Determination of the natural mortality factors of Citrus leafminer (original) (raw)
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The seasonal abundance, parasitoid complex and percentage of parasitism of the citrus leafminer, Phyllocnistis citrella Stainton (Lepidoptera: Gracillariidae) were investigated in three grapefruit orchards in the eastern Mediterranean region in [2005][2006][2007]. Phyllocnistis citrella populations increased during summer months and declined during fall. During the study period, 2-3 peaks of both pest and parasitoid populations were detected on the summer shoots and 1-2 peaks on the fall shoots. At the experimental sites, 10 parasitoid species and unidentified individuals belonging to 2 genera were determined to attack P. citrella. Citrostichus phyllocnistoides Narayanan (Hymenoptera: Eulophidae) was the most abundant parasitoid (72.8%), followed by Cirrospilus brevis Zhu, LaSalle & Huang (11.2%) and C. ingenuus Gahan (Hymenoptera: Eulophidae) (7.1%). Sympiesis striatipes (Ashmead) (Hymenoptera: Eulophidae), was determined for the first time as a parasitoid of P. citrella in Turkey. Parasitism ratio (%) ranged between 39.56-50.67% in Hatay, 42.60-47.61% in Adana and 35.60-41.25% in Mersin during the study years. The highest rates of parasitism were observed at the end of summer and in the fall. It was determined that percent parasitism was significantly correlated with increases of P. citrella density, but did not significantly differ among the study sites and years. The results show that C. phyllocnistoides has an important role among the P. citrella parasitoids present in Turkey due to its frequency.
Biological Control, 2010
The citrus leafminer, Phyllocnistis citrella, is a pest native to Southeast Asia which threatened the citrus industry in the Mediterranean region upon its introduction in 1993. Immediately afterward, a classical biological control program was implemented in Spain. The exotic parasitoid Citrostichus phyllocnistoides was the only introduced parasitoid to become established. In 2006, data on both the incidence of P. citrella and the impact of its natural enemies were collected following the same protocols used in 1997-1999 when C. phyllocnistoides was not yet present. C. phyllocnistoides constituted 99.4% of the parasitoids collected in 2006 corresponding to a decrease in the incidence of P. citrella from 3.2-5.1 to 1.8-2.4 mines per leaf in 1997-1999 and 2006, respectively. Mortality caused by natural enemies on P. citrella in 2006 was 93.3% (18.0% parasitism, 40.8% feeding punctures and 34.5% predation). C. phyllocnistoides, which preferentially parasitizes P. citrella second instar larvae, has displaced most of the indigenous parasitoids that moved onto P. citrella mainly parasitizing third instar larvae, upon its introduction. Because C. phyllocnistoides is an idiobiont parasitoid and preferentially parasitizes P. citrella second instars, this stage has become dominant in the orchards. The shift in the relative abundance of P. citrella larvae has prompted generalist predators to prey mostly on second instars and has contributed to the displacement of the native non-specific parasitoids, which principally utilize third instars, from the system. Both indigenous predators and the introduced parasitoid are key players in the natural regulation of P. citrella.
A survey of parasitoids of the Citrus leaf miner Phyllocnistis citrella Stainton (Lepidoptera: Gracillariidae), was carried out in more than 100 citrus orchards located within 60 km of Valencia. Orchards were sampled all along the citrus growing season from 1995 to 2001. Ten different species were found. The two main species, Pnigalio sp and Cirrospilus brevis Zhu, LaSalle and Huang represented more than 90% of the adults identified. The parasitoids originated from native leafminers living mostly on woody plants. The preferred stages for parasitism were third (27-38% of parasitism rate) and fourth instars (30-53%). Second instar and pupae were less parasitized (10 and 5%, respectively). A program of introduction of exotic parasitoids was carried out between 1996 and 1999. Through a total of 37 shipments coming from nine countries, six species were released in the field. Ageniaspis citricola (Logvinosvskaya) established temporarily but was unable to overwinter. Between 1999 and 2001 Citrostichus phyllocnistoides (Narayanan) expanded to all citrus orchards grown in continental Spain and the Balear Islands, becoming the most abundant parasitoid and displacing native and other introduced parasitoids. Parasitism on second instars increased to 65% and foliar surface damage by the citrus leafminer decreased by 56%.
Biological Control, 2004
A program of introduction of exotic parasitoids for the biological control of the citrus leafminer Phyllocnistis citrella Stainton (Lepidoptera: Gracillariidae) was carried out in Val e encia (Spain) between 1996 and 1999. Eleven species of parasitoids were imported through a total of 37 shipments coming from nine countries. Six species were released in the field, the encyrtid Ageniaspis citricola (Logvinosvskaya), and the eulophids Quadrastichus sp., Semielacher petiolatus (Girault), Galeopsomyia fausta LaSalle, Cirrospilus ingenuus (Gahan), and Citrostichus phyllocnistoides (Narayanan). A. citricola was recovered in summer in many release points, reaching nearly 50% of parasitism and dispersing more than 300 m, but it was not able to overwinter. Quadrastichus sp. and S. petiolatus established temporarily in some sites, but produced little differences in parasitism or density of host population. In 1999, a substantial expansion of C. phyllocnistoides of more than 30 km in all directions was observed from one release point. In 2000 and 2001 this parasitoid expanded to all citrus grown in continental Spain and the Balear Islands, becoming the most abundant parasitoid in all the orchards, and displacing native and other introduced parasitoids. As a consequence, parasitism on second instars increased from less than 16% to 65% and on third instars from 35-38% to 59%. Overall, the mean percentage of parasitism increased from 20-25% to near 60%. Apparently, C. phyllocnistoides reduced by 34% the number of eggs and early instars of the host, and by 72% the number of adults. Damage to citrus foliage decreased by 56%.
Archives of Biological Sciences, 2006
Research was conducted to determine whether Phyllocnistis citrella Stainton (Lepidoptera, Gracillariidae) has any preference in attacking either the upper or the lower surface of the leaves of citrus trees. This investigation took place during the year 1999 at Marathon (Attica, Central Greece) while studying the dispersal of P. citrella on the leaves of three different types of citrus trees. Data on the overwintering and parasitism of P. citrella from different areas in Greece are also presented during the years 1999-2002. In addition, the effect of P. citrella infestationon imidacloprid-treated and untreated tangerine trees was comparatively studied. The parasitoids collected were Pnigalio sp. (Hymenoptera, Eulophidae), Cirrospilus sp. (Hymenoptera, Eulophidae), Neochrysocharis formosa (Westwood) (Hymenoptera, Eulophidae)and Citrostichus phyllocnistoides (Narayanan) (Hym., Eulophidae).
Biocontrol, 2002
Seasonal mortality of the citrusleafminer, Phyllocnistis citrellaStainton, was studied from 1994 through 1998 in`Tahiti' lime, Citrus aurantifolia (Christm.) Swingle,in Homestead, Florida. Survival of eachdevelopmental host stage and the proportionattacked by indigenous and introduced naturalenemies were determined. Before the recovery ofthe introduced parasitoid, Ageniaspiscitricola Logvinovskaya, in 1995, thethird-instar host had the highest averageproportion of parasitized individuals (0.14)followed by the prepupa (0.11) while the firstinstar had the lowest proportion parasitized(0.02). After the first recovery andestablishment of A. citricola, theproportion of pupae parasitized increased to0.56 followed by the prepupa (0.14) and thethird instar (0.11). Before the introduction ofA. citricola, the highest proportion ofhosts killed by predation was observed insecond instar (0.17) and third instar (0.15).After the establishment of the introducedspecies, the proportion of dead individuals dueto predation was greater for second instar(0.31) and third instar (0.21) larvae.Mortality caused by indigenous natural enemieswas significantly correlated with increases ofP. citrella density. Parasitism ofP. citrella by the exotic parasitoid,A. citricola, correlated less well to hostdensity over the season (r2 = 0.12) thandid mortality caused by indigenous naturalenemies (r2 = 0.76). Moreover, a higherpercent mortality in population of P. citrellawas obtained from predation by theindigenous natural enemies than the introducedparasitoid as shown in the mortality estimatesfrom 1995 to 1998.
2006
A survey of parasitoids of the citrus leafminer, Phyllocnistis citrella Stainton (Lepidoptera: Gracillariidae), was carried out in the citrus orchards in the east Mediterranean region of Turkey during 1995-2001. Their relative abundance and rate of parasitism were also determined. Ten species of parasitoids were identified: Cirrospilus sp. nr. lyncus (Walker), C. pictus (Nees), C. variegatus (Masi), C. vittatus Walker, C. ingenuus Gahan, Ratzeburgiola incompleta (Boucek), Diglyphus isaea (Walker), Semielacher petiolatus (Girault), Citrostichus phyllocnistoides (Narayanan), Neochrysocharis formosa (Westwood) (Hymenoptera: Eulophidae). Neochrysocharis sp., Chrysocharis sp., Barycapus sp., Pnigalio sp. (Hymenoptera: Eulophidae) and the Pteromalus sp. (Hym.: Pteromalidae) were also identified. Among these species, R. incompleta in 1995-1996 and C. sp. nr. lyncus in 1997 were the most dominant of all encountered species. In 1998, a new parasitoid species, C. phyllocnistoides, expanded to...
Biological Control, 2004
The parasitoid assemblage associated with the citrus leafminer Phyllocnistis citrella Stainton (Lepidoptera: Gracillariidae) was studied in citrus orchards in eastern Spain over a 7-yr period (1995Ð2001) after the leafminerÕs introduction in 1994. In total, 11,587 adult native parasitoids were collected. To evaluate parasitism, 93,846 live immature stages of the citrus leafminer were observed, of which 21,460 (22.9%) were found to be parasitized. The parasitoid complex recruited around P. citrella was typical for invader hosts: lower species richness, generalized habits, idiobiont strategy, and low to moderate rates of parasitism. Two of the 10 species reared from the citrus leafminer, Pnigalio sp. and Cirrospilus brevis Zhu, LaSalle and Huang, accounted for Ͼ90% of the parasitoids. Native parasitoids moved onto the invading host rapidly, except for C. brevis, which required 3 yr to become common and widespread. In other leafminer species from plants in the vicinity of citrus orchards, the proportion of P. citrella parasitoids was higher in woody (69.7%) than in herbaceous plants (22.2%). The high population levels reached by the new pest, associated with a negative density dependence response of the parasitoids at these high population levels, suggest that the native parasitoid assemblage exerted only a limited role in regulating the population of the new host.
Phyllocnistis citrella and its parasitoids in three citrus species in Greece
Phytoparasitica, 2013
The relative abundance as well as the percentage of parasitism of Phyllocnistis citrella Stainton (Lepidoptera: Gracillariidae) and its parasitoids were studied in a citrus orchard with orange, mandarin and lemon trees in Greece. Infestation of P. citrella on each citrus host, as expressed by the number of mines per leaf, was significantly higher on lemon than on mandarin. The P. citrella parasitoid complex included the native species Neochrysocharis formosa and Pnigalio pectinicornis, as well as the introduced Citrostichus phyllocnistoides. The most abundant of those was N. formosa in all of the citrus species. The average percentage of parasitism was 13.1%, 13.8% and 11.7% on orange, mandarin and lemon, respectively. No significant differences in parasitism rate by each of the three parasitoid species separately were recorded among the three citrus species.
Environmental Entomology, 2005
The parasitoid assemblage associated with the citrus leafminer Phyllocnistis citrella Stainton (Lepidoptera: Gracillariidae) was studied in citrus orchards in eastern Spain over a 7-yr period (1995Ð2001) after the leafminerÕs introduction in 1994. In total, 11,587 adult native parasitoids were collected. To evaluate parasitism, 93,846 live immature stages of the citrus leafminer were observed, of which 21,460 (22.9%) were found to be parasitized. The parasitoid complex recruited around P. citrella was typical for invader hosts: lower species richness, generalized habits, idiobiont strategy, and low to moderate rates of parasitism. Two of the 10 species reared from the citrus leafminer, Pnigalio sp. and Cirrospilus brevis Zhu, LaSalle and Huang, accounted for Ͼ90% of the parasitoids. Native parasitoids moved onto the invading host rapidly, except for C. brevis, which required 3 yr to become common and widespread. In other leafminer species from plants in the vicinity of citrus orchards, the proportion of P. citrella parasitoids was higher in woody (69.7%) than in herbaceous plants (22.2%). The high population levels reached by the new pest, associated with a negative density dependence response of the parasitoids at these high population levels, suggest that the native parasitoid assemblage exerted only a limited role in regulating the population of the new host.