THE RELATION BETWEEN SOIL PH AND THE REPRODUCTIVE/DAMAGE POTENTIAL OF PRATYLENCHUS THORNEI ON GROWTH AND OIL YIELD OF MENTHA SPICATA
Influence of different pH levels on the reproduction and damage potential of Pratylenchus thornei and growth/oil yield of Mentha spicata was studied in pure sand. Growth and oil yield were best at pH 6 followed by pH 3 and 9 respectively in uninoculated plants. Reduction in fresh/dry weight, oil yield, chlorophyll, sugar and phenol content in leaves was directly proportional to pH levels as compared to uninoculated plants. Similarly, final nematode population and reproduction rate of P. thornei was directly proportional to Ph levels. Final nematode populations significantly varied among the pH levels. Influence of P. thornei on all the test parameters was highly significant irrespective of pH levels. Similarly, influence of pH levels on different plant growth parameters was always significant except in the case of plant dry weight between pH 3 and 6.