LIBRO-CONGRESO-CITRUS

S16P25
Assessment of trophic interactions among citrus mites by DNA-based gut content analysis.
Pérez-Sayas C., Pina T., Gómez-Martínez M.A., Jacas J.A., and Hurtado M.A.
Universitat Jaume I de Castelló (UJI), Ciencias Agrarias y del Medio Natural, Spain. mhurtado@uji.es
Tetranychus urticae Koch and Panonychus citri (McGregor) (Acari: Tetranychidae) are the most important
tetranychid mites affecting citrus orchards in the Region of Valencia (Eastern Spain). Their main natural
enemies are different phytoseiid mites. These predators can prey on both tetranychid mite species but their
actual effect in the field remains unknown. The analysis of the phytoseiid’s gut content using molecular
techniques can provide a new tool to quantify predation. These techniques can reveal the real prey spectrum
of a polyphagous predator, and the range of predators feeding on a particular species. Squash-capture and
tissue-print of field-collected phytoseiid mites followed by Multiplex PCR has revealed to be a valid alternative
to classic taxonomy for mite identification. Furthermore, it has allowed establishing prey preferences and
mite trophic interactions under real field conditions. In the citrus agroecosystem, the specialist Phytoseiulus
persimilis Athias-Henriot clearly prefers T. urticae even when this prey is scarce, whereas the generalist
pollen-feeder Euseius stipulatus (Athias-Henriot) behaves as an omnivorous species that does not seem to
prey preferentially on T. urticae even when this species is highly abundant.
S16P26
Effectiveness and economics of a novel proactive approach for managing the Citrus Rust Mite in
Texas.
Setamou M., and Sekula D.
Texas A&M University-Kingsville Citrus Center (TAMUK-CC), Agriculture, Agribusiness and Environmental Sciences, USA.
mamoudou.setamou@tamuk.edu
The Citrus Rust Mite (CRM), Phyllocoptruta oleivora (Ashmead) (Acari: Eriophyidae), is considered the most
economically important pest affecting citrus production in Texas citrus because the majority of citrus produced
is destined for fresh fruit market. Feeding damage of the pest causes conspicuous injury to fruit leading to
blemish and discoloration of the rind. In light of the absence of any effective alternative CRM control method,
the use of chemical miticides is the only management strategy used by growers. Traditionally, growers scout
for mite population on fruit and once a certain population level is reached starting from April-May, they
decide to begin spraying. This traditional approach provides temporary control of CRM in citrus orchards.
Since CRM also reproduces on leaves and citrus trees have evergreen vegetation, effective control will require
targeting CRM when its populations are at their lowest during the dormant period. Thus, pre-bloom proactive
spray initiation dates were compared to the traditional post-bloom date. Significant and long term reduction
of CRM densities were observed with the proactive spray programs. The gross returns were 1.1 to 1.3-fold
higher with the proactive spray. This novel approach also preserves predatory mite populations which would
provide additional control to various mites. Although this novel approach did not reduce chemical input and
associated costs of control, the better CRM control achieved made its adoption an effective alternative both
ecologically and economically.
S16P27
Spider mite response in citrus rootstocks is mediated by the oxylipin pathway.
Agut B. 1 , Hurtado M.A. 1 , Jacas J.A. 1 , and Flors V. 2
1 Universitat Jaume I (UJI), Unitat Associada d’Entomologia IVIA-UJI, Spain; and 2 Universitat Jaume I (UJI), Metabolic Integration and
Cell Signaling Group, Spain. bagut@uji.es
Citrus rootstock selection has been traditionally based on their resistance to pathogens and tolerance to
abiotic stresses. However, the resistance to arthropod pests has been consistently neglected. Recently,
it has been shown that citrus rootstocks can influence the life history of the phytophagous spider mite
Tetranychus urticae Koch (Acari: Tetranychidae). To compare the usefulness of pathogen resistance-based
rootstock selection with arthropod tolerance/resistance, we have performed comparative experiments of
XII INTERNATIONAL CITRUS CONGRESS 2012 - 293
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