Exploring the bio-insecticidal activity of Eucalyptus globulus essential oil/ß-cyclodextrin inclusion complexes: In vitro and in silico assessment against Ephestia kuehniella larvae.

Owing to their beneficial functional capabilities, essential oils were largely used. However, their low aqueous solubility, instability, and high volatility urged scientists to their encapsulation with cyclodextrins (CDs) to tackle their shortcomings. In this study, the co-precipitation method was used to prepare ß-CD/Eucalyptus globulus essential oil (EGEO) inclusion complexes (ICs). ß-CD/EGEO ICs were prepared at ratios (w:w) 1:2 and 1:4 with an encapsulation efficiency of 93 and 96%, respectively. The ICs characterization using the Fourier transform Infrared spectroscopy, differential scanning calorimetry, X-ray powder diffraction, Dynamic Light Scattering, and Laser Doppler Velocimetry confirmed the formation of ß-CD/EGEO ICs. The insecticidal activity of the free EGEO and ICs was explored and displayed that the complex ß-CD/EGEO 1:4 had the highest activity with the lowest LC50 against Ephestia kuehniella larvae (5.03 ± 1.16 mg/g) when compared to the free oil (8.38 ± 1.95 mg/g). Molecular docking simulations stipulated that the compound α-Bisabolene epoxide had the best docking score (ΔG = -7.4 Kcal/mol) against the selected insecticidal target α-amylase. Additionally, toxicity evaluation of the studied essential oil suggested that it could be safely used as a potent bioinsecticide as compared to chemical insecticides. This study reveals that the formation of ß-CD/EGEO ICs enhanced the oil activity and stability and could be a promising and safe tool to boost its application in food or pharmaceutical fields.

Environmental impact assessment of dicationic ionic liquids with ammonium-phosphonium cations and amino acid anions.

Progress in the development of biodegradable or biobased ionic liquids (ILs) has led to the design of green compounds for several applications. Herein, four biocompatible dicationic ionic liquids (DILs) with ammonium-phosphonium cations and amino acid anions were synthesized and investigated their environmental impact. The structures of the DILs were confirmed by spectral analyses (1H, 13C and 31P NMR). Furthermore, physicochemical properties such as density, viscosity and refractive index were determined. Water content, bromide content and solubility were thereafter determined as the parameters needed for further studies. Subsequently, their antifeedant activity towards economically important pests of grain in storage warehouses: the granary weevil, the confused flour beetle, and the khapra beetle was examined, showing the dependence on structure. Moreover, selected DILs were investigated for toxicity towards white mustard, Daphnia magna, and Artemia franciscana to specify the environmental impact. These studies were complemented by understand the biodegradation of DILs by bacterial communities derived from soil at the agricultural land. The result was DILs with limited environmental footprints that have great potential for further application studies.

Assessment of Boll Weevil Susceptibility to Isocycloseram and Ethiprole and Differential Toxicity to Natural Enemies.

Insecticides efficient against the target species while conserving natural enemies in the agroecosystem are required for IPM. With the imminent discontinuation of fipronil, a broad-spectrum insecticide, ethiprole, which belongs to the same group as phenylpyrazole (2B), and isocycloseram, a novel isoxazoline insecticide with distinct mode of action (30), provide options for controlling boll weevil. The susceptibility of the boll weevil, Anthonomus grandis grandis (Boh.), and two natural enemies [Eriopis connexa (Germar) and Bracon vulgaris Ashmead] to these insecticides were studied. Furthermore, the survival and biological traits of the lady beetle, E. connexa, exposed to fipronil, isocycloseram, and ethiprole were assessed. The LC50s values for fipronil, ethiprole, and isocycloseram for A. grandis grandis were 2.71, 0.32, and 0.025 mg a.i./L, respectively; 0.86, > 200, and 3.21 mg a.i./L for E. connexa; and 2.31, 592.94, and 0.18 mg a.i./L for B. vulgaris, respectively. The recommended rates of ethiprole did not cause mortality in adult lady beetles, although fipronil and isocycloseram were highly toxic. Lady beetle larvae and adults survived more than 80% when exposed to dried residues of ethiprole, but less than 10% when exposed to fipronil and isocycloseram. Lady beetle larvae development, reproduction, and predation rates of adults were similar between ethiprole and the control group. Although fipronil and ethiprole belong to the same insecticide group, the difference in toxicity to boll weevils and natural enemies is presented and discussed. Ethiprole was more toxic to boll weevils than to its parasitoid and lady beetle, and isocycloseram was highly toxic to all three species.

Crop rotation mitigates impacts of corn rootworm resistance to transgenic Bt corn.

Transgenic crops that produce insecticidal proteins from Bacillus thuringiensis (Bt) can suppress pests and reduce insecticide sprays, but their efficacy is reduced when pests evolve resistance. Although farmers plant refuges of non-Bt host plants to delay pest resistance, this tactic has not been sufficient against the western corn rootworm, Diabrotica virgifera virgifera In the United States, some populations of this devastating pest have rapidly evolved practical resistance to Cry3 toxins and Cry34/35Ab, the only Bt toxins in commercially available corn that kill rootworms. Here, we analyzed data from 2011 to 2016 on Bt corn fields producing Cry3Bb alone that were severely damaged by this pest in 25 crop-reporting districts of Illinois, Iowa, and Minnesota. The annual mean frequency of these problem fields was 29 fields (range 7 to 70) per million acres of Cry3Bb corn in 2011 to 2013, with a cost of $163 to $227 per damaged acre. The frequency of problem fields declined by 92% in 2014 to 2016 relative to 2011 to 2013 and was negatively associated with rotation of corn with soybean. The effectiveness of corn rotation for mitigating Bt resistance problems did not differ significantly between crop-reporting districts with versus without prevalent rotation-resistant rootworm populations. In some analyses, the frequency of problem fields was positively associated with planting of Cry3 corn and negatively associated with planting of Bt corn producing both a Cry3 toxin and Cry34/35Ab. The results highlight the central role of crop rotation for mitigating impacts of D. v. virgifera resistance to Bt corn.

In silico identification and assessment of insecticide target sites in the genome of the small hive beetle, Aethina tumida.

BACKGROUND: The small hive beetle, Aethina tumida, is a rapidly emerging global pest of honey bee colonies. Small hive beetle infestation can be extremely destructive, which may cause honey bees to abscond and render colony infrastructure unusable. Due to the impacts small hive beetles have on honey bees, a wide variety of physical, cultural, and chemical control measures have been implemented to manage small hive beetle infestations. The use of insecticides to control small hive beetle populations is an emerging management tactic. Currently, very little genomic information exists on insecticide target sites in the small hive beetle. Therefore, the objective of this study is to utilize focused in silico comparative genomics approaches to identify and assess the potential insecticide sensitivity of the major insecticide target sites in the small hive beetle genome. RESULTS: No previously described resistance mutations were identified in any orthologs of insecticide target sites. Alternative exon use and A-to-I RNA editing were absent in AtumSC1. The ryanodine receptor in small hive beetle (Atum_Ryr) was highly conserved and no previously described resistance mutations were identified. A total of 12 nAChR subunits were identified with similar alternative exon use in other insects. Alternative exon use and critical structural features of the GABA-gated chloride channel subunits (Atum_RDL, Atum_GRD, and Atum_LCCH3) were conserved. Five splice variants were found for the glutamate-gated chloride channel subunit. Exon 3c of Atum_GluCl may be a beetle-specific alternative exon. The co-occurrence of exons 9a and 9b in the pH-sensitive chloride channel (Atum_pHCl) is a unique combination that introduces sites of post-translational modification. The repertoire and alternative exon use for histamine-gated chloride channels (Atum-HisCl), octopamine (Atum_OctR) and tyramine receptors (Atum_TAR) were conserved. CONCLUSIONS: The recently published small hive beetle genome likely serves as a reference for insecticide-susceptible versions of insecticide target sites. These comparative in silico studies are the first step in discovering targets that can be exploited for small hive beetle-specific control as well as tracking changes in the frequency of resistance alleles as part of a resistance monitoring program. Comparative toxicity alongside honey bees is required to verify these in silico predictions.

13-Tetradecenyl acetate, a female-produced sex pheromone component of the economically important click beetle Melanotus communis (Gyllenhal) (Coleoptera: Elateridae).

Species-specific behavior-modifying chemicals have been used for more than 50 years for monitoring and management of insect pests of agriculture and human health. Elaterid beetle larvae are among insect pests in soil that are increasingly problematic, in part due to the lack of effective management strategies. However, little is known about the insect-produced chemicals that mediate the reproductive behavior of these pests. We used chemical and behavioral studies to identify, synthesize, and field test the sex attractant pheromone of adults of Melanotus communis, commonly called the corn wireworm, the larvae of which are economically important pests of U.S. crops. Our results indicated that a single female-produced chemical, 13-tetradecenyl acetate, was strongly attractive to conspecific male beetles, and did not appear to attract other species. In field evaluations, male M. communis exhibited a dose-dependent response to this compound. In a trial comparing different slow-release dispensers, a small rubber septum impregnated with the chemical was as effective as and easier to use than a plastic bag dispenser. Given that the sex attractant of this insect consists of a single compound that can be readily synthesized, its development for monitoring and management of the corn wireworm may be economically feasible.

Safety assessment of coleopteran active IPD072Aa protein from Psuedomonas chlororaphis.

The ipd072Aa gene from Pseudomonas chlororaphis encodes the IPD072Aa protein which confers protection against certain coleopteran pests when expressed in genetically modified (GM) plants. A weight of evidence approach was used to assess the safety of the IPD072Aa protein. This approach considered the history of safe use of the source organism and bioinformatic comparison of the protein sequence with known allergenic and toxic proteins. The IPD072Aa protein was assessed for resistance to degradation in the presence of simulated gastric fluid containing pepsin as well as heat stability. There was no hazard identified with the IPD072Aa protein. Furthermore, an acute oral toxicity study found no evidence of adverse effects. Collectively, these studies support the human health safety assessment of the IPD072Aa protein.

Effect of imidacloprid exposure on life history traits in the agricultural generalist predator Paederus beetle: Lack of fitness cost but strong hormetic effect and skewed sex ratio.

A trade-off between life history traits in the evolution of insecticide resistance is common in insects because energy acquisition is mainly channeled for detoxification enzyme production. In addition, sublethal exposure to insecticides may have an effect on the physiology and behaviors of surviving insects. Similar to other agricultural pests, pesticide use may have led to insecticide resistance in populations of Paederus fuscipes Curtis. In this study, we determined the median lethal time of 10 field-collected strains in Taiwan for three insecticides that are commonly employed to manage agricultural pests. We determined that the susceptibility of these strains to cyhalothrin and fenitrothion were similar, with resistance ratios (RRs) ranging from 1 to 4; however, significantly different to imidacloprid (RRs: 1-16). The effect of imidacloprid resistance on the life history traits studied of Paederus beetles was limited; only a prolonged egg incubation period, and adult longevity decreased as imidacloprid resistance increased. Regarding sublethal exposure to imidacloprid, adult sex ratios were female biased in most combinations, though nonsignificant. The quality of offspring, particularly the length of eggs significantly decreased. In addition, a hormetic effect was apparent when the individual was exposed to LT25 and LT50; mean fecundity per female increased from 12.80 ±â€¯8.95 (±â€¯standard error [SE]) to 42.70 ±â€¯13.77 eggs compared with that of the control (7.10 ±â€¯1.32). However, the hormetic effect was inconsistent among the tested strains, possibly because of the difference in insecticide resistance levels given that reproductive compensation was absent among the resistant population.

First assessment of the comparative toxicity of ivermectin and moxidectin in adult dung beetles: Sub-lethal symptoms and pre-lethal consequences.

Among macrocyclic lactones (ML), ivermectin (IVM) and moxidectin (MOX) potentially affect all Ecdysozoan species, with dung beetles being particularly sensitive. The comparative effects of IVM and MOX on adult dung beetles were assessed for the first time to determine both the physiological sub-lethal symptoms and pre-lethal consequences. Inhibition of antennal response and ataxia were tested as two intuitive and ecologically relevant parameters by obtaining the lowest observed effect concentration (LOEC) values and interpolating other relevant toxicity thresholds derived from concentration-response curves (IC50, as the concentration of each ML where the antennal response is inhibited by half; and pLC50, as the quantity of ingested ML where partial paralysis was observed by half of treated individuals) from concentration-response curves. Both sub-lethal and pre-lethal symptoms obtained in this study coincided in that IVM was six times more toxic than MOX for adult dung beetles. Values of LOEC, IC50 and pLC50 obtained for IVM and MOX evaluated in an environmental context indicate that MOX, despite needing more time for tis elimination in the faeces, would be twice as harmful to dung beetles as IVM. This approach will be valuable to clarify the real impact of MLs on dung beetle health and to avoid the subsequent environmental consequences.

Multiplicity-Adjusted Confidence Limits in Risk Assessment with Quantal Response Data.

In risk assessment, it is often desired to make inferences on the risk at certain low doses or on the dose(s) at which a specific benchmark risk (BMR) is attained. At times, [Formula: see text] dose levels or BMRs are of interest, and some form of multiplicity adjustment is necessary to ensure a valid [Formula: see text] simultaneous inference. Bonferroni correction is often employed in practice for such purposes. Though relative simple to implement, the Bonferroni strategy can suffer from extreme conservatism (Nitcheva et al., 2005; Al-Saidy et al., 2003). Recently, Kerns (2017) proposed the use of simultaneous hyperbolic and three-segment bands to perform multiple inferences in risk assessment under Abbott-adjusted log-logistic model with the dose level constrained to a given interval. In this paper, we present and compare methods for deriving multiplicity-adjusted upper limits on extra risk and lower bounds on the benchmark dose under Abbott-adjusted log-logistic model. Monte Carlo simulations evaluate the characteristics of the simultaneous limits. An example is given to illustrate the use of the methods.

Assessment of acute toxicity tests and rhizotron experiments to characterize lethal and sublethal control of soil-based pests.

BACKGROUND: Characterizing lethal and sublethal control of soil-based pests with plant protection products is particularly challenging due to the complex and dynamic interplay of the system components. Here, we present two types of studies: acute toxcity experiments (homogenous exposure of individuals in soil) and rhizotron experiments (heterogeneous exposure of individuals in soil) to investigate their ability to strengthen our understanding of mechanisms driving the effectivness of the plant protection product. Experiments were conducted using larvae of the western corn rootworm Diabrotica virgifera LeConte and three pesticide active ingredients: clothianidin (neonicotinoid), chlorpyrifos (organophosphate) and tefluthrin (pyrethroid). RESULTS: The order of compound concentrations needed to invoke a specific effect intensity (EC50 values) within the acute toxicity tests was chlorpyrifos > tefluthrin > clothianidin. This order changed for the rhizotron experiments because application type, fate and transport of the compounds in the soil profile, and sublethal effects on larvae also influence their effectiveness in controlling larval feeding on corn roots. CONCLUSION: Beyond the pure measurement of efficacy through observing relative changes in plant injury to control plants, the tests generate mechanistic understanding for drivers of efficacy apart from acute toxicity. The experiments have the potential to enhance efficacy testing and product development, and might be useful tools for assessing resistance development in the future. © 2018 Society of Chemical Industry.

Assessment of toxicity and biochemical mechanisms underlying the insecticidal activity of chemically characterized Boswellia carterii essential oil against insect pest of legume seeds.

The present study was undertaken to investigate the insecticidal activity of chemically characterized Boswellia carterii essential oil (EO) and its mode of action against the pulse beetle Callosobruchus chinensis and C. maculatus. GC-MS analysis depicted α-thujene (69.16%), α-Pinene (7.20) and α-Phellandrene (6.78%) as the major components of test EO. EO exhibited absolute toxicity at 0.10µl/ml air against both C. chinensis and C. maculatus following 24h exposure. EO caused a significant reduction in oviposition and further reproductive development at LC50 doses (0.050µl/ml to 0.066µl/ml in air). Compared to control, a significant elevation in ROS level accompanied with impairment in enzymatic (SOD and CAT) and non-enzymatic (GSH/GSSH) antioxidant defense system has been observed in EO exposed insect pest. However, EO has no significant effect on in vivo AChE activity. An absolute protection of Vigna radiata seeds samples exposed to EO at LC90 doses was observed without affecting seed germination. The findings revealed that the B. carterii EO has strong insecticidal potential, hence, it could be recommended as a biorational alternative to synthetic insecticides.

Risk assessment of maize damage by wireworms (Coleoptera: Elateridae) as the first step in implementing IPM and in reducing the environmental impact of soil insecticides.

A survey of maize fields was conducted in northeast Italy from 1986 to 2014, resulting in a dataset of 1296 records including information on wireworm damage to maize, plant-attacking species, agronomic characteristics, landscape and climate. Three wireworm species, Agriotes brevis Candeze, A. sordidus Illiger and A. ustulatus Schäller, were identified as the dominant pest species in maize fields. Over the 29-year period surveyed, no yield reduction was observed when wireworm plant damage was below 15 % of the stand. A preliminary univariate analysis of risk assessment was applied to identify the main factors influencing the occurrence of damage. A multifactorial model was then applied by using the significant factors identified. This model allowed the research to highlight the strongest factors and to analyse how the main factors together influenced damage risk. The strongest factors were: A. brevis as prevalent damaging species, soil organic matter content >5 %, rotation including meadows and/or double crops, A. sordidus as prevalent damaging species, and surrounding landscape mainly meadows, uncultivated grass and double crops. The multifactorial model also showed how the simultaneous occurrence of two or more of the aforementioned risk factors can conspicuously increase the risk of wireworm damage to maize crops, while the probability of damage to a field with no-risk factors is always low (<1 %). These results make it possible to draw risk maps to identify low-risk and high-risk areas, a first step in implementing bespoke IPM procedures in an attempt to reduce the impact of soil insecticides significantly.

Evaluation of Potential Fitness Costs Associated With eCry3.1Ab Resistance in Diabrotica virgifera virgifera (Coleoptera: Chrysomelidae).

Both an eCry3.1Ab-selected and paired control western corn rootworm, Diabrotica virgifera virgifera LeConte, colony were tested for adult longevity, egg oviposition, egg viability, and larval development in order to evaluate the potential fitness costs associated with eCry3.1Ab resistance. Adult longevity experiments were conducted by pairing virgin males and females together in plastic boxes supplied with food, water, and ovipositional medium and observed for survival time. Eggs were also collected from the ovipositional medium once a week to determine average egg oviposition and egg viability. Larval development time experiments were conducted by infesting seedling assays with 25 neonate larvae and recording larval recovery after several days. Adult longevity, average egg oviposition, and larval development time results indicated a lack of fitness costs associated with eCry3.1Ab resistance in the western corn rootworm. Results of egg viability indicated a fitness advantage for the eCry3.1Ab-selected colony with a significantly higher egg hatch than the control.

Toxicity assessment of four insecticides with different modes of action on pupae and adults of Eriopis connexa (Coleoptera: Coccinellidae), a relevant predator of the Neotropical Region.

Pesticides can be toxic to nontarget organisms including the natural enemies of agricultural pests, thus reducing the biodiversity of agroecosystems. The lethal and sublethal effects of four insecticides with different modes of action-pyriproxyfen, teflubenzuron, acetamiprid, and cypermethrin-were evaluated on pupae and adults of Eriopis connexa, an effective predator in horticultural crops. Pupal survival was reduced by pyriproxyfen (26 %) and cypermethrin (41 %). Malformations in adults emerged from treated pupae were observed after acetamiprid (82.7 and 100 % for 100 and 200 mg a.i./l, respectively), pyriproxyfen (48.6 %), and cypermethrin (13.3 %) treatments. A longer mean oviposition time was also observed in adults emerged from pupae treated with cypermethrin. Moreover, the latter insecticide as well as teflubenzuron did not reduce reproductive parameters, whereas females emerged from pyriproxyfen-treated pupae were not be able to lay eggs even when females showed large abdomens. Upon exposure of adults, survival was reduced to approximately 90 % by acetamiprid, but no reduction occurred with pyriproxyfen, teflubenzuron, or cypermethrin though the fecundity at fifth oviposition time of the female survivors was reduced. Pyriproxyfen decreased the hatching at all the oviposition times tested, whereas fertility was reduced in the fourth and fifth ovipositions by teflubenzuron and in the first and third ovipositions by cypermethrin. In conclusion, all four insecticides tested exhibited lethal or sublethal effects, or both, on E. connexa. The neurotoxic insecticides were more harmful than the insect-growth regulators, and pupae were more susceptible than adults. The toxicity of insecticides on the conservation of predators in agroecosystems of the Neotropical Region is discussed.

Assessment of Toxicity, Antifeedant Activity, and Biochemical Responses in Stored-Grain Insects Exposed to Lethal and Sublethal Doses of Gaultheria procumbens L. Essential Oil.

The present study was undertaken to investigate the insecticidal activity of chemically characterized Gaultheria procumbens essential oil (EO) and its mode of action against the Coleopteran insects Sitophilus oryzae and Rhyzopertha dominica. Gas chromatography-mass spectrometry results depicted methyl salicylate (MS) as the major compound (96.61%) of EO. EO and its major compound methyl salicylate (MS) showed 100% mortality at 150 and 5.0 µL/L air against S. oryzae and R. dominica, respectively, on 24 h of exposure. The in vivo percent inhibition of AChE activity ranged between 6.12 and 27.50%. In addition, changes in the antioxidative defense system, superoxide dismutase (SOD), catalase (CAT), reduced glutathione (GSH), and oxidized glutathione (GSSG), in test insects were estimated. A significant dose-dependent response in all test parameters was observed. The results demonstrated that G. procumbens EO could play a significant role in the formulation of EO-based insecticides for the management of stored-grain insects.

Inheritance and Fitness Costs of Resistance to Cry3Bb1 Corn by Western Corn Rootworm (Coleoptera: Chrysomelidae).

Transgenic crops that produce insecticidal toxins derived from the bacterium Bacillus thuringiensis (Bt) are widely planted to manage pest insects. One of the primary pests targeted by Bt corn in the United States is western corn rootworm, Diabrotica virgifera virgifera LeConte (Coleoptera: Chrysomelidae). Cry3Bb1 corn for management of western corn rootworm was commercialized in 2003, and beginning in 2009, populations of western corn rootworm with field-evolved resistance to Cry3Bb1 corn were found in Iowa. Here we quantify the magnitude, inheritance, and fitness costs of resistance to Cry3Bb1 corn in two strains (Hopkinton and Cresco) derived from field populations that evolved resistance to Cry3Bb1 corn. For Hopkinton, we found evidence for complete resistance to Cry3Bb1 corn and nonrecessive inheritance. Additionally, no fitness costs of Cry3Bb1 resistance were detected for Hopkinton. For Cresco, resistance was incomplete and recessive, and we detected fitness costs affecting developmental rate, survival to adulthood, and fecundity. These results suggest that variation may exist among field populations in both the inheritance and accompanying fitness costs of resistance. To the extent that field populations exhibit nonrecessive inheritance and a lack of fitness cost, this will favor more rapid evolution of resistance than would be expected when resistance is functionally recessive and is accompanied by fitness costs.

Establishment of a cell line from the ash and privet borer beetle Tylonotus bimaculatus Haldeman and assessment of its sensitivity to diacylhydrazine insecticides.

A novel cell line, NRCAN-Tb521, was developed from larvae of the longhorn beetle Tylonotus bimaculatus (Coleoptera: Cerambycidae), a pest of North American ash trees. The cell line has been successfully passaged more than 50 times and displayed very strong attachment to the substrate and a modal chromosomal count distribution of 19. Sequencing of a 649 bp fragment of the mitochondrial cytochrome oxidase I gene confirmed the identity of NRCAN-Tb521 as T. bimaculatus. The response of the cell line to 20-hydroxyecdysone and diacylhydrazine ecdysone agonist insecticides was also studied. At 10(-6) M, 20-hydroxyecdysone, tebufenozide, methoxyfenozide and halofenozide triggered the production of numerous filamentous cytoplasmic extensions, and the cells tended to form aggregates, indicative of a cell differentiation response. This response was followed by a strong decrease in viability after 4 d. Reverse transcription polymerase chain reaction (PCR) experiments and sequencing of PCR fragments showed that the 20E receptor gene EcR is expressed in the cells and that 20E, tebufenozide, methoxyfenozide and halofenozide also induce the expression of the nuclear hormone receptor gene HR3. This report establishes that NRCAN-Tb521 is a valuable in vitro model to study effects of ecdysone agonists in wood-boring cerambycids.

EXPLOITING CHEMICAL ECOLOGY FOR LIVELIHOOD IMPROVEMENT OF SMALL HOLDER FARMERS IN KENYA.

"Push-Pull" is an inexpensive and eminently practical strategy designed for developing countries in order to exploit sound principles of chemical ecology for agricultural pest management. This strategy is specifically suitable for small holder farmers. Their experience can easily be integrated into existing farming practices in their immediate environment. "Push-pull" within one and a half decades became widely established and meanwhile is greatly beneficial to practitioners in East Africa, mainly Kenya. The classical push-pull approach used for applied plant-insect management was pioneered by Khan and Pickett (2000) and subsequent papers of Pickett (2003) and Khan et al. (2006, 2008). Relevant plant species explored so far were maize or sorghum intercropped with other East African plants (Desmodium spp. resp. Melinis minutiflora) possessing natural chemicals repellent resp. attractive for stem borer moths Chilo partellus (Lepidoptera), whereby Desmodium spp. was grown inside the maize rows while M. minutiflora surrounded it. Both simultaneous actions combined resulted in a significant decrease of stem borers in the area to be protected. A benefit to cost ratio of 2.5 was realized. Within a period of 15 years the number of subscribing farmers substantially increased from a few dozen to more than 80,000 in 2014. Two experiments along the paths of chemical ecology were undertaken between Sept 2012 and Feb 2013: One was designed to investigate if the legume D. intortum known to produce repellent volatiles against stem borer moths induces defence in Zea mays varieties. We looked at two open-pollinated farmers' varieties and two commercial hybrid varieties suspecting the farmers' varieties to be responsive rather than the hybrids. However, no defence induction was detected in this study so far. This could be explained by an insufficient production of defence inducing volatiles in leaves of D. intortum whereas flowers might produce a sufficient response. More detailed study is needed. A second approach made use of species-specific insect monitoring traps baited with highly specific female sex pheromones for attracting and monitoring destructive insect pests. The female sex pheromone (8-methyl-decane-2-ol propanoate) of Diabrotica virgifera virgifera (Coleoptera: Chrysomelidae) (Western Corn Rootworm) is readily available as bait in the "Metcalf sticky cup trap" for trapping males, an extraordinarily sensitive technique for monitoring the presence or absence of male beetles in a given area. Li et al. (2006) had argued for the likelihood of easy immigration of this cosmopolitan maize pest into East Africa. Our results, however, so far indicate the absence of a local population in the area of Mbita, while not excluding its presence at Nairobi or Mombasa. Both investigations contribute to different aspects of Kenyan economic development and may be seen as two independent but complementary contributions towards livelihood improvement of small holder farmers in Kenya.

Costs of living in metal polluted areas: respiration rate of the ground beetle Pterostichus oblongopunctatus from two gradients of metal pollution.

To address the question about costs of living in polluted areas, biomarkers linked to metabolism were measured in Pterostichus oblongopunctatus (Coleoptera: Carabidae) collected along two metal-pollution gradients in the vicinity of the two largest Polish zinc smelters: 'Boleslaw' and 'Miasteczko Slaskie' in southern Poland. Both gradients covered a broad range of Zn and Cd concentrations in the humus layer (109-6151 and 1.48-71.4 mg kg(-1), respectively) and body metal concentrations increased with increasing soil metal concentrations. The whole-organism respiration rate was measured as oxygen consumption with Micro-Oxymax respirometer, and cellular energy consumption-as the activity of electron transport system, which is linked to cellular respiration rate. The significant increase in the whole-organism respiration rate with the body metal concentration was found when taking into account other factors such as body mass, gradient (or year of sampling as the beetles were collected on the gradients in different years) and the interactions: body metal concentrations × collection date, body metal concentrations × body mass, and body mass × gradient/sampling year. However, no relationships between metal concentrations in soil or body metal concentrations and the whole-organism or cellular respiration rate could be detected when using mean values per site, underlining the crucial importance of incorporating individual variability in such analyses. The observed increase of the whole-organism respiration rate with increasing body contamination with metals suggests that P. oblongopunctatus incurs energetic expenditures resulting from the necessity to facilitate metal elimination or repair of toxicant-induced damage.