Observations on Moulting of Fourth-Stage Larvae of Paratylenchus Nanus

Abstract

Moulting of fourth-stage larvae of ParatylenchuB nanus was stimulated by apricot root secretion but the activity was lost on boiling. Dormant apricot seedlings did not produce an active secretion. The effect was on the anterior part of the nematode and 1 day in secretion was sufficient to initiate the moult. Five to 10 days after stimulation the larvae became motionless and the moult was complete bout 3 days later. Moulting took place most rapidly at about 20°0 and was not affected by pH between 4 and 7. Moulting but not stimulation was inhibited at temperatures of 25 and 30°0. Shedding of the cuticle differed from exsheathment of trichostrongyle larvae in that no refractile ring formed in the anterior part of the cuticle.