Abstract. An outbreak of the livestock viral disease bluetongue (BT) was detected during September and October 2000 in the Balearic Islands, Spain. Due to the lack of information about the species of Culicoides (Diptera: Ceratopogonidae) reported in the affected area, six farms in Majorca, four in Minorca and one in Ibiza were selected to carry out surveillance of Culicoides adults using light traps. Here, for the first time, we report the presence in the Balearic Islands of Culicoides imicola Keiffer, the main vector of BT, and the Culicoides obsoletus Meigen group.

Field evaluation of female‐targeted trapping systems for the Mediterranean fruit fly Ceratitis capitata (Wied.) was carried out in a Citrus orchard in Majorca (Spain). Traps and lures included: IPMT and Tephri traps, both baited with a three‐component food‐based synthetic attractant 3FA (composed of putrescine, ammonium acetate and Trimethylamine) as well as IPMT‐baited with Nu‐Lure, and Delta traps baited with Trimedlure. The 3FA food‐based synthetic attractant was set up either wet (containing water) or dry (without water) in IPMT and Tephri traps. Two experiments were conducted, the first during autumn/winter conditions and high Medfly population levels, and the second during spring conditions and low population levels. The results obtained show that the 3FA was very effective at capturing females at high and low population levels. In the first experiment the best performance was shown by the Tephri trap baited with 3FA in combination with water, and in the second the best was also the Tephri trap but with dry treatment. The high number of non‐targeted insects captured by the first treatment together with servicing difficulties would indicate that the 3FA/dry‐baited Tephri trap is the best choice in the area of the study. On the other hand the 3FA captured a percentage of mated females equivalent to those obtained with Nu‐Lure. The Trimedlure proved to be an adequate tool to detect the earliest Medfly males in increasing spring population. The implications and advantages of using the 3FA female attractants in sterile insect technique programmes and mass trapping approaches, are discussed.

To develop new population control methods for the Mediterranean fruit fly, Ceratitis capitata, a study comparing bait application techniques (BAT) with a female‐biased mass trapping strategy was carried out in seven citrus orchards in Mallorca (Balearic Islands, Spain). In the BAT treatment, fenthion, lambda‐cyhalothrin and spinosad were applied separately in three of the orchards. In the other three, the mass trapping strategy (Probodelt traps baited with Biolure©) was adopted at a density of 50 traps/ha, reinforced when necessary with the same insecticide bait application (MTR). The seventh orchard was organically farmed and only mass trapping was used for control, but with a higher trap density (80 traps/ha). For pest monitoring, 2 traps/ha baited with Biolure© (for females and males) and 2 traps/ha baited with trimedlure (for males only) per orchard were inspected weekly. The most effective treatment was the MTR (with fenthion) programme, reducing the C. capitata female population by up to 68% [an average of 3.9 females/trap/day (f/t/d) were obtained vs. 12.6 f/t/d from BAT]. However, the lowest average C. capitata population (between the MTR programmes) was obtained by mass trapping supplemented with lambda‐cyhalothrin (only 3.3 f/t/d). When only BAT was applied, applications with lambda‐cyhalothrin proved to be the most effective (7.1 f/t/d). However, MTR carried out in the organic orchard resulted in the lowest female captures (2.0 f/t/d). Very little fruit damage was recorded in the treatment orchards. In all BAT treatments, the relative number of males and females was similar; however, in the MTR treatments fewer females than males were recorded in the same orchard.

This paper compares the results obtained when analysing the population density of the Mediterranean fruit fly (Ceratitis capitata [Wiedemann]) by standard methods and kriging interpolation. The data used were collected during a pest control experiment involving mass trapping of the females of this species in a citrus orchard. These captures provided a series of diagrams showing the heterogeneous spatial distribution of the flies. Since trapping began at the end of June, the insects were first caught preferentially in trees at the western and southern borders of the orchard. As the number of flies grew the rest of the crop was invaded. Kriging provided information that would allow more efficient pest management by focusing control efforts on areas where target populations are at their largest.Additional key words: Ceratitis capitata, kriging, mass trapping, pest management, spatial distribution. ResumenDistribución espacio-temporal de las capturas de la mosca mediterránea de la fruta (Diptera: Tephritidae) en una parcela de cítricos en MallorcaEn este trabajo se comparan los resultados obtenidos al evaluar la densidad poblacional de una plaga mediante el método de muestreo convencional y el procesado de los mismos mediante kriging. Para ello se utilizaron los datos obtenidos durante un experimento de control de la mosca mediterránea de la fruta Ceratitis capitata (Wiedemann) a base del trampeo masivo de hembras en una plantación de cítricos, obteniéndose una serie de diagramas que muestran la distribución espacial heterogénea de las capturas en la parcela. Se observa como al iniciarse éstas a final de junio, se localizan preferentemente en los árboles situados en los bordes occidental y sur de la plantación, para luego ir invadiendo todo el cultivo a medida que aumenta el nivel del insecto. El uso del kriging se muestra en este estudio como una eficaz herramienta para el manejo de plagas, aportando información que permite aplicar de forma más precisa los métodos adecuados para su control, concentrándolos en las zonas en las que hay mayor densidad poblacional.Palabras clave adicionales: Ceratitis capitata, control de plagas, distribución espacial, kriging.

A pest management programme using the chemosterilant lufenuron against the Mediterranean fruit fly, Ceratitis capitata in Mallorca (Spain) is reported. The aim of this field trial was to monitor the reduction on C. capitata population and fruit infestation during the second and third years of an overall pest control programme. The insect growth regulator lufenuron (a phenylbenzoylurea) was placed within a Sevep device baited with the synthetic, female attractants (ammonium acetate, putrescine and amines), as well as the male attractant trimedlure (TML). A total of 7200 devices were placed on 300 ha within the municipalities of the Sóller Valley, at a density of 24 devices/ha. In order to measure the effectiveness of the chemosterilization, the C. capitata population was evaluated by Probodelt traps, baited either with the synthetic food attractants or TML, placed in three citrus orchards located at different altitudes. Fruit infestation was also evaluated. Results showed an average of 20% reduction in adult medfly population (37.2% for males vs. 2.7% for females). However, high differences were observed among the different orchards. In Site 1, where fallen oranges fruits were removed and phytosanitary treatments were applied, female captures decreased by 63.28%. Whereas at Site 2, where fallen fruits were neglected and no insecticide was applied, female captures increased by 19.90%. Ceratitis capitata population increase placed in Site 2 was probably due to the presence of unmanaged or mismanaged surrounding orchards. Summing up, it seems that the method based on lufenuron applied in the Sóller Valley was successful in decreasing medfly population, but the presence of the nearby improperly managed citrus orchards, as well as other hosts fruit trees for C. capitata, decrease the efficacy of the method.

Globodera pallida is a serious economic pest in worldwide planting of potatoes due to the severe crop losses they can cause. This study aimed to determine the relationship between soil temperature [degree-day accumulation (DD4)]and population development of G. pallida under the agroecological conditions of the Balearic Islands, Spain. Population changes were studied in ‘Marfona’ and ‘Maris Peer’ potato cultivars for three growing seasons. Differences in thepattern of occurrence of nematode life stages on the two potato cultivars were observed. In Maris Peer trials,  secondstage juveniles (J2) hatching occurred about one month after planting (29 and 35 days), J2 root invasion at 57-56 days, and females in roots at 77 days with 540 DD4. In Marfona trials, these nematode stages occurred at 18-31days, 45-52 days and 59-73 days, the last one with 400 DD4. Hence, in Mallorca, G. pallida populations require at least 100 DD4 more in Maris Peer early potato than in the Marfona to reach the adult stage. Senescence in Maris Peer crops happened before most of the females have become brown cyst, suggesting that in this area the Maris Peer early cultivar could exert trap crop effects. The Marfona crop yield obtained at highest level of nematode infestation may indicate thatMarfona seems to be more tolerant to G. pallida than Maris Peer. The results contribute to the knowledge of thermaltime requirements of G. pallida populations under Mediterranean environmental conditions and can be a valuable tool to develop potato cyst nematode control strategies.

Potato (Solanum tuberosum) is one of the most important crops in the Balearic Islands with a yield of 35,000 t in 2004, distributed in 1,100 ha and mostly located in the Sa Pobla Region of Mallorca Island. Potato cyst nematode (PCN) species are widespread in potato crop regions of the Iberian Peninsula and Canary Islands, but only Globodera pallida is known to be present in Sa Pobla (1) where it causes significant yield reductions if it is not properly managed. In the spring of 2000, goldencolored females were detected in several root samples of plant potatoes. In 2001, 2002, and 2003, soil and root samples were collected at harvest from 28 fields to identify and quantify PCN species in this area. According to the European Plant Protection Organization (EPPO) diagnostic protocol, the identification of Globodera spp. populations was based on: (i) morphological and morphometrics characteristics of cyst vulval area and stylets of second-stage juveniles; (ii) protein electrophoresis patterns by isoelectric focusing (2); and (iii) DNA analysis by random amplified polymorphic DNA polymerase chain reaction techniques (2). PCN infestation was detected in 16 potato fields sampled. Mixed populations of G. rostochiensis and G. pallida were found in 14 fields distributed all around Sa Pobla, while two fields contained only G. pallida. The proportion of G. rostochiensis in mixed populations was low, rarely exceeding 20%. The origin of G. rostochiensis introduction in Mallorca is unknown since there is no direct link with other potato-growing areas of Spain. To our knowledge, this is the first report of G. rostochiensis in the Balearics Islands. The identification of G. rostochiensis in the Sa Pobla potato-production fields is very important for the development of a successful integrated pest management (IPM) program in this region. References: (1) M. L. Martinez-Beringola et al. Nematol. Medit. 15:183, 1987. (2) S. K. Ibrahim et al. Pest Manag. Sci. 57:1068, 2001.

Honeybee populations around the world are experiencing a decrease in colony numbers probably due to a combination of different causes, such as diseases, poor nutrition and frequent applications of insecticides to control pests. Previous studies about the effect of pesticide Bacillus thuringiensis subsp. kurstaki (Btk) on Apis mellifera L. report different results. The aim of this study was to analyze the effect of field aerial applications of Btk on bee colony performance, specifically on the brood cell percentage evolution, which can be used as an indicator of queen health and brood development breeding rates. To achieve it, the brood cell surface was photographed in every sampling, and data were analyzed using a method based on image treatment software. A total of 480 pictures were examined from two groups of four nucleus hives in two areas, one receiving aerial spraying with Btk and the other without treatment. A mixed factorial design was realized to analyse the data showing no differences in colony performance between the two groups of colonies either before the treatment, during and at the end of the assay. Furthermore, the brood surface ratio of Btk-treated/untreated increased along the experiment. Therefore, the results of the present study suggest that Btk aerial applications did not affect the brood development of honeybees under natural conditions. Nevertheless further field studies are required to ascertain a safe use of Btk in forest pest management.