EFFECT OF FARMING PRACTICES AND FARM HISTORY ON INCIDENCE OF COCONUT LETHAL YELLOWING IN MOZAMBIQUE

Management of coconut ( Cocos nucifera ) lethal yellowing disease (CLYD), which has killed about eight million coconut trees in Mozambique, has proved challenging. The objective of this study was to investigate the impact of farming practices and related history, on the CLYD incidence in Mozambique. The methodology included a socioeconomic questionnaire to the households and direct observations on the palm farms. The collected data were analysed using logistic regression. Five out of 11 explanatory variables tested, namely farm age, availability of other palm species on the coconut farm, type of coconut varieties grown, root cut practices, and intercropping had a significant (P< 0.05) effect on CLYD incidence. Coconut farms <10 years had higher odds of higher disease incidence compared to the farms between 10 to 40 years old. The presence of other palm species in the coconut farms had two times higher odds of having higher disease incidence levels compared to farms without other palm species. Tall coconut varieties were likely to be more tolerant to CLYD compared to dwarf varieties. Coconut farms with some kind of intercropping had two times higher odds of having higher disease incidence levels compared to pure stands. The practice of cutting coconut roots had three times higher odds of having high disease incidence levels compared to non-practicing farms. Farm age, availability of other palm species on the coconut farm, type of coconut varieties grown, root cut practices and intercropping need to be considered for integrated CLYD management.La lutte contre la maladie de jaunisse l\ue9tale (CLYD) du cocotier ( Cocos nucifera ), qui a d\ue9cim\ue9 pr\ue8s de huit millions de cocotiers au Mozanbique, n\u2019est pas ais\ue9e. L\u2019objectif de cette \ue9tude \ue9tait d\u2019\ue9valuer les impacts des pratiques culturales et leur histoire, sur le l\u2019incidence de CLYD au Mozambique. Une enqu\ueate socio\ue9-conomique a \ue9t\ue9 administr\ue9e aux m\ue9nages et des observations directes dans les champs de cocotiers ont \ue9t\ue9 r\ue9alis\ue9es. Les donn\ue9es collect\ue9es ont \ue9t\ue9 analys\ue9es par r\ue9gression logistique. Cinq des onze variables explicatives, \ue0 savoir l\u2019\ue2ge de la plantation, la presence ou non d\u2019autres esp\ue8ces de palmiers sur la plantation, le vari\ue9t\ue9 de cocotiers plant\ue9s, la pratique d\u2019\ue9lagage racinaire et la pratique d\u2019association des cultures avaient des effets significatifs (P< 0.05) sur l\u2019incidence de CLYD. Les plantations vieilles de plus de 10 ans pr\ue9sentaient plus de signes de l\u2019incidence de la maladie que les plantations plus vieilles entre 10 et 40 ans. La pr\ue9sence d\u2019autres esp\ue8ces de palmiers dans la cocoteraie causaient deux fois plus de signes d\u2019incidence de la maladie, compar\ue9e aux cocoteraies ne comportant pas d\u2019autres esp\ue8ces de palmiers. Les vari\ue9t\ue9s de grands cocotiers ont tendance \ue0 mieux tol\ue9rer le CLYD, compar\ue9 aux vari\ue9t\ue9s courtes. Les cocoteraies avec association d\u2019autres cultures pr\ue9sentaient deux fois plus de signes de maladies que les cocoteraies simples. La pratique d\u2019\ue9lagage racinaire pr\ue9sentait trois fois plus de signe d\u2019incidence de la maladie. Au total, l\u2019\ue2ge, la presence ou non d\u2019autres esp\ue8ces de palmiers, la vari\ue9t\ue9 de cocotiers produite, les pratique d\u2019\ue9lagage racinaire, et l\u2019association d\u2019autres cultures avec les cocotiers sont \ue0 considerer dans pour une lutte int\ue9gr\ue9e contre CLYD

\u2018Candidatus Phytoplasma palmicola\u2019 and Tanzanian lethal decline phytoplasma detection in the Derbidae Diastrombus mukurangai in Mozambique

revealed that Diastrombus mukurungai is a potential vector of the coconut phytoplasmas in Mozambique. Furthermore, the results revealed that Diastrombus mukurungai was harbouring two different phytoplasmas types: \u2018Candidatus Phytoplasma palmicola\u2019 (16SrXXII-A), and and a strain that was previously isolated in Tanzania. The results also confirm the occurrence of \u2018Ca. Phytoplasma cocostanzaniae\u2019 in Mozambique. This is the first report associating D. mukurungai with \u2018Ca. Phytoplasma palmicola\u2019 in the world. Moreover the results also revealed slightly higher diversity of phytoplasmas species associated with Diastrombus mukurungai in Mozambique than previously found. Further research is underway to increase our knowledge about the vectors of the CLYD phytoplasmas in Mozambique