Plant parasitic nematodes are considered as one of the major constraints of successful cultivation of black pepper. Damage caused by plant parasitic nematodes depends on population density of nematodes around the rhizosphere of a particular crop. Population fluctuation of plant parasitic nematodes is governed by several biotic and abiotic factors. Among the abiotic factors soil type, soil pH, soil temperature, soil moisture, rainfall etc. are most important. Study on population fluctuation of plant parasitic nematodes in the rhizosphere of black pepper in relation to soil and atmospheric temperature and rainfall was conducted during 2022 at Biswanath College of Agriculture, Biswanath Chariali, Assam. In the present study the month of March-April and September-October appeared to be the most favourable for increasing the nematode population in soil around the rhizosphere of black pepper plants. Two peaks of total nematode population during October and April was observed. Maximum population of all identified plant parasitic nematode genera was observed in the month of October. In the month of October average maximum atmospheric temperature was recorded as 31.22°C, minimum atmospheric temperature 19.46°C, soil temperature 29.14°C and rainfall of 111.2 mm. During winter months, nematode population was found to be decline and least nematode population was recorded in the month of January, when maximum average atmospheric temperature was recorded as 23.36°C, minimum atmospheric temperature 7.98°C, soil temperature 23.1°C and rainfall of 26 mm. The present study evaluated the population fluctuations of plant parasitic nematodes in relation with various weather parameters. The study will help in devising management strategies to reduce the infestation of plant parasitic nematodes in black pepper.

Atmospheric temperature, black pepper, nematode population, plant parasitic nematodes, soil temperature

During the winter months population of all plant parasitic nematode was found to be declined as this period received very little amount of rainfall, which indirectly affects the moisture content of soil. Likewise both soil and atmospheric temperature were found to be decline during this period as low temperature is not favourable for nematode multiplication. Nematode populations were found to be increase significantly due to increase of temperature and rainfall, which is congenial for nematode multiplication. Again during the period of heavy rainfall nematode populations were found to be declined as excessive moisture in soil tends to inhibit the locomotion of nematodes and lack of oxygen in saturated soils also adversely affects nematode populations due to asphyxia. Thus it can be concluded that temperature and rainfall have pronounced effect on population fluctuation of plant parasitic nematodes.

Pranjal Pratim Neog (2023). Effect of some abiotic factors on population fluctuation of plant parasitic nematodes associated with rhizosphere of black pepper. Biological Forum – An International Journal, 15(8): 186-190.