Studies on Foliage Dieses of Poplars

Symptoms of poplar diseases caused by five major foliage pathogens namely Phyllosticta adjuncta. Myrothecium roridum. Sclerotium rolfsii. Sphaceloma populi and Alternaria alternata are described in this paper. Field observations indicate that P. adjuncta, M. roridum and to some extent S. populi remained on poplar plants in nurseries for longest time while attack of S. rolfsii and A. alternata is confined to lower leaves during monsoon peiod only. Nursery bed with old infected leaves significantly increase the incidence of foliage diseases on paplar plants as compared to beds Cree Crom old leaves. Out of 19 clones of Populus deltoides and 3 of P × euramericana tested for their field resistance against foliage diseases, Done Is found resistant. However attack of foliage pathogens on clones 0-121, G-48, 0-153, G-3 and 6351 of P. Deltoides are significantly less than other clones and hence may be classed as moderately resistance clones. P. deltoides clones, IC, 65/27, 0-100, 6244 and 69/65 are found susceptible and the remaining cIones (Clones 6330, PC-75/6421, 3672, 6358, 6408, 3368, 3231, 2670 and 3196 of P. deltoides and clones 45/51, I-214 and Carppaccio of P. × euramericana ) are highly suceptible to foliage diseases. Out of five fungicides namely captaf, dithane M-45, capptacol, blitox and bavistin screened in the laboratory by poisoned food technique. Bavistin at 0.05 per cent (a. i.) and dithane M-45 at 0.25 per cent (a.i.) are effective against both P. adjuncta and M. roridum .