Parasitoids

The california red scale (CRS) aonidiella aurantii (Maskell) is a hemipteram armored scale that infests citrus all over the world. Thus, the natural enemy complez of CRS has been widely studied and especially the most effective natural enemies controlling CRS, the aphelinid ectoparasitoids of the aphytis howard genus (Rosen and DeBach 1979). Aphytis melinus DeBach is considered the most successful and widespread biological control agent of this micro-wasp genus (Murdoch et al. 1989, DeBach and rosen 1991. Foster et al. 1995). Other Aphytis speies, whitch can be found in many countries on CRS as native or introduced parasitoids, are Aphytis chrysomphali (Mercet) and Aphytis lignamenesis compere (Luck and podoler 1985. Asplonao and Garcia-mari 2002).

The Valencia region (eastern spain) is the most extended citrus area in Europe, and citrus is the most important production in Spanish Mediterranean agriculture. Aonidiella aurantii was fist found as a pest in the locality of alzira (valencia) in 1986 (Garcia-mari et al. 1988, Alfaro et al. 1991) and since then, it has slowly expanded to almost all the citrus orchards. The parasitoid A. chrysomphali is considered a native species initially parasitizing chrysomphatus dictyspermi (Morgan) (mercet 1912). It has also been described parasitizing chrysomphatus aonidum (Linnaeus), Aonidiella aurantii, and Aonidiella citrine (Coquillet) (DeBach and rosen 1991). As a. citrine (Coquillet) (Debach and rosen 1991). As A. citrine is not present in Spain and C. dictyospermi and C. aonidum are nowadays almost absent (franco et al. 2006), no other hosts are present apart from CRS. Aphytis melinus has been recared and released in the field dsince 1976 (Melia and Blasco 1980) to prevent a predictable expansion of the pest. Since 1995. A. lingnanensis has also been released in different areas (Verdu and pina 2007). Previous studies in valencia on A. autantii parasitoids present in the field have been performed in a reduced number of orchanrds; observations between 1988 and 1994 yielded almost 100% of A. chrysomphali and 22% of A. melinus.

Here we examine the seasonal abundance and variation of the two more extended California rd scale parasitoids throughout the year and their geographical distribution in relation to the weather conditions. We use field data and literature on the behavior of Aphytis species underdifferent temperature and humidity conditions to identify the mechanisms of coexistence between A, chrysomphali and A. melinus. The coesistence or displacement between Aphytis species in the field in five spatially divided agroecosystems in examined and related to the coexistence of A. melinus and the niche partitioning between both parasitoids species are analyzed

El piojo rojo de California (CRS) Aonidiella aurantii (Maskell) es una escala blindado hemipteram que infesta cítricos en todo el mundo. Por

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