Six new species of Helicotylenchus Steiner, 1945 associated with oranamental crops in Rajasthan with notes on known associated species

Six new species of Helicotylenchus Steiner, 1945, from the rhizosphere of Jasmine, China Rose, Marigold, Cotton and Bougainvillea, are being described and illustrated. Helicotylenchus jasminii sp. n. is characterized by having smaller body length and stylet, longer oesophageal glands and also by having rounded stylet knobs. H. rajcolagri sp. n is distinguished in having greater body width, longer tail and rounded stylet knobs. H. samorensis sp. n is distinguished by having small stylet, rounded stylet knobs, greater body width, smaller body and longer tail H. gulabi spa is characterized by having greater body width, smaller body, smaller stylet, longer tail and indistinct head annules. H. crotonii sp.n is characterized by having longer oesophageal glands, greater body width, prominent head sclerotization, conoid tail and rounded stylet knobs. H. brevicaudatus sp.n is well distinguished in possessing shorter body, smaller stylet, distinct head annules and hemispherical to broadly conoid tail.