Reducing root galling caused by root knot nematodes in black pepper (<em>Piper nigrum</em> L. cv. ‘Kuching’) through nutrient supplementation

Abstract

Purpose: Root-knot nematodes (RKN) remain one of the leading causes of economic damage in black pepper (Piper nigrum L.) cultivation worldwide. An experiment was conducted to evaluate the response of black pepper plants to RKN when irrigated with three nutrient solutions; Hoagland solution only, Hoagland solution + 0.005 mM potassium silicate solution, and Hoagland solution + 2 mM salicylic acid solution. Research Method: Plants grown in medium-sized polybags were inoculated with RKN and routinely irrigated with the appropriate nutrient solutions. Presence of foliar symptoms of RKN infection on plants, their aerial growth plus root infestation were assessed. Superoxide anion and hydrogen peroxide production from the plant leaves were also detected after inoculation. Findings: Foliar symptoms of RKN infection started manifesting after 81 days from inoculation. Plants without silicate or salicylic acid supplementation displayed the most severe foliar disorder symptoms, highest root galling and the shortest aerial growth. Plants irrigated with potassium silicate had the highest aerial growth and their leaves showed the least oxidative stress when challenged with RKN. Originality: From present results, soil amendment with potassium silicate is a promising tool for reducing root galling and promoting aerial growth in RKN-infested black pepper fields.