Brevipalpus mites (Acari: Tenuipalpidae): vectors of invasive, non-systemic cytoplasmic and nuclear viruses in plants

Abstract

Multi-directional interactions occur among plant hosts, Brevipalpus mites and the plant viruses they transmit. Such interactions should be considered when evaluating the severity of a disease such as citrus leprosis. The current understanding of Brevipalpus-transmitted viruses relies on the capability of the vector to transmit the disease, the persistence of the virus in the host plant and the ability of the disease to spread. Previously, we discussed the Citrus leprosis virus (CiLV) and its importance and spread over the past decade into new areas of South and Central America, most recently into southern Mexico and Belize. Here, we address key questions to better understand the biology of the mite vector, fitness costs, and the peculiarities of Brevipalpus mite reproduction, virus survival, transmissibility and spread, and the expansion of the host plant range of Brevipalpus species vectoring the disease.

Fig. 1

Occurrence of males (a left, b on top) Brevipalpus phoenicis guarding an immature female teleiochrysalis and c mating occurred following the emergence of the adult female

Fig. 2

Paedogenesis occurring in a nymphal stage of Brevipalpus phoenicis. This was first reported by Baker (1972). Some B. phoenicis colonies maintained in the laboratory exhibited occasional events of paedogenesis

Fig. 3

Symptoms of both the cytoplasmatic form of citrus leprosis (left, CiLV-C) and the nuclear form (right, CiLV-N) in sweet orange leaves. Symptoms of the N type of citrus leprosis were usually smaller than those of the C type. Also, the C type of citrus leprosis had an intense yellow margin around the chlorotic lesion

Fig. 4

SEM image showing the moment an adult Brevipalpus phoenicis is piercing a citrus leaf. Both mite palpi are aligned to guide the stylets into the plant tissue

Fig. 5

a Sweet orange orchard showing initial symptoms of leprosis. b The following year the same trees had severe dieback, premature leaf and fruit drop caused by citrus leprosis. c Symptomatic damage by the disease to fruits and leaves that occurred in the Artur Nogueira municipality, SP, Brazil

Fig. 6

Microbial pathogens are major natural enemies suppressing Brevipalpus populations. Metarhizium is one of the fungi reported to infect B. phoenicis as shown in (a) (Magalhães et al. 2005). SEM (b) shows fungal hyphae (arrow) growing between the opisthosomal plates