SHARMA, G.C.JITENDER, SINGH2016-11-102016-11-102016http://krishikosh.egranth.ac.in/handle/1/84836ABSTRACT The present investigations were carried out on the topic “Population dynamics of plant parasitic nematodes associated with apple orchards in Himachal Pradesh”. Spatial distribution experiments were carried out in apple orchards of three age groups viz., 8-10 year, 13-15 years and 18-20 years, which were located at Reckong Peo (Kinnaur) and Shallang (Kullu). In all, whereas, seven nematodes viz., P. coffeae, H. dihystera, T. mashhoodi, P. curvitatus, Meloidogyne sp., M. xenoplax and Xiphinema sp. were found harbouring the orchards, the foremost nematode (P. coffeae) was most predominant. In 8-15 years age group orchards, 120×15 cm and 90×15 cm combinations, while in 18-20 years old orchard, 120×30 cm combination were found most appropriate sites for estimating status of plant parasitic nematodes. Seasonal fluctuation studies were carried out in 20 years old apple orchard of Regional Horticultural Research and Training Station, Mashobra (Shimla). Results revealed, highest total nematode population in the month of September followed by in October and November and it remained minimum in the month of January. Correlation study between nematode population and abiotic factors (temperature, moisture, pH and organic carbon) have revealed significant negative correlation between organic carbon and population build up of lesion nematode (P. coffeae). However, impact of other abiotic factors on the nematode populations remained non considerable, temperature and moisture showed their positive correlation, while pH and organic carbon were negatively correlated.enorchards, apples, planting, sampling, biological interaction, parasites, marketing, fruits, seasons, soil samplingapple orchards,nematodesThesis