Description of a new and two known species of Cephaloboides Rahm, 1928 (Nematoda: Rhabditidae) from India, with discussion on the taxonomy of the genus.

A new species of Rhabditidae, collected from manure, is described and illustrated. Cephaloboides anisospiculus sp. n., an amphimictic species with a 1:1 sex ratio, is characterized by a small to medium-sized body (female: L = 0.5-0.7 mm, a = 13.6-20.0, b = 2.7-3.6, c = 15.4-22.7, c' = 1.0-1.8, V = 51.2-60.9), finely striated, punctated cuticle; slightly raised labial papillae; stoma with slightly anisomorphic metastegostom; presence of epiptygma; eggs measuring 37-42 x 20-24 µm; slightly protruded vulval lips with cuticular flaps; rectum 16-19 µm long; males with small, stout, slightly arcuate spicules with hood-like capitula and genital papillae in 1/2/(1+3)+2+P configuration; bursa leptoderan, greatly reduced and not enveloping the caudal spike. C. curvicaudatus (Schneider, 1866) Zullini, 1982 is also redescribed, with an emended diagnosis. The present population of C. curvicaudatus shows a few minor differences viz., relatively smaller 'b' value, presence of elongate capitula of spicules and strong copulatory muscle bands. Another species, C. parapapillosus (Schuurmans Stekhoven, 1951) comb. n. has been reinstated.

Amendment with peony root bark improves the biocontrol efficacy of Trichoderma harzianum against Rhizoctonia solani.

We tested Trichoderma harzianum as a biocontrol agent for Rhizoctonia solani AG2-1, using six natural antifungal materials to improve its efficacy. Among the six materials tested, peony (Paeonia suffruticosa) root bark (PRB) showed the strongest antifungal activity against R. solani AG2-1, and was not antagonistic to T. harzianum. Scanning electron microscopy showed that treatment with PRB extract resulted in shortened and deformed R. solani AG2-1 hyphal cells. The control of radish damping-off caused by R. solani AG2-1 was greatly increased by combined treatments of T. harzianum and PRB, as compared with either of the two treatments alone, with the control effect increased from 42.3-51.5% to 71.4-87.6%. The antifungal compound in PRB, which was isolated in chloroform and identified as paeonol by mass spectrometry, 1H NMR, and 13C NMR analyses, inhibited the growth of R. solani AG2-1 but not that of T. harzianum. Thus, PRB powder or extract may be used as a safe additive to T. harzianum to improve the control of the soil borne diseases caused by R. solani AG2-1.