iran and their role in the performance of the aphid. Our results indicated that beside Buchnera aphidicola, A. gossypii, also harbors both Hamiltonella defensa and Arsenophonus sp. Quantitative PCR (qPCR) results revealed that the populations of the endosymbionts increased throughout nymphal development up to adult emergence; thereafter, populations of Buchnera and Arsenophonus were diminished while the density of H. defensa constantly increased. Buchnera reduction caused prolonged development and no progeny production. Furthermore, secondary symbiont reduction led to reduction of the total life span and intrinsic rate of natural increase as well as appearance of the deformed dead offspring in comparison with the control insects. Reduction of the secondary symbionts did not affect parasitism rate of the aphid by the parasitic wasp Aphidius matricariae. Together these findings showed that H. defensa and Arsenophonus contributed to the fitness of A. gossypii by enhancing its performance, but not through parasitoid resistance.

Identification of differentially expressed proteins in Ostrinia furnacalis adults after exposure to ultraviolet A

Ultraviolet A (UVA), the major component of solar UV irradiation, is an important environmental factor inducing damage to insects including cell death, photoreceptor damage, and oxidative stress. In order to improve understanding of the adaptation mechanisms of insect after UVA exposure, a comparative proteomic analysis was carried out to reveal differential protein expression in Ostrinia furnacalis. Three-day-old adults were treated with UVA for 1h. Total proteins of control and UVA-treated insects were examined using two-dimensional electrophoresis (2-DE). 2-DE analysis demonstrated that 19 proteins were increased and 18 proteins were decreased significantly in O. furnacalis after UVA exposure, respectively. Thirty differentially expressed proteins were successfully identified by mass spectrometry. The identified proteins were involved in diverse biological processes, such as signal transduction, transport processing, cellular stress, metabolisms, and cytoskeleton organization. Our results reveal that the response patterns of O. furnacalis to UVA irradiation are complex and provide novel insights into the adaptation response to UVA irradiation stress.

Characterization of a β-N-acetylglucosaminidase gene and its involvement in the development of Lasioderma serricorne (Fabricius)

β-N-acetylglucosaminidases (NAGs) are essential enzymes in the chitin degradation process and play important roles in insect molting and metamorphosis. In this study, we identified and characterized a full-length cDNA of NAG1 (LsNAG1) in the cigarette beetle, Lasioderma serricorne (Fabricius). The open reading frame of LsNAG1 was 1821 bp and encoded 606 amino acid residues that contained typical domain structure of NAGs. Phylogenetic analyses suggested that the deduced protein LsNAG1 was orthologous to another insect group I NAGs. Quantitative real-time PCR confirmed that LsNAG1 expression levels peaked periodically in the late larval and late pupal stages. A significantly increased level of LsNAG1 transcripts was observed in larvae exposed to the steroid hormone 20-hydroxyecdysone (20E), indicating LsNAG1 was responsive to 20E. Injection of double-stranded RNA (dsRNA) of LsNAG1 into 4th instar larvae and late pupae significantly reduced LsNAG1 transcript levels in both stages, and led to severe molting defects and high mortality. Compared with the control insects injected with dsGFP, 48% and 83% of the larvae and pupae injected with dsLsNAG1, respectively, died during or soon after molting to the next stage. These results demonstrate that LsNAG1 may play a crucial role in successful larval–pupal and pupal–adult transitions, and could be used as an efficient novel target for storage pest control.

Particulate matter on two Prunus spp. decreases survival and performance of the folivorous beetle Gonioctena quinquepunctata

Woody plants growing along streets and construction sites play an important role in removing harmful particulate matter (PM). Researchers rarely consider the impact of different types and size fractions of PM deposited on the leaves on insect folivores. We determined differences in the accumulation of cement and roadside PM on the leaves of two Prunus species (P. padus and P. serotina) with different leaf surface structures. We also determined the effect of PM on the beetle Gonioctena quinquepunctata, the main pest of these plants. Saplings were artificially dusted in greenhouses and leaves were utilised for larval and adult insect stages feeding in laboratory conditions. Road PM accumulated in greater amounts than did cement PM, regardless of plant species. For both PM sources, P. padus accumulated twofold more than did P. serotina. Insect survival was negatively affected by PM pollution; however, neither Prunus species nor PM source variant significantly affected masses of larvae and pupae, duration of larval and pupal development or relative growth rates. The experiment showed strong negative influences of PM were noted only for adult insects, due to the grazing period being longer than that in larvae. The mass of adult insects and the efficiency of conversion of ingested food (ECI) were lower for insects exposed to PM than those for control insects. Insects compensated for lower ECI by eating a greater total amount of food (TFE). Adult insects gained significantly higher mass when fed with P. serotina than with P. padus. The effect of PM on analysed plant metabolites was insignificant. Only Prunus sp. and date of collection affected the level of condensed tannins and total phenols. Our results indicate that, when investigating the effect of the host plant on folivore performance, the accumulation of PM, as well as its type and quantity, should be taken into account.