Cixiids and Lethal yellowings of palms, a threatening quarantine disease for Brazil: What we know what could be done?

Coconut palms (Cocos nucifera L.) and other palms can be affected by several types of diseases, mainly by fungi. Palm trees also suffer from vector borne diseases, such as the viral disease Coconut foliar decay transmitted by the cixiid Colvanalia taffini, or the Dry bud rot transmitted by Sogatella kolophon and Chloriona (Sogatella) cubana, Dephacidae. Recilia mica (Cicadellidae) transmits the phytoplasma disease, “Blast”, of coconut and oil palm. But other phytoplasma diseases, the Lethal Yellowing Type Syndromes (LYTS), pose the most serious threat to the sustainability of coconut plantations worldwide and especially in the Caribbean where it is known as Lethal yellowing and considered since 2006 as a re-emerging disease, inducing considerable socio-economic damages. Phytoplasmas are phloem-limited cell wall-less prokaryotes impossible to detect by light microscopy and are unculturable. Most of them are specifically transmitted by planthoppers and leafhoppers. Among the different LYTS known worldwide (at least 4 different phytoplasma species), only one insect vector has been identified so far, in Florida and Mexico. It took around 10 years of intensive search in Florida to succeed in the identification of the vector of LY, the cixiid Haplaxius (Myndus) crudus (Cixiidae). And it is only recently that we could prove the same species was involved in Mexico. However in our experimental transmissions, H. crudus could transmit LYTS to the palm Pritchadia pacifica but not to coconut. This difference in transmission may be related to the existence of different haplotypes which have been highlighted in the Caribbean. Other planthopers could be involved in the transmission, other Haplaxius species or Nyphocixia caribbea or Oecleus species. LY is an absent quarantine pest (A1) for Brazil, and in the same way as the red palm mite Raoiella indica (Tenuipalpidae) or the chikungunya virus invaded Brazil from the Caribbean, LY can invade Brazil anytime. That is why we are trying to implement action plans to, either prevent the introduction of disease, or contain it as soon as it is spotted for the first time. For this purpose we study the establishment of sentinel plantations in Roraima for the detection of potential vectors insects and cases of LYTS. Roraima state was recently invaded by two pests from the Caribbean, because its borders with countries strongly linked with Caribbean countries (Venezuela and Guyana), is a main target of our projects.

Bibliographic Details

Main Authors:	Dollet, Michel, Vieira Teodoro, Adenir, Morais, Elisangela G. F., Diniz, Leandro Eugenio Cardamone, Dzido, Jean-Luc
Format:	conference_item biblioteca
Language:	eng
Published:	EMBRAPA
Online Access:	http://agritrop.cirad.fr/599527/ http://agritrop.cirad.fr/599527/1/599527.pdf
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