Marcela A. Rodríguez

Susceptibility to Organophosphate Insecticides and Activity of Detoxifying Enzymes in Spanish Populations of Cydia pomonella (Lepidoptera: Tortricidae)

ABSTRACT The mechanisms associated with resistance of codling moth, Cydia pomonella (L.) (Lepidoptera: Tortricidae), to organophosphate insecticides in pome fruit orchards have been shown to depend on the area. Our objectives were to evaluate the susceptibility of Spanish codling moth populations to chlorpyrifos-ethyl, azinphos-methyl, and phosalone, and the activity of three enzymatic systems reported to be involved in resistance. Eleven field populations and a susceptible strain used as a reference were tested using a bioassay consisting in the topical application of a diagnostic concentration on postdiapausing larvae. The enzymatic activity of mixed function oxidases (MFO), glutathione transferases (GST), and esterases (EST) was measured in postdiapausing larvae and adults. A significant decrease in the efficacy of the organophosphates was observed for all field populations, although the decrease was smaller in the case of chlorpyrifos-ethyl. No differences between sexes were detected. In postdiapausing larvae, the activity of the three enzymatic systems was higher in all the field populations than in the susceptible population. The possible implication of EST in codling moth insecticide resistance is reported for the first time in European field populations. In adults, only MFO and GST were implicated. Codling moth resistance to organophosphates in Spanish populations must be taken into account in the implementation of antiresistance strategies.

Identification of a Novel Moth Sex Pheromone Component from Chilecomadia valdiviana

Chilecomadia valdiviana (Philippi) (Lepidoptera: Cossidae) is an insect native to Chile. The larval stages feed on the wood of economically important fruit tree species such as apple, pear, olive, cherry, and avocado, and also on eucalyptus. This causes weakening and, in case of severe infestation, death of the tree. We report identification of the sex pheromone produced by females of this species. Hexane extracts of the abdominal glands of virgin females were analyzed by gas chromatography (GC) with electroantennographic detection, GC coupled with mass spectrometry, and GC coupled to infrared spectroscopy. The major pheromone component was identified as (7Z,10Z)-7,10-hexadecadienal (Z7,Z10–16:Ald), and minor components present in the extracts were (Z)-7-hexadecenal and (Z)-9-hexadecenal, hexadecanal, and (9Z,12Z)-9,12-octadecadienal. Structural assignments were carried out by comparison of analytical data of the natural products and their dimethyl disulfide adducts with those of authentic reference samples. In field tests, traps baited with Z7,Z10–16:Ald captured significantly more males than control traps.

Captures of MFO-resistant Cydia pomonella adults as affected by lure, crop management system and flight

The main resistance mechanism of codling moth (Cydia pomonella) in the tree fruit area of Lleida (NE Spain) is multifunction oxidases (MFO). We studied the frequency of MFO-resistant adults captured by different lures, with and without pear ester, and flights in orchards under different crop management systems. The factor year affected codling moth MFO-resistance level, particularly in the untreated orchards, highlighting the great influence of codling moth migration on the spread of resistance in field populations. Chemical treatments and adult flight were also very important but mating disruption technique showed no influence. The second adult flight showed the highest frequency, followed by the first flight and the third flight. In untreated orchards, there were no significant differences in the frequency of MFO-resistant individuals attracted by Combo and BioLure. Red septa lures baited with pear ester (DA) captured sufficient insects only in the first generation of 2010, obtaining a significantly lower proportion of MFO-resistant adults than Combo and BioLure. In the chemically treated orchards, in 2009 BioLure caught a significantly lower proportion of MFO-resistant adults than Combo during the first and third flight, and also than DA during the first flight. No significant differences were found between the lures or flights in 2010. These results cannot support the idea of a higher attractiveness of the pear ester for MFO-resistant adults in the field but do suggest a high influence of the response to the attractant depending on the management of the orchard, particularly with regard to the use of chemical insecticides.

CATALOGO CRITICO Y NOMINAL DEL GENERO DARGIDA WALKER 1856 (LEPIDOPTERA, NOCTUIDAE, HADENINAE)

El presente catalogo consiste en la lista alfabetica de los nombres de las especies pertenecientes al genero Dargida Walker, 1856 y que fueron descritas antes del 1 de junio del 2003. Strigania Hampson, 1905 y Faronta Smith, 1908 son sinonimos de Dargida Walker, 1856 por comparacion de las especies tipo de cada genero. El tratamiento dedicado a cada taxon especifico incluye su sinonimia confirmada por citas y una mencion de la localidad tipo. Como resultado, se obtiene una lista de 53 especies asignadas al genero Dargida Walker. Se entregan 14 nuevas combinaciones

Monitoring resistance of Cydia pomonella (L.) Spanish field populations to new chemical insecticides and the mechanisms involved

BACKGROUND Widespread resistance of Cydia pomonella to organophosphates was demonstrated in populations from the Spanish Ebro Valley area which showed high levels of enzymatic detoxification. To determine the efficacy of new insecticides, neonate larval bioassays were carried out on 20 field codling moth populations collected from three different Spanish apple production areas. Synergist bioassays were performed to determine the enzymatic mechanisms involved. RESULTS The least active ingredients were methoxyfenozide, with 100% of the populations showing significantly lower mortality than the susceptible strain, and lambda-cyhalothrin, with very high resistance ratios (872.0 for the most resistant field population). Approximately 50% of the populations were resistant or tolerant to thiacloprid. By contrast, tebufenozide was very effective in all the field populations, as was chlorpyrifos-ethyl despite its widespread use during the last few years. Indoxacarb, spinosad and chlorantraniliprole also provided high efficacy, as did emamectin and spinetoram, which are not yet registered in Spain. CONCLUSION The resistant Spanish codling moth populations can be controlled using new reduced-risk insecticides. The use of synergists showed the importance of the concentration applied and the difficulty of interpreting results in field populations that show multiple resistance to different active ingredients.

Target-site mutations (AChE and kdr), and PSMO activity in codling moth (Cydia pomonella (L.) (Lepidoptera: Tortricidae)) populations from Spain

Abstract Codling moth, Cydia pomonella (L.) is a key pest of global importance that affects apple fruit production and whose populations have developed resistance to insecticides in many apple production areas. In Spain, enhanced cytochrome P450 polysubstrate monooxygenase (PSMO) activity is the main mechanism involved in insecticide detoxification by codling moth, although acetylcholinesterase (AChE) target site mutations have been described in two populations. However, the extent of AChE and knockdown resistance (kdr) mutations in Spain is unknown. To assess the actual occurrence of AChE and kdr mutations concurrently with the frequency of moths with PSMO enhanced activity (R-PSMO), 32 Spanish field populations from four apple-growing areas of Spain and two susceptible laboratory strains were evaluated. R-PSMO was significantly higher in 23 chemically treated field populations from Extremadura, Catalonia and Aragon, with proportions that varied between 25% and 90%, but no significant differences among strains and the non-chemically treated orchards (organic or abandoned) were observed. The AChE mutation (F290 V) was detected in all field populations from Catalonia (n = 21) and in three field populations from Aragon (n = 5), with resistant phenotype proportions varying from 34.2% to 97.5% and from 7.2% to 65% in Catalonia and Aragon, respectively. In addition, the kdr mutation (L1014F) was detected in twelve Catalonian field populations, at rates of incidence ranging between 2.6% and 56.8%. A positive correlation between R-PSMO and AChE mutation was found. The origin of the mutations and their ability to persist and spread in field populations with different management systems is discussed.

Monitoring resistance of Cydia pomonella (L.) Spanish field populations to new chemical insecticides and the mechanisms involved: C. pomonella resistance to new insecticides

BACKGROUND Widespread resistance of Cydia pomonella to organophosphates was demonstrated in populations from the Spanish Ebro Valley area which showed high levels of enzymatic detoxification. To determine the efficacy of new insecticides, neonate larval bioassays were carried out on 20 field codling moth populations collected from three different Spanish apple production areas. Synergist bioassays were performed to determine the enzymatic mechanisms involved. RESULTS The least active ingredients were methoxyfenozide, with 100% of the populations showing significantly lower mortality than the susceptible strain, and lambda-cyhalothrin, with very high resistance ratios (872.0 for the most resistant field population). Approximately 50% of the populations were resistant or tolerant to thiacloprid. By contrast, tebufenozide was very effective in all the field populations, as was chlorpyrifos-ethyl despite its widespread use during the last few years. Indoxacarb, spinosad and chlorantraniliprole also provided high efficacy, as did emamectin and spinetoram, which are not yet registered in Spain. CONCLUSION The resistant Spanish codling moth populations can be controlled using new reduced-risk insecticides. The use of synergists showed the importance of the concentration applied and the difficulty of interpreting results in field populations that show multiple resistance to different active ingredients.

Determination of the Baseline Susceptibility of European Populations of Cydia pomonella (Lepidoptera: Tortricidae) to Chlorantraniliprole and the Role of Cytochrome P450 Monooxygenases

The codling moth, Cydia pomonella (L.) (Lepidoptera: Tortricidae), is the key pest on pome fruit and walnut orchards worldwide. Its resistance to available insecticides has been widely reported. Chlorantraniliprole is an anthranilic diamide that was introduced in European countries in 2008-2009 and acts by activating the insects ryanodine receptors. The aims of this study were to determine the baseline susceptibility of European populations of C. pomonella to chlorantraniliprole, to establish the discriminant concentrations (DC) to check the possible development of resistance, and to know the role of cytochrome P450 monooxygenases (P450) in the possible susceptibility decrease of field populations to the insecticide. Ten field populations from Spain along with others were used to calculate the baseline response of larvae to chlorantraniliprole incorporated into the diet. A pooled probit line was calculated, and three DC were established: 0.3 mg a.i./kg (close to the LC50), 1.0 mg a.i./kg (close to the LC90), and 10 mg a.i./kg diets (threefold the LC99). The DC were used to test the susceptibility of 27 field populations from France, Germany, Hungary, Italy, and Spain. The corrected mortality observed in all cases ranged within the expected interval, even with Spanish populations that showed between 12.1 and 100.0% of individuals with high P450 activity. However, the mortality caused by the DC0.3 decreased as the mean P450 activity increased. Field populations resistant to other insecticides were susceptible to chlorantraniliprole. The determined baseline codling moth susceptibility is a valuable reference for tracking possible future alterations in the efficacy of the insecticide.

DESCRIPCION DE LAS ESTRUCTURAS GENITALES Y ESTADOS INMADUROS DE PSEUDOCERURA THORACICA BUTLER, 1882 (LEPIDOPTERA: NOCTUIDAE: CUCULLIINAE)

RESUMEN Se describe el huevo, larva de ultimo estadio y pupa de Pseudocerura thoracica Butler, 1882. Cada uno de estos estados de desarrollo se incluyen en las claves de inmaduros de Olivares et al. (en prensa), Angulo & Weigert (1975) y Angulo & Olivares (2001). Se describen las estructuras de la armadura genital del macho y de la hembra para complementar la informacion morfologica de la especie. Se entregan fotos y dibujos de los distintos estadios de desarrollo

TRES NUEVAS ESPECIES DEL GENERO SCRIPTANIA HAMPSON 1905, EN CHILE (LEPIDOPTERA: NOCTUIDAE: HADENINAE)

Se entrega la descripcion de tres nuevas especies pertenecientes al genero Scriptania Hampson, 1905. Las diagnosis de estas estan basadas en las estructuras externas e internas (genitalia) de los adultos. Estas especies presentan distintas localidades de Chile. El material utilizado para las descripciones proviene de recolectas en terreno, para una de las especies y de material sin identificar depositado en las Colecciones Cientificas de la Universidad de Concepcion, Concepcion - Chile (UCCC) y Smithsonian Institution, National Museum of Natural History, Washington - USA (USNM), para las dos especies restantes