Disease Note.

New Record of a Mycoparasite on Puccinia arachidis in India. P. M. Reddy, Legumes Pathology, International Crops Research Institute for the Semi-Arid Tropics (ICRISAT), Patancheru 502 324, AP, India. . Plant Dis. 73:444. Accepted for publication 14 December 1988. Copyright 1989 The American Phytopathological Society. DOI: 10.1094/PD-73-0444B.

A mycoparasite was observed growing in the uredinia of Piccinia arachidis Speg. on peanuts (Arachis hypogaea L.) at ICRISAT, Patancheru, for four rainy seasons (1985-1988) and in 1986 at Bhavanisagar, Tamil Nadu, India. Infection was evident 60-70 days after sowings, by which time the mycoparasite had colonized approxmately 20% of the uredinia; over 80% of the uredinia were infected at crop harvest. The mycoparasite was cultured on potato-dextrose agar supplemented with groundnut leaf extract (150 ml/L). Conidia from 3-wk-old cultures (1 x 10⁵ conidia per milliliter) were sprayed on rust-infected peanut leaves. The mycoparasite could be observed in the uredinia 6 days later. Scanning electron micrographs of infected uredinia showed growth of the fungus over and into the urediniospores. The fungus was identified as Hyalodendron sp. by D.W Minter (CAB International Mycological Institute [Herb. IMI 312347]). The Hyalodendron sp. has potential for use in biological control of peanut rust because it directly damages the urediniospores and its slimy growth prevents their easy dispersal.