Vol. 3, Issue 4 (2018)
Comparative study of diversity and termite damage in the selected variety of cocoa "Mercedes or CNRA" and unselected "Tout venant" grown in Abengourou in eastern Côte d'Ivoire
Author(s): ANO Ehui Joachim, TAHIRI Annick, SIAPO Yao Martin, DIBY Yao Kan Séraphin
Abstract: This work was done in the East of Côte d’Ivoire in Abengourou, in order to compare the termite diversity and their impact on two cultivated cocoa varieties « Mercedes » and « Tout venant ». One hundred (100) of 2-year-old cocoa plants were delineated on three plots by variety of cocoa. The results obtained show a comparatively identical specific richness in the two varieties. The unselected variety "Tout venant" records 18 species against 17 species for the selected variety "Mercedes". The comparison of the specific richness, the Shannon diversity index (H'), the Simpson index (SI) and the Equitability index (E) do not vary significantly between the two varieties of cocao. The density of termites varies significantly depending on the variety in the soil. The densities of the varieties "Mercedes" and "Tout venant" were respectively 2755.50±397.43 ind/ m2 and 1612.37±208.74 ind/ m2. Densities at the depth level were also compared for both varieties. Statistical analyzes show that the "Mercedes or CNRA" variety has the highest density at all depths. This density decreases with the depth of the two varieties. Eleven (11) species of termites have been identified, 8 of which are common to both varieties. The calculated Jaccard coefficient was 0.74. This value does not reflect any difference in the diversity of termites pests in both varieties. The attack rates of the "Mercedes" and "Tout venant" varieties were respectively 25.00 ± 1.15% and 26.33 ± 1.20%. These rates do not vary significantly between the two varieties. The species Ancistrotermes guineensis and Microtermes sp1 are the most aggressive. A. guineensis, with an attack rate of 34.68 ± 1.70 %, is more aggressive on the variety "Mercedes" and Microtermes sp1 on the variety "Tout venant" with an attack rate of 24.74±1.33%. This work shows that the new cocoa variety "Mercedes" does not influence the biodiversity and the attacks of the cocoa pest termites but shows a difference of the termite population in the soil depending on the variety and specificity of the termites pests depending on the species.