Dynamique Saisonnière de Nedotepa curta (Homoptera, Cicadellidae) et Proutista fritillaris (Homoptera, Derbidae), Potentiels Vecteurs du Phytoplasme de la Maladie du Jaunissement Mortel du Cocotier de Grand-Lahou (Côte d’Ivoire)

En Côte d’Ivoire, le cocotier (Cocos nucifera L.) est essentiellement cultivé sur le littoral ivoirien et constitue la principale culture de rente en assurant des revenus à plus de 20 000 familles. Cependant, la plante est sujette à plusieurs contraintes dont la plus inquiétante actuellement est le jaunissement mortel du cocotier de Grand-Lahou. Ce travail vise à étudier la dynamique saisonnière des potentiels vecteurs du phytoplasme de la maladie du jaunissement mortel du cocotier à Grand-Lahou (Nedotepa curta et Proutista fritillaris). Les insectes ont été collectés avec des pièges à glu, hissés à l’aide d’une corde dans la couronne des cocotiers de deux villages de Grand-Lahou (Badadon et Yaokro), d’octobre 2015 à septembre 2016. Sur ces deux sites, les fluctuations les plus importantes des populations de N. curta et P. fritillaris ont été observées en décembre 2015 et en février 2016. L’analyse de corrélation de Pearson réalisée entre quelques facteurs abiotiques et les fluctuations des populations de ces insectes montre que la température et les fluctuations de ces insectes ne sont pas significativement corrélées. Par contre, il existe une influence hautement significative et négative (r˃-0,7 ; p˂0,0001) de la pluviométrie sur les populations de ces insectes. Une influence significative et négative (r˃-0,7 ; p˂0,005) de l’humidité relative sur ces insectes a été également observée. Les potentiels vecteurs du jaunissement mortel du cocotier de Grand-Lahou pullulent donc au cours des périodes sèches de l’année. La température n’affecte pas le développement de ces insectes alors que la pluviométrie et l’humidité relative diminue leur développement.   In Côte d’Ivoire, the coconut tree (Cocos nucifera L.) is cultivated essentially on the coastline of Côte d'Ivoire. It is one of the main cash crops that provide income to close to 20,000 families. The plant is subject to several constraints of which the most troubling one among them is the coconut lethal yellowing of Grand-Lahou. This paper focuses on the seasonal dynamics of the potentials vectors of phytoplasma of the coconut lethal yellowing of Grand-Lahou (Nedotepa curta and Proutista fritillaris). The insects were collected with traps tights, hoisted with the help of a rope in the crown of the coconut trees of two villages of Grand-Lahou (Badadon and Yaokro), from October 2015 to September 2016. On these two sites, the most important fluctuations of the populations of N. curta and P. fritillaris were observed in December 2015 and in February 2016. The realized Pearson interrelationship analysis between some abiotic factors and the fluctuations of the populations of these insects show that the temperature and the fluctuations of these insects are not correlated meaningfully. On the other hand, there is a highly meaningful and negative influence (r˃-0,7 ; p˂0,0001) of rainfall on the populations of these insects. A meaningful and negative influence (r˃-0,7 ; p˂0,005) of the relative humidity on these insects were also observed. The potentials vectors of the coconut lethal yellowing of Grand-Lahou swarm can be seen during the dry periods of the year. Although the temperature does not affect the development of these insects, the rainfall and the relative humidity decrease their development.&nbsp

Efficiency of four types of beetles traps in rubber plantation in the Southern of Côte d’Ivoire

The current study focuses on different types of beetle’s traps in rubber plantations in the localities of Bongo and Toupah, in the south of Côte d’Ivoire. The objective of this work is to determine the most efficient trap for capturing beetles in these agrosystems. Four trapping methods, namely yellow trap on the ground, yellow trap at height, screen trap and pitfall trap were used in plantations of different ages. The investigation resulted in more captures of beetles from the screen traps with means of 236.5 and 365.5 beetles in Toupah and Bongo, respectively. Pitfall traps captured fewer individuals (22.58 and 39.83 individuals from Toupah and Bongo, respectively). Yellow traps on the ground and height captured more individuals in 1 to 5 years aged plantations. Pitfall traps captured more individuals in 6 to 10 year aged plantations and screen traps captured more beetles in the forests. Beetle’s family richness is higher in screen traps with means of 23.83 and 19 families, whereas the pitfall trap captured the fewest beetles’ families with means of 8.58 and 6.58 families captured from Bongo and Toupah, respectively. Yellow ground traps, yellow height traps and screen traps captured more phytophagous beetles. However, pitfall traps captured more predators and fewer phytophagous. The screen trap appeared as the most effective and most suitable trap against beetles in rubber plantations