Effects of Phytolacca dodecandra Extracts on the Quality Parameters of Stored Maize Grains

Abstract

Objective: subsistence farmers in Mbulu district to control grain pests in stores use Phytolacca dodecandra leaves. The study evaluated the effects of leaf and root extracts of P. dodecandra on grain quality: moisture content, insect infestation, seeds germination, colour and odour over 150 days of storage.
Methodology and Results: P. dodecandra plants were collected, identified, processed and extracted using ethanol (95% v/v) and extracts stored at -4 °C for quality tests. Synthetic pesticide (Actellic goldTM dust) at 0.05 g/kg and untreated maize sample were used as positive and negative controls, respectively. No significant increase of moisture content (p <0.05) was observed in treated maize compared to controls. Leaf and root extracts minimized grain damage to <5% and <6%, respectively after 150 days post treatment. Both extracts did not affect odour, though leaf extracts affected grains colour. Both extracts insignificantly reduced seed germination index (p > 0.05) to 29%.
Conclusion and Application of findings: P. dodecandra extracts have little impact on the moisture content of the stored maize grains. Germination index of the treated maize was affected neither by the extracts nor by the storage duration up to 150 days. These marginal changes in grains moisture, odour and colour have no significant impact on the local market value of the maize grains. P. dodecandra extracts for use as biopesticide are recommended as a sustainable alternative to synthetic pesticides in maize grains storage especially for the subsistence farmers. However, further tests on biosafety and effects of the extracts on the organoleptic contents of the grains prior to consumption are recommended.