Synthesis of the Sex Pheromone of the Oleander Scale ( Aspidiotus nerii).

A total synthesis of the oleander scale [ Aspidiotus nerii (Bouche)] sex pheromone, the unique sesquiterpenoid containing a cyclobutane moiety of this class of compounds, has been developed. In order to implement this sex pheromone as a new environmentally friendly tool to manage this pest, a more cost-effective, multigram synthesis was required. This new synthetic route, having a Blaise reaction, iron-catalyzed carbon-carbon coupling, and [2 + 2] photocycloaddition reactions as key steps, provides a general access to 4-alkyl lactones as well as a robust access to the target sex pheromone. Starting from readily available compounds as 3-hydroxypropanenitrile, ethyl bromoacetate, and 2-acetyl butyrolactone, the synthetic sequence afforded the A. nerii sex pheromone with minimum intermediate purification and good overall yield in nine linear steps.

Identification, introgression, and validation of fruit volatile QTLs from a red-fruited wild tomato species.

Volatile organic compounds (VOCs) are major determinants of fruit flavor, a primary objective in tomato breeding. A recombinant inbred line (RIL) population consisting of 169 lines derived from a cross between Solanum lycopersicum and a red-fruited wild tomato species Solanum pimpinellifolium accession (SP) was characterized for VOCs in three different seasons. Correlation and hierarchical cluster analyses were performed on the 52 VOCs identified, providing a tool for the putative assignation of individual compounds to metabolic pathways. Quantitative trait locus (QTL) analysis, based on a genetic linkage map comprising 297 single nucleotide polymorphisms (SNPs), revealed 102 QTLs (75% not described previously) corresponding to 39 different VOCs. The SP alleles exerted a positive effect on most of the underlying apocarotenoid volatile QTLs-regarded as desirable for liking tomato-indicating that alleles inherited from SP are a valuable resource for flavor breeding. An introgression line (IL) population developed from the same parental genotypes provided 12 ILs carrying a single SP introgression and covering 85 VOC QTLs, which were characterized at three locations. The results showed that almost half of the QTLs previously identified in the RILs maintained their effect in an IL form, reinforcing the value of these QTLs for flavor/aroma breeding in cultivated tomato.

Single-Layered Hybrid Materials Based on 1D Associated Metalorganic Nanoribbons for Controlled Release of Pheromones.

A new family of stable layered organic-inorganic materials has been prepared, in one-step solvothermal process. They are based on an ordered nickel cluster-type nanoribbons separated from each other by specific alkyl (heptyl- or dodecyl-) arylic mono-carboxylate moieties acting as molecular spacers, perpendicular to the 1D inorganic chains. These organic spacers contain hydrocarbon tails with different length which control the separation level between inorganic 1D sub-units, inhibiting the 3D growth of conventional DUT-8-type metal-organic frameworks (MOFs). The lamellar nature of the materials formed was studied and confirmed by different characterization techniques, showing the structural location of individual organic and inorganic building units. They have been successfully used as a long-lasting biodegradable and water-proof materials for controlled release of chemicals, such as pheromones for sustainable treatment of insect plagues.

Absolute Configuration of the Invasive Mealybug Delottococcus aberiae (De Lotto) Sex Pheromone: Synthesis and Bioassay of Both Enantiomers.

The mealybug Delottococcus aberiae (De Lotto) (Hemiptera: Pseudococcidae) is an invasive pest reported in Europe at the end of the first decade of the 2000s, causing severe damage to citrus production in eastern Spain. In a previous work, (4,5,5-trimethyl-3-methylenecyclopent-1-en-1-yl)methyl acetate was identified as the sex pheromone emitted by females, a new compound with an unusual ß-necrodol skeleton possessing one stereocenter. This compound was assigned to the (-)-enantiomer but the absolute configuration was then not reported. In the present study, enantiomeric pure samples of both enantiomers were synthesized. X-ray diffraction analysis allowed the (-)-enantiomer, identical to the one emitted by virgin D. aberiae females, to be unequivocally identified as (-)-(R)-(4,5,5-trimethyl-3-methylenecyclopent-1-en-1-yl)methyl acetate. Bioassays carried out to test the activity of both enantiomers under field conditions suggest that the presence of the (+)-(S)-enantiomer has detrimental effects on the activity of the racemates.

New Monoterpenoid as the Sex Pheromone of Spanish Populations of the Longtailed Mealybug Pseudococcus Longispinus (Hemiptera: Pseudococcidae).

Pseudococcus longispinus (Targioni-Tozzetti) (Hemiptera: Coccoidea: Pseudococcidae), a polyphagous and cosmopolitan pest native to Australia, is a highly damaging pest for numerous crops of economic importance. The sex pheromone of this species (2-(1,5,5-trimethylcyclopent-2-en-1-yl)ethyl acetate), currently used for pest monitoring purposes, was not attractive to males in field experiments conducted in Spanish persimmon orchards infested with this mealybug. The virgin and mated female volatile profiles of these P. longispinus populations were studied by the volatile collection of effluvia in Porapak-Q. The resulting extracts were analyzed by gas chromatography coupled to mass spectrometry (GC-MS), revealing a new compound specific to virgin females and different from the previously described sex pheromone. Based on GC-MS data and nuclear magnetic resonance experiments, we envisaged monoterpene 2-(1,5-dimethyl-4-methylenecyclopent-2-en-1-yl)ethyl acetate as the new sex pheromone candidate, which was synthesized and shown to be attractive in the field to P. longispinus males of the Spanish population.

Synthesis of new antimicrobial pyrrolo[2,1-a]isoquinolin-3-ones.

The attractive structure of the pyrroloisoquinoline moiety, together with its potential antimicrobial activity, encouraged us to prepare six 8-substituted and seven 8,9-disubstituted-1,2,3,5,6,10b-hexahydropyrrolo[2,1-a]isoquinolin-3-ones in a few steps with good yields. We applied a convenient methodology via double intramolecular cyclization conducted by a Bischler-Napieralski cyclodehydration-imine reduction sequence, which is widely employed in the synthesis of isoquinoline alkaloids. Therefore, we synthesized three series of these pyrrolo[2,1-a]isoquinolin-3-ones characterized by the substituent at the 8-position or 8,9-positions of the aromatic ring: (a) different side chains are attached to an 8-OH group (series 1); (b) a chlorine atom is attached to the 8-position (series 2); and (c) 8- and 9-carbons are bearing an identical group (series 3). The compounds bearing a benzylic moiety at the 8-position, for example, 8-benzyloxy-pyrrolo[2,1-a]isoquinolin-3-one (1a) and 8-(4-fluorobenzyloxy)-pyrrolo[2,1-a]isoquinolin-3-one (1e), as well as, a 8-chloro-9-methoxy moiety including the 8-chloro-9-methoxy-pyrrolo[2,1-a]isoquinolin-3-one (2a), provided the most fungicide and bactericide agents, respectively.

Control of Leiodes cinnamomeus (Coleoptera: Leiodidae) in Cultivated Black Truffle Orchards by Kairomone-Based Mass Trapping.

The monoculture situation of truffle cultivation is favoring the appearance of pests that would not be economically important in naturally balanced forest ecosystems. The most prominent of them is the European truffle beetle Leiodes cinnamomeus (Panzer) (Coleoptera: Leiodidae), for which there are no effective control methods capable of reducing its populations. The potential of the mass trapping technique against this beetle, based on adapted pitfall traps and the semiochemical methyl disulfide as an attractant, is explored in the present work. Two trap densities (40 and 80 traps/ha) were tested in 2-yr field trials carried out in the region of Teruel (Spain) with black truffle cultivation tradition. Kairomone dispensers were placed in the field immediately before adult outbreak and remained active there throughout the season. The efficacy of each treatment was measured according to the reduction in beetle populations and the damaged truffles in the center of the treated areas. The results showed that both trapping densities reduced adult populations (mean 57% catch reduction), but 80 traps/ha were needed to significantly lower damage parameters (>40% reduction), percentage of attacked truffles and number of galleries/g truffle. The cost effectiveness of these treatments and possible improvements are discussed.

Production of Volatile Moth Sex Pheromones in Transgenic Nicotiana benthamiana Plants.

Plant-based bioproduction of insect sex pheromones has been proposed as an innovative strategy to increase the sustainability of pest control in agriculture. Here, we describe the engineering of transgenic plants producing (Z)-11-hexadecenol (Z11-16OH) and (Z)-11-hexadecenyl acetate (Z11-16OAc), two main volatile components in many Lepidoptera sex pheromone blends. We assembled multigene DNA constructs encoding the pheromone biosynthetic pathway and stably transformed them into Nicotiana benthamiana plants. The constructs contained the Amyelois transitella AtrΔ11 desaturase gene, the Helicoverpa armigera fatty acyl reductase HarFAR gene, and the Euonymus alatus diacylglycerol acetyltransferase EaDAct gene in different configurations. All the pheromone-producing plants showed dwarf phenotypes, the severity of which correlated with pheromone levels. All but one of the recovered lines produced high levels of Z11-16OH, but very low levels of Z11-16OAc, probably as a result of recurrent truncations at the level of the EaDAct gene. Only one plant line (SxPv1.2) was recovered that harboured an intact pheromone pathway and which produced moderate levels of Z11-16OAc (11.8 µg g-1 FW) and high levels of Z11-16OH (111.4 µg g-1). Z11-16OAc production was accompanied in SxPv1.2 by a partial recovery of the dwarf phenotype. SxPv1.2 was used to estimate the rates of volatile pheromone release, which resulted in 8.48 ng g-1 FW per day for Z11-16OH and 9.44 ng g-1 FW per day for Z11-16OAc. Our results suggest that pheromone release acts as a limiting factor in pheromone biodispenser strategies and establish a roadmap for biotechnological improvements.

Airborne Pheromone Quantification in Treated Vineyards with Different Mating Disruption Dispensers against Lobesia botrana.

Mating disruption (MD) is widely used against the European grapevine moth (EGVM), Lobesia botrana (Denis and Schiffermüller; Lepidoptera: Tortricidae), by installing passive dispensers or aerosol devices. The present work reports a new sampling and quantification methodology to obtain absolute data about field airborne pheromone concentration based on air samplings and sensitive chromatographic-spectroscopic methods. Samplings were performed in fields treated with passive dispensers or aerosol devices at different moments throughout the crop cycle to study how they act and how the disruption is triggered. Moreover, pheromone adsorption and releasing capacity of vine leaves were studied to elucidate their role in the disruption. Although both types of dispensers were effective in limiting the damage inflicted by EGVM, they performed differently and provided different airborne pheromone concentration profiles. Results also proved that leaves were able to adsorb and release part of the airborne pheromone acting as subsequent and additional pheromone sources. This fact could explain the different concentration profiles. Moreover, our results suggest that lower pheromone emission than that of the current passive dispensers still could provide an adequate performance in the field. Competitive mechanisms involved in MD using both dispensers, the dynamics of the airborne pheromone throughout the time and the importance of the canopy are discussed.

Terretonins E and F, inhibitors of the mitochondrial respiratory chain from the marine-derived fungus Aspergillus insuetus (#).

Two new meroterpenoids, terretonins E and F (1, 2), together with three known compounds, aurantiamine (3), linoleic acid, and uridine, were isolated as fermentation products of the marine-derived fungus Aspergillus insuetus, which was associated with the sponge Petrosia ficiformis. Structures of all isolates were elucidated employing spectroscopic methods, mainly by two-dimensional NMR techniques. Compounds 1-3 showed activity as inhibitors of the mammalian mitochondrial respiratory chain.

Study on the optimum pheromone release rate for attraction of Chilo suppressalis (Lepidoptera: Pyralidae).

Traditional chemical control against Chilo suppressalis Walker is currently being replaced in Spain by new methods based on pheromones. A key step to improve the efficacy of these methods is the determination of the optimum pheromone release rate, which is still uncertain for this pest. In this work, the pheromone release profile and the field performance of a new mesoporous dispenser was compared with a standard commercial dispenser. For this purpose, pheromone loads were extracted from field-aged dispensers and quantified by gas chromatography with flame ionization detector. In addition, a field trial was carried out with traps baited with one, two, or three mesoporous dispensers per trap, as well as with traps containing one standard dispenser. We found that the highest number of field catches did not correspond to the highest pheromone emission rate, which suggests a repellent effect of the insect if the emission is excessive. The results suggest that the attractant activity was maximized by emitting approximately 34 microg/d. The efficacy of the mesoporous dispenser and its possible improvements are discussed.

Sex Pheromone of the Invasive Mealybug Citrus Pest, Delottococcus aberiae (Hemiptera: Pseudococcidae). A New Monoterpenoid with a Necrodane Skeleton.

Native to sub-Saharan Africa, Delottococcus aberiae De Lotto (Hemiptera: Pseudoccidae) is an invasive mealybug that has been recently reported in Europe, seriously damaging citrus production in eastern Spain. In this study, we isolated and determined the structure of the sex pheromone of D. aberiae, to provide a highly specific and effective lure for detecting, monitoring, and potentially controlling this pest. The volatile profile of D. aberiae virgin and mated females was studied by aeration and collection of effluvia in Porapak-Q. The resulting extracts were analyzed by gas chromatography coupled to mass spectrometry (GC-MS), revealing a candidate compound specific of virgin females. GC-MS and nuclear magnetic resonance spectroscopy data evidenced a new compound, (4,5,5-trimethyl-3-methylenecyclopent-1-en-1-yl)methyl acetate, with an unusual ß-necrodol skeleton. This compound was synthesized and shown to be attractive to male D. aberiae in both laboratory and field experiments. A GC analysis using an enantioselective stationary phase and polarimetry analyses of the synthetic enantiomers showed the natural compound emitted by virgin females to be the - enantiomer.

Survey on Drosophila suzukii Natural Short-Term Dispersal Capacities Using the Mark-Release-Recapture Technique.

Spotted wing drosophila, Drosophila suzukii Matsumura (Diptera: Drosophilidae), has become a key pest for soft fruits and cherries in Europe in less than a decade since the first outbreak in 2007. Although this pest's passive dispersal ability has been observed over more than 1400 km in 1 year, active spread has not yet been extensively studied. A mark-release-recapture (MRR) method based on protein-marked flies was employed to determine the flight capacity of D. suzukii. Sterile marked flies were released and recaptured in a trap grid at increasing distances from 10 to 250 m from the releasing point to study flight distance during periods ranging from 3 h to 1 week. MRR experiments were replicated in the presence and absence of host fruits to study how they could affect dispersal behavior. The dispersal capacity of the Mediterranean fruit fly, Ceratitis capitata Wiedemann (Diptera: Tephritidae) was also studied under the same conditions. The results showed a low dispersal ability for D. suzukii, with a daily flight distance below 100 m with no predominant wind. The implications on natural dispersion and control methods based on attractants are discussed.

Evaluation of traps and lures for mass trapping of Mediterranean fruit fly in citrus groves.

Mass trapping has proven to be a powerful weapon in the control of Ceratitis capitata (Wiedemann), and its application in Mediterranean countries has currently increased notably as a control method. In this study, the efficacy of newly developed traps and dispensers of attractants were assessed with the aim of finding the best trap and set the lifetime of the dispensers, thus improving the total efficacy of mass trapping. Efficacy trials with six different types of traps and six different types of female dispensers were carried out. Moreover, the lifetime of three female dispensers, including a new attractant composition dispenser with n-methyl pyrrolidine, were studied. Results show significant differences among the trap types using female attractants, with an advantage of nearly 3 times more catches in best trap. Tested female dispensers showed no significant differences in efficacy between trimethylamine and putrescine attractants regard n-methyl pyrrolidine, however we observed differences in lifetime between dispensers. Thus, there are significant differences among different types of traps and dispensers in efficacy, and the appropriate selection of the trap and dispenser will improve the mass trapping results.

A new long-life trimedlure dispenser for Mediterranean fruit fly.

New agricultural techniques are attempting to reduce the application of synthesized pesticides and replace them with new environmentally friendly methods such as mass trapping, mating disruption, or chemosterilization techniques. All these methods are based on the release of a lure for insect attraction or confusion. The success of the chosen method depends on the quality of the attractant emission from the dispenser. Currently, used dispensers with a polymeric matrix and new dispensers with mesoporous inorganic materials were evaluated to obtain more efficient emission kinetics. In this study, the selected pest was the Mediterranean fruit fly, Ceratitis capitata (Wiedemann) and the lure used was trimedlure (TML). The dispensers were validated by means of a field study comparing insect catches with attractant release values. As a result, we have demonstrated that mesoporous dispensers have a clearly longer lifetime than the polymeric plug. Furthermore, the attractant release rate is less dependent on temperature in mesoporous than in polymeric dispensers.

Improvements in Rhynchophorus ferrugineus (Coleoptera: Dryophthoridae) Trapping Systems.

Improved trap efficacy is crucial for implementing control methods for red palm weevil, Rhynchophorus ferrugineus (Olivier; Coleoptera: Dryophthoridae), based on trapping systems, such as mass trapping, attract and infect or attract and sterilize techniques. Although new trap designs have been proposed and aggregation pheromone dispensers have been optimized, aspects such as the use of co-attractants (molasses) and trap placement are still not well defined and standardized. The efficacy of three concentrations of molasses and different formulations to reduce water evaporation in traps was studied in different field trials to improve trapping systems and to prolong trap servicing periods. In addition, the performance of installing groups of traps or single traps was also evaluated with the aim of improving the attracted/captured weevils ratio. Our results showed that captures increased when molasses were added at 15% to the water contained in the trap and that a thin layer of oil, created by adding 2-3% of paraffinic oil to water, was able to effectively reduce evaporation and prolong trap servicing periods. Moreover, 3.5-fold more weevils were captured when placing five traps instead of one at the same trapping point. Results obtained allow improved efficacy and may have an impact in the economic viability of trapping systems and, therefore, in integrated pest management programs.

Induction of p-coumaroyldopamine and feruloyldopamine, two novel metabolites, in tomato by the bacterial pathogen Pseudomonas syringae.

Inoculation of tomato plants (Solanum lycopersicum cv. Rutgers) with Pseudomonas syringae pv. tomato led to the production of a hypersensitive-like response in this pathovar of tomato. Accumulation of hydroxycinnamic acid amides (HCAA) of tyramine (p-coumaroyltyramine and feruloyltyramine) and dopamine (p-coumaroyldopamine and feruloyldopamine) was detected after bacterial infection. Two of them, p-coumaroyldopamine and feruloyldopamine, are described for the first time. The accumulation of HCAA was preceded by an increment of hydroxycinnamoyl-CoA:tyramine N-hydroxycinnamoyl transferase (THT) gene expression. HCAA also accumulated in transgenic NahG tomato plants overexpressing a bacterial salicylic hydroxylase. However, treatment of plants with the ethylene biosynthesis inhibitor, aminoethoxyvinilglycine, led to a reduction in the accumulation of THT transcripts and HCAA. Together, the results suggest that pathogen-induced induction of ethylene is essential for HCAA synthesis, whereas salicylic acid is not required for this response. In addition, notable antibacterial and antioxidant activities were found for the new HCAA, thus indicating that they could play a role in the defense of tomato plants against bacterial infection.

Isolation and structural elucidation of eight new related analogues of the mycotoxin (-)-botryodiplodin from Penicillium coalescens.

Bioassay-guided fractionation of the organic extract derived from the terrestrial fungus Penicillium coalescens led to the isolation of the known mycotoxin (-)-botryodiplodin (1) and eight new structurally related analogues (2-9). The structures of the novel compounds were determined by MS and NMR studies, including 1D and 2D NMR. A likely biogenetic pathway from the aldehydic open form of 1 (C7 unit, U1) is proposed for these metabolites. Among all the isolated metabolites, only (-)-1 showed antifungal, antibacterial, and insecticidal activity. This latter activity appears to be a new property attributed to (-)-1.

Identification of the Male-Produced Aggregation Pheromone of the Four-Spotted Coconut Weevil, Diocalandra frumenti.

The four-spotted coconut weevil, Diocalandra frumenti Fabricius (Coleoptera: Dryophthoridae), is a small weevil found attacking economically important palm species, such as coconut, date, oil, and Canary palms. Given the scarcity of detection and management tools for this pest, the availability of a pheromone to be included in trapping protocols would be a crucial advantage. Previous laboratory experiments showed evidence for aggregation behavior; thus, our main goal was to identify the aggregation pheromone in this species. The volatile profile of D. frumenti individuals was studied by aeration and collection of effluvia in Porapak-Q and also by solid phase microextraction (SPME) techniques. Moreover, solvent extraction of previously frozen crushed individuals was also performed. All resulting extracts and SPME fibers were analyzed by gas chromatography coupled to mass spectrometry (GC-MS). The comparison of male and female samples provided the candidate compound, 5-ethyl-2,4-dimethyl-6,8-dioxabicyclo[3.2.1]octane (multistriatin), whose biological activity was evaluated in olfactometer and field assays.

Lures for red palm weevil trapping systems: aggregation pheromone and synthetic kairomone.

BACKGROUND: The optimisation of the lure is essential for the implementation of trapping systems to control insect pests. In this work, the response of the red palm weevil (RPW), Rhynchophorus ferrugineus Olivier, to increasing emission rates of its aggregation pheromone (ferrugineol) and the efficacy of a convenient synthetic kairomone based on fermentation odours (ethyl acetate and ethanol) have been evaluated in different years and locations along the Mediterranean basin. RESULTS: In general, although capture data and emission had noticeable variability among locations, significantly fewer RPW were captured in pyramidal Picusan® traps with the lowest ferrugineol emission rates tested (0.6-3.8 mg day-1 ). Captures increased rapidly with ferrugineol emission up to 4-5 mg day-1 ; then, higher emission rates did not improve or reduce captures, up to the highest emission rate tested of 50.9 mg day-1 . Thus, there is no evidence of an optimum release rate corresponding to a maximum of RPW catches. Traps baited with the synthetic kairomone (1:3 ethyl acetate/ethanol) captured 1.4-2.2 times more total weevils than traps baited only with ferrugineol. Moreover, in most of the locations, the synthetic blend was at least as effective as the local coattractants used (plant material + molasses). CONCLUSIONS: Ferrugineol emission rate can vary in a wide range without significantly affecting RPW response. Coattractants based on fermenting compounds, ethyl acetate and ethanol, are able to improve the attractant level of ferrugineol and could be employed to replace non-standardised natural kairomones in RPW trapping systems after further optimisation of their proportions and doses. © 2016 Society of Chemical Industry.