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M. A. Ram Reddy , S. N. Khan , N. D. Dobriyal

Abstract

The effect of mineral fertilizers and compost of the development of mycorrhiza in chir pine (Pinus roxburghii Sargent), an indigenous slow-growing pine and patula pine (P. patula Schlecht and Cham,) an exotic fast growing pine in India was studied. The effects or fertilizers and compost varied with the plant species, In chir pine, application of compost had better effect of plant growth except for reduction of short ischolar_mains but application of fertilizers reduced plant growth as well as short ischolar_mains. On the other hand, addition of compost had no effect on plant growth in patula pine but plant growth increases were directJy proportional to the dosages of NPK fertilizers. Both compost and fertilizers had no effect on short ischolar_main production. In both the species, mycorrhizal development was retarded by application of compost and high dosages of mineral fertilizers.

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B. K. Bakshi , M. A. Ram Reddy , Sujan Singh , P. C. Pandey , S. N. Mukherjee

Abstract

In plantations in the Siwalik Forest Division, U.P. State, raised on site previously occupied by scrub forests, khair seedlings suffered a mortality of 14 per cent, of which 12 per cent could be ascribed due to attack by the ischolar_main parasite, Ganoderma lucidum (Leyss.) Karst. The fungus, as endemic species in the natural forests, built up in the residual stumps which served as infection centres of high inoculum potential. The decayed stumps infected khair seedlings by direct ischolar_main contact and killed them. Removal of residual stumps and ischolar_mains from trenches prior to planting in order to remove the source of infection will bring the disease incidence to the minimum.

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M. A. Ram Reddy

Abstract

In India, plantations of indigenous species of conifers are raised on a large scale and also those of exotics on trial basis. The planting stock is raised in the nursery in which mortality soon after germination, popularly known as damping-off disease, is serious. Symptoms of damping-oft, causal organisms and the extent of damage in some nurseries are described. Control measures outlined include cultural practices in which the nursery soil should have light texture and acid pH (4.5) and through use of chemicas such as Thiram 75% W.P. (Tetramethyl thiram di-Sulphide) is recomened.

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B. K. Bakshi , M. A. Ram Reddy , Balwant Singh

Abstract

A serious butt and trunk rot in living deodar (Cadrus dendara Loudon) was recorded in a pure deodar plantation clear fel1ed in 1967 in Aleo Bihal, Manali, Kulu Forest Division, H.P. State. About 56 per cent trees and 24 per cent stumpage area showed decay. In ischolar_mains located in between boulders, cracks may have appeared due to inadequate space during their development. The decay fungus possibly entered through such injuries. Sporophores associated with decay could not be seen on fresh deodar stumps on the site clear felled in 1967 or old stumps on a similar site clear felled in 1935. The decay fungus was isolated in culture and described. In cultures, perfect fruiting bodies developed from which the fungus could be identified as Peviaphara luna Romell. The sporophores of this fungus produced in nature are present in the herbarium and were collected during earlier years on associated deodar logs showing brown, cuboidal decay. The significence of decay in deodar in cross cutting of logs to different sizes eliminating the decayed portions and also in the healthy growth of trees replanted on such bouldery sites are discussed.

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M. A. Ram Reddy , B. M. Misra

Abstract

Nine chemicals including two highly phytotoxic and seven relatively non-phytotoxic ones are screened to study their effectiveness in the control of damping-off diseases, using three Pinus species. Except for brassicol and zinc oxide, a1l other chemicals effectively checked the disease. However, only blitox, zineb and cuman controlled the disease and thereby signlficantly increased the number of seedlings. Formalin, sulphuric acid, captan and thiram controlled the disease effectively. However, these chemicals decreased germination possibly due to phytotoxic effect of dosages of chemicals and this resulted in reduced number of seedlings. Pinus insularis was found to be more susceptible to damping-off than the other two species. The incidence of damping-off in the three different species differed on soils differently treated.

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B. K. Bakshi , M. A. Ram Reddy , Sujan Singh , P. C. Pandey

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Two damaging stem diseases on exotics are reported. They are the pink disease due to Corticium salmonicolor resulting in over 50 per cent mortality in 2-5 year plantations of Eucalyptus globulus in North Bengal. The fungus is also responsible for the serious twig blight in Populus casale, Casuarina montana and Podocarpus glacilior at New Forest, Dehra Dun. A serious oozing canker on stems and branches resulting in die back on 3 species of exotic cypress (Cupressus arizonica. C lusitanica and C. sempervirens) and Juniper (Jumperus procera) in New Forest is caused by Monochaetia unicornis, a new record in India. The causal organisms, hosts attacked, damage, factors predisposing plants to attack by the pathogens and control measures are described.

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M. A. Ram Reddy , R. K. Tewari , B. K. Bakshi

Abstract

At the Institute campus, plantations of Rauvolfia serpentina (Linn.) Benth. ex Kurz, a herbaceous crop of medicinal importance, suffered heavily from a leaf spot disease, caused by Corynespora cassiicola (Berk. & Curt.) Wei, whose pathogenicity was proved by inoculation experiments. Following initial screening of fungicides, fixing the dosage to be used and time of application as to whether they should be applied as prophylactic or curative, field trials were conducted using chemicals at 0.25% solution in water as prophylactic sprays applied six times at monthly intervals from June to November. Of the 4 fungicides tested in the field, only Captan proved effective in controlling the leaf spot disease resulting in significant increase in ischolar_main yield. The net increase in ischolar_main yield per acre in terms of money value was found to be about Rs. 85, Rs. 601 and Rs. 2,222 at the end of first, second and third year respectively.

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B. K. Bakshi , M. A. Ram Reddy , H. S. Thapar , S. N. Khan

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The problems of natural and artificial regeneration in fir, Abies pindrow Royle are discussed. The factors inimical to natural reproduction are reviewed. Field studies indicate that deep raw humus, large stand openings, and grazing are some of the important factors contributing to the failure of natural regeneration. In deep humus, the regeneration fails to establish because of poor development of ischolar_mains and mycorrhiza. Few seedlings which survive the initial years develop good ischolar_mains and mycorrhiza when the ischolar_mains reach the mineral soil beneath. Due to difficulties in natural regeneration, artificial regeneration of fir forests is engaging active attention. In the fir zone, seedlings require 3½-years to reach the transplantable height of about 22 cm. To reduce the period of growth in the nursery, it was thought that low attitude nurseries might be helpful. Results of studies conducted in one such nursery at Shamshi (H.P.) are given, and show that germination could be increased and seedling mortality could be controlled through fungicidal seed treatment. However the height growth could not be improved even after soil acidification and introduction of mycorrhiza, due possibly to the inherent slow growth in fir and also because the soil pH which was lowered by acidification did not get stabilized due to high free calcium carbonate in the soil. Seedlings with mycorrhizal ischolar_mains were healthier with green lusture and showed increase in dry weight over the control. Future line of work for the low altitude fir nurseries includes selection of suitable site with acid soils or containing low free calcium carbonate, selection of suitable seed provenance fortification of seedlings with mycorrhiza and stimulating height growth by using growth regulators.

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M. A. Ram Reddy , P. C. Pandey

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Cercospora pini-densiflorae Hori et Nambu recorded on 5-6 year old radiata pine for the first time in India at Amarkantak, M.P. state, is described. The pathogen causes serious needle blight and mortality of branches and plants. The disease is severe on young plants and may be controlled by spraying with 0.2 per cent copper based fungicide at fortnightly intervals.

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