Metabolic factors of eggplant solanum spp. that affects hosts preference of Leucinodes Orbonalis Guenée (Lepidoptera: Pyralidae) and its implication in hosts- pests relationship

Abstract

Leucinodes Orbonalis appears as the main constrain to Eggplant production. In Cameroon, many varieties of the genus Solanum (Solanaceae) are cultivated and their fruits compositions vary in terms of pH, carbohydrates, proteins, and polyphenols content. We investigated to see if primary and secondary metabolites content in the fruits could influence the preference of attacked due to Leucinodes Orbonalis. The damage due to Leucinodes Orbonalis were compared on two species of two cultivars each. These experimentations were carrying out both in the laboratory and on the field. On "zong", "inerme", "jakatu" and "F1 African beauty" varieties, the pH of the fruits was 5.22, 4.57, 5.4 and 5.02 respectively; the sugar content of the fruits was 6.45 mg/g, 4.79 mg/g, 7.92 mg/g and 7.85 mg/g respectively; the polyphenol content of the fruit was 5.74 mg/g, 6.79 mg/g, 5.26 mg/g and 4.63 mg/g and the protein content of the fruit was 3.02 mg/g, 1.66 mg/g, 4.48 mg/g and 4.25 mg/g respectively. The study on the susceptibility of the species/varieties of Solanum spp. showed that S. melongena var. inerme was the most resistant (with 47.8%) and that S. Aethiopicum var. jakatu, most susceptible (with 79.47%) to attacks due to Leucinodes Orbonalis. The study also showed that total sugars, total proteins and pH value levels were positively and significantly correlated with attacks due to Leucinodes Orbonalis (r=0.97*, r=0.86* and r=0.70* respectively) while the total polyphenols content in the fruits was negatively and significantly correlated with the same attacks due to the same fruit pests (r=0.76*). These informations can be of great importance in the varietal selections by farmers.