Table 3.

Summary of knowledge on plant-phytoplasmas-vector interactions.

Location	Disease common name	16S rRNA Subgroup	Vector	Status	Testing method	References
Florida	Lethal yellowing	16SrIV-A	Haplaxius crudus (formally Myndus crudus) [Cixiidae]	Confirmed	Cage transmission tests	Howard et al., 1983; Harrison et al., 2008
Mexico	Lethal yellowing	16SrIV-A	H. crudus	Suggested	Observations	Vázquez-Euán et al., 2011; Córdova et al., 2014
Jamaica	Coconut lethal yellowing	16SrIV	Cedusa spp. [Derbidae]	Putative	PCR and epidemic corresponding with pest outbreaks	Brown et al., 2006
Ghana	Cape St. Paul Wilt	16SrXXII	Myndus adiopodoumensis (Ceotto and Bourgoin, 2008) [Cixiidae] Diostrombus spp. [Derbidae]	Negative Putative	Cage trials One insect detected positive by PCR Cage transmission so far unsuccessful	Philippe et al., 2009 Pilet et al., 2009 Philippe et al., 2009
Mozambique	Coconut lethal yellow syndrome	16SrXXII	Platacantha lutea Westwood, 1837 [Pentatomidae]	Putative	PCR	Dollet et al., 2011
Tanzania	Coconut lethal disease	16SrIV-C	Diastrombus mkurangai Wilson [Derbidae] Meenoplus spp. [Meenoplidae]	Putative	PCR	Mpunami et al., 2000
India	Kerala wilt disease or Root wilt disease*	16SrIV-C Or IX	Stephanitis typica (Distant) [Tingidae] Proutista moesta (Westwood) [Derbidae] Sophonia greeni (Distant) [Nirvanidae]	Positive Positive Putative/ negative	Cage transmission Cage transmission Survey/PCR	Mathen et al., 1987, 1990 Rajan, 2013 Rajan, 2013
Sri Lanka	Weligama coconut leaf wilt disease	16XI	Multiple	Putative	Survey/PCR	Kumara et al., 2015
PNG	Bogia coconut syndrome		Zophiuma pupillata [Lophopidae] Proustia sp. (sic; >Proutista sp.) [Derbidae]	Putative	PCR of whole insect bodies	Pilotti et al., 2014

^*Some papers refer to Kerela wilt disease (KWD) and Root (wilt) disease (RWD), as being synonymous (Howard, 2001b; Sharrnlla et al., 2004), whilst PCR testing has classified KWD as 16SrIV-C (Edwin and Mohankumar, 2007a) and RWD as 16SrIX (Manimekalai et al., 2010). Sharrnlla et al. (2004) referred to “Kerala wilt disease of coconut palms, formerly named as root (wilt) disease” and considered it as a “separate group in the 16Sr classification” but did not indicate which group name. Another paper used PCR analysis and called KWD as closely related to the 16SrIV-C sub-group (Edwin and Mohankumar, 2007a). Manimekalai et al. (2010) reported that a new phytoplasma sub-group was found on diseased coconut palms and referred to the disease as RWD and stated “Our RWD phytoplasma sequence does not match an earlier reported Kerala (wilt) coconut phytoplasma sequence (AY158660) and the latter sequence does not have similarity with any known phytoplasma sequences in the database.” This phytoplasma was declared to be in the 16SrXI group which was also the cause of the sugarcane white leaf phytoplasma also commonly found in India (Manimekalai et al., 2010). This work was confirmed by Manimekalai et al. (2014a) and further sub-grouped into 16SrXI-B by Manimekalai et al. (2014c) who stated “The RWD phytoplasma sequence reported here did not show identity with sequence reported earlier for Kerala wilt coconut phytoplasma (GenBank Acc No AY158660) (from Sharrnlla et al., 2004), and which did not have similarity with any known phytoplasma sequences in the database.” Yadav et al. (2015) states they found 3 possible sub-groups interacting; 16SrXI-B in Kerala, XIV-A in Karnataka and another 16SrXIV in Kerala. Most literature on vectors refers to RWD only. The review paper Ramjegathesh et al. (2012) states that S. typica and P. moesta are both vectors of RWD which is consistent with the website for Central Plantation Crops Research Institute in India where most phytoplasma research is conducted (http://cpcri.gov.in/index.php?option=com_content&view=article&id=117&Itemid=142) however, Edwin and Mohankumar (2007a,b) suggest that S. typica is not a vector of KWD.