Diversidade e flutuação populacional de cigarrinhas (hemiptera: auchenorrhyncha) potencialmente vetoras do amarelecimento letal do coqueiro em Alagoas, Brasil

Abstract

The coconut lethal yellowing is a disease that is still absent in Brazil, included in the list of high priority quarantine pests for the country. The disease was registered in countries in America and the Caribbean, with an imminent risk of introduction into the national territory.The causative agent of the disease is the phytoplasma ‘Candidatus Phytoplasma palmae’, a mandatory parasite prokaryotic organism, whose the only insect proven to be a vector in coconut palms (Cocos nucifera L.) are adults of Haplaxius crudus (Hemiptera: Fulgoromorpha: Cixiidae). However, there are suspicions that other planthopper species can also transmit the disease. Given the economic and social importance of coconut cultivation for Brazil, especially in the Northeast, the main producing region, it is necessary to deepen the knowledge about the insects potentially vectoring this disease. In this context, this thesis aimed to: (i) identify and characterize the population dynamics of the main families of leafhoppers potential vectors of lethal yellowing in the Alagoas State (Chapter 1) and (ii) identify and characterize the population dynamics of the main types of leafhoppers of the family Cicadellidae (subfamily Cicadellinae, Gyponinae e Deltocephalinae) (Chapter 2) in a coconut production area in the municipality of São Miguel dos Milagres, in the state of Alagoas and correlate them with climatic variables in the region (temperature and relative humidity, solar radiation, wind speed, dew point temperature and rainfall). The population survey was conducted based on the installation and collection of adhesive traps in the experimental area and in the identification of the planthoppers under a microscope in the laboratory. In the Chapter 1, five families of planthoppers potentially vector of lethal yellowing were identified, whose relative frequencies were: Derbidae (53.7%), Cicadellidae (34.9%), Dictyopharidae (6.3%), Cixiidae (3.8 %) and Delphacidae (1.3%). Planthoppers belonging to the Cixiidae family were positively affected by the increase in air temperature and dew point. The populations of Cicadellidae decreased with increases in wind speed and solar radiation. Populations of Derbidae increased in times with higher relative humidity and rainfall and suffered reductions with the increase in wind speed. In Chapter 2, the genera Gypona, Curtara, Scaphytopius, Erythrogonia, Diedrocephala, Tapajosa, Bucephalogonia, Macugonalia, Oncometopia and Hortensia were identified. Populations of Curtara and Gypona increased with the relative humidity of the air and rainfall and suffered reductions due to higher rates of wind speed and solar radiation. Climatic variables influence the individual populations of Derbidae, Cicadellidae, Dictyopharidae, Cixiidae e Delphacidae families and of the Cicadellinae e Gyponinae subfamilies, potential leafhopper vectors of phytoplasmas in the cultivation of coconut trees in São Miguel dos Milagres, Alagoas. Keywords: Cocos nucifera L., quarantine pest, insect vectors, population dynamics, climatic conditions.