Nematodes and Biological Activity Status of Declining Apple Orchards in Shimla and Sirmaur Districts of Himanchal Pradesh-A Survey

A survey was conducted to determine and compare the population density of bacterial, fungal and actinomycetes and nematodes species status in rhizosphere of declining apple trees from different locations of Shimla and Sirmaur districts of Himachal Pradesh during 2015 and 2016. Based on uniformity in respect of age and growth a total of 20 declining apple orchards were selected in ten blocks (Rohru, Gumma, Jubbal, Kotkhai, Pulbhal, Khara Pather, Malat, Kupvi, Habban and Bog Dhar) of the districts of Shimla and Sirmaur. In the present study total five species of nematodes were identified namely Tylenchorhynchus, Pratylenchus, Xiphinema, Helicotylenchus and Paratylenchus from samples. Highest nematode papulation of Tylenchorhynchus, (787) was recorded from Gumma, Pratylenchus (280) from Pulbahal, Xiphinema (180) from Rohru, Paratylenchus (138) from Habban and Helicotylenchus (182) per 250 g of soil from Pulbahal sites. The total microbial count in rhizosphere revealed that Habban had the highest bacterial count (130.49 × 10⁵ cfu/g soil), fungal pathogens population capable of growth was counted significantly highest (15.33 × 10⁴ cfu/g soil) at Pulbahal and highest actinomycetes count (18.00 × 10² cfu/g soil) in rhizospheric soil sample collected from Rohru.