4 research outputs found
Characterization of the Probing and Feeding Behavior of Planococcus citri (Hemiptera: Pseudococcidae) on Grapevine
18 páginas, figuras y tablas estadÃsticasThe citrus mealybug, Planococcus citri (Risso) (Hemiptera: Pseudococcidae), is a vector
of Grapevine leafroll-associated virus 3 (GLRaV-3), which causes severe damage to grapevines (Vitis
spp.) worldwide. We studied the feeding behavior of P. citri on grapevine leaves and whole plants
infected with GLRaV-3 and on artiÞcial feeding membranes using DC-electrical penetration graphs
(EPGs). P. citri ingested from phloem sieve elements, but it also spent long intervals in the xylem.
Waveforms, not described before for mealybugs, were characterized, some of them resembling those
of aphids: 1) one new pattern occurring within the phloem phase, named E23, correlated with
honeydew excretion and positive ninhydrine reaction and therefore was associated with sap ingestion
from the phloem sieve elements; and 2) an extracellular waveform, named G, also possibly associated
with ingestion in artiÞcial membranes, which probably represented xylem ingestion. The potential
drops (pd) of P. citri showed two distinct phases (pd1 and pd2).Theoccurrence of pds was, on average,
less frequent than in aphids (0.14/min), but they lasted much longer (32.5 s). The temporal analysis
of 20 EPG recordings on detached leaves lasting 20 h showed great variability among individuals. Only
11/20 mealybugs reached the phloem phase, and ingestion from the phloem sieve elements (E23) was
the predominant phloem-related activity. However, the G pattern was even more frequent, and most
insects (16/20) showed xylem ingestion activities with an average duration of 8.7 h. This work
represents the Þrst step to identify speciÞc stylet activities associated with the acquisition and
inoculation of GLRaV-3 by P. citri.Fundacion Caixa Galicia. This project
was supported by the Spanish Ministry of Education and
Science (AGL2005-01449/AGR).Peer reviewe