Mating disruption (MD) is widely used against the European grapevine moth (EGVM),
(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.
Spotted wing drosophila,
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
. 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,
Wiedemann (Diptera: Tephritidae) was also studied under the same conditions. The results showed a low dispersal ability for
, 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.
Studies about the sex pheromone of the mealybug Dysmicoccus grassii, a main pest of Canary Islands banana cultivars, showed strong evidence that (−)-(R)-lavandulyl propionate and acetate in a 6:1 ...ratio are principal components of it. Volatile collection and GC-MS analysis from aeration of virgin females allowed the structural elucidation of the compounds. The activity and stereochemistry of both substances were established by means of relative attraction of mealybug males to synthetic standards in competitive Petri dish bioassays. (R)-Lavandulyl propionate induced a stronger attractive effect when compared to (R)-lavandulyl acetate. The attractiveness of the mixture of the two compounds at the original source ratio showed no statistically significant difference from that of the sum of each of the single compounds alone, suggesting that both components are not synergistic but additive.
The effect of using low densities of different dispensing technologies on mating disruption of the striped rice stem borer, Chilo suppressalis Walker, was evaluated in the rice-growing area of ...Valencia (Spain) from 2011 to 2013. The reduction of the current number of release points (30 polymeric dispensers/ha) was investigated by installing 3 aerosol devices per ha (Experiments 1 and 2) or with clusters of hand-applied dispensers (10 or 5 release points/ha; Experiment 3). The influence of pheromone blend on disruption was also studied by loading aerosol devices with the three-component blend or only the main pheromone compound, Z-11-hexadecenal. Results showed that the installation of 3 aerosol devices/ha or clusters of passive dispensers (total dose: 6.6–7.9g/ha) proved equally effective as the conventional treatment with 30 Selibate®CS dispensers/ha (~5g/ha), reducing damage below 1% of infested plants. Although the treatment with 3 aerosol devices/ha loaded with Z-11-hexadecenal provided control of damage comparable to the conventional mating disruption treatment, the higher captures recorded suggest that mating disruption with the incomplete pheromone blend is only slightly effective in the tested conditions. These changes in the number of point sources and pheromone blend could represent important advantages for the implementation of mating disruption against C. suppressalis.
Display omitted
•Mating disruption with sparse pheromone sources is efficacious against C. suppressalis.•Use of mechanical aerosol dispensers has proven effective for rice crops.•The use of aerosol dispensers can be replaced with clusters of passive dispensers.•Efficacy of incomplete pheromone blend could be weaker and need further research.
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.
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
μ
g g
-1
FW) and high levels of Z11-16OH (111.4
μ
g 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.
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.
Since the discovery of Lobesia botrana Denis & Schiffermüller (Lepidoptera: Tortricidae) sex pheromone, it has played an important role in the control and detection of this pest, for example, through ...the use of pheromone‐baited traps and mating disruption techniques. Rubber septa are the most common pheromone dispensers used in monitoring traps, but often dispenser performance is not optimized. The key to improve methods based on pheromones as attractants (monitoring, mass trapping, or ‘attract and kill’) is to know the optimum emission interval, because release rates can strongly affect the attraction. In this work, five levels of pheromone load with different release rates were compared in traps using mesoporous pheromone dispensers to investigate the optimum release rate maximizing L. botrana catches. Residual pheromone loads of the dispensers were extracted and quantified by gas chromatography, to study release profiles and to estimate the various emission levels. The efficacy of pheromone emission was measured in field trials as number of moths caught. A quadratic model was fitted to relate the numbers caught vs. the daily emission rates. The resulting quadratic term was statistically significant, confirming the existence of a relative maximum for L. botrana catches. Taking into account that the trial was carried out only in one location, an optimum emission value of ca. 400 μg per day could be considered to enhance the attraction of L. botrana under West‐Mediterranean weather conditions.
Circumdatin H (1), a new alkaloid from the culture broth of Aspergillus ochraceus, has been isolated, together with a known circumdatin, circumdatin E (2) and other known compounds: flavacol (3) and ...stephacidin A (4). The structure of 1 was established on the basis of chemical and spectral evidence. All of these alkaloids showed biological activity as inhibitors of the mammalian mitochondrial respiratory chain.
PDF
