Sensibilité à Mononychellus tanajoa Bondar (Acari : Tetranychidae) de quelques cultivars de manioc (Manihot esculenta Crantz) et incidence des attaques sur le rendement, dans la région des hauts plateaux de l'Ouest Cameroun

Tropicultura

关键词: Cassava;    Mononychellus tanajoa;    Cassava green spider mite;    Damage;    Sensibility;    Mite density;    Yield loss;   

DOI  :  

来源: DOAJ

【 摘 要 】

Sensibility to Mononychellus tanajoa Bondar (Acari : Tetranychidae) of some Cassava (Manihot esculenta Crantz,) Cultivars and Effect of Damage on Yield Loss in the Cameroonian Western High-lands. The study of the sensibility towards the green mite Mononychellus tanajoa Bondar of some cassava (Manihot esculenta Crantz) cultivars and the assessment of the effect of damage on the yield losses was carried out in the Western highlands of Cameroon. Four cassava cultivars were used : two local (Dschang and Njombe) and two improved varieties (IITA 8017 and IITA 82516). The results obtained showed that the density (mites number/cm2 of leaf area) was low during the rainy season and high during the dry season, which means that rains reduce the mite population by washing or lead the mites to death. The highest mean density (3.40 mites/cm2 of leaf area) was obtained on the local Njombe cultivar which is consequently the most sensitive. On the contrary, the local Dschang cultivar, with the lowest mite density (1.40 mites/cm2 of leaf area) was the most resistant followed by the IITA 8017 cultivar (1.74 mites/cm2). The IITA82516 cultivar had a mean density of2.65 mites/cm2. Yield losses ranged from 36.90 % for IITA 8017 (1.74 mites/cm2 and damages level of 2.75) to 58.70 % for local Dschang (3.40 mites/cm2 and damages level of 3.84). Local Dschang cultivar (1.40 mites/cm2 and damage level of 2.96) and IITA 82516 (2.65 mites/cm2 and damage level of 2.96) had a yield losse of38.10 % and 41.80 %. The results showed that higher the mite density and damage level are, higher is the yield loss, unless the cultivar is tolerant.

【 授权许可】

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