Botanical Leaf Extracts and Mulching Materials in Organic Eggplant (Solanum Melongena L.) Off Season Production

Abstract

The extensive use of pesticides and the risk they pose to human and the environment requires safe alternatives in crop production hence the study on the efficacy of botanical leaf extracts and mulching materials in organic eggplant production. This study determined the best level combination of botanical leaf extracts that has repellent and knockdown effects on major eggplant insect pest, best level combination of botanical leaf extracts that produces the highest marketable yield; best mulching materials; best level combination of botanical leaf extracts and mulching; correlation of infestation to yield; profitability of eggplant production using botanical leaf extracts and mulching materials combined; and evaluate the effects of botanical leaf extracts and mulching materials on soil chemical properties. A Bioassay test on the botanical leaf extracts was conducted prior to field experiment. Mass rearing the test insects was done to ensure uniform number of insect in eggplant per treatment. A Split- plot in Factorial Design was used in the study with three blocks. The main plot were the leaf extracts of Neem, Madre de Cacao+ Guava at 1:1:1 ratio were: P0 – No Application, P1 –250 ml leaf extract/16 li water, P2 –500 ml leaf extract /16 li water, P3 –750 ml leaf extract /16 li water, P4 – 40 ml Commercial insecticide/16 li water. The sub-plot was: M1 – Black Plastic mulch, M2 – Carbonize Rice Hulls, and M3 – Saw Dust. Results of the bioassay showed highly significant knockdown effect in the application of 500-750ml leaf extract/16 li water on fruit and shoot borer, lady spotted beetle and white flies comparable to application of commercial insecticide/16 li water. Significant repellent effects on Fruit Shoot Borer and Lady spotted beetles but no repellent effects on white flies for an application of 250ml botanical leaf extracts/16li water. Results under field condition showed that plants applied with 750ml botanical leaf extracts/16 li water is more effective than commercial insecticide/16 li water in reducing damaged leaves during the early vegetative stage of development (2nd WAT) and at reproductive stage of development (10th WAT). Highly significant difference was obtained in terms in weight of non-marketable fruit. No significant interaction was registered between botanical leaf extracts and mulching materials. Regression correlation analysis revealed that there was a direct correlation between the numbers of damaged leaves to yield. Combined application of botanical leaf extracts at 750ml/16 li water + carbonized rice hulls obtained Php 797,635.15 net for organic off-season eggplant production. Soil pH, OM, P, and K were increased with application of sawdust, carbonized rice hulls and plastic mulch.