S. N. Khan , R. K. Tivari , B. M. Misra , D. S. Rawat

Abstract

Experiments were conducted to evaluate different fungicides against Cladosporium humile J.J. Davis, a serious foliage pathogen of poplars and to study disease development in Shilli Nursery, Solan (H.P.). Dithane M-45(0.35%) was found most effective followed by a mixture of Dithane M-45 and Bavistin (0.2 and 0.05% respectively) and Dithane M-45 (0.25%) Disease development studies revealed that the pathogen overwinters on the fallen leaves, dormant buds, in lenticels and bark crevices of the standing plants. The infection begin to appear on the plants in the month of May and progressed to a highest disease index in November. Measures to control and contain the disease have been suggested.

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M. L. Thakur , Sushil Kumar , Anil Negi , D. S. Rawat

Abstract

Among the exotics, Eucalyptus has emerged as the most favoured species under afforestation programmes in most of the countries where it has been introduced for obtaining higher biomass productivity. However, ischolar_main feeding tel mitts have proved a major constraint for its successful propagation both in nurseries and plantations. Localised tumite damage bas been estimated to result in 50-80 per cent mortality in seedlings and young plantations in some localities. Till recently, the recommendations have been based on bigbly persistent cblorinattd hydrocarbon insecticides, most of which have been banned and are not easily available. In our experiments on the comparative efficacy of various insecticides, chlorpyrifos an organophosphate compound has been found an equally effective insecticide for soil treatment. In the present study, an attfmpt has been made to evaluate various methods of application and the optimum dosage requind for controlling termites in Eucalyptus.

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Sujan Singh , S. N. Khan , B. M. Misra , D. S. Rawat

Abstract

The paper deals with experiments carried out to control Cercoseptoria needle flight of pines in nurseries. Seedlings of Pinus roxburghii, an indigenous pine, and P. greggii, an exotic pine, were used as test species. After screening seven fungicides (dithane M-45, dithane Z-78, cuman L, calixin, bavistin, blitox and karathane) at their prescribed dosages, dithane M-45 and cuman L for P. greggii and dithane Z-78 and calixin along with the above two fungicides for P. roxburghii were selected on the basis of their better performance for testing at higher dosages as none of the seven fungicides effectively controlled the disease at their prescribed dosages. Dithane M-45 and cuman L were found effective at 0.6 per cent concentration in controlling Cercosptoria needle blight on P. greggii in these experiments. On P. roxburghii, however, none of the four fungicides controlled the disease even at highest tested dosages (0.8 per cent except calixin in which case, higher dose was (0.6 per cent). In subsequent experiments where still higher dosages were tested, dithane M-45 and dithane Z-78 effectively controlled the disease on P. roxburghii at 1.0 per cent concentration while in case of calixin the minimal effective dose was found as 0.8 per cent. None of these fungicides had any toxic effect on P. roxburghii seedlings at the higher dosages.

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Pratap Singh , D. S. Rawat , R. M. Misra , Massrat Fasih , G. Prasad , B. D. S. Tyagi

Abstract

no abstract

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G. S. Negi , D. S. Rawat

Abstract

The paper presents the results of a pilot investigation on the size and shape of plots for grass land survey, conducted in Andhra Pradesh. The results based on systematic line plot survey indicate that square or circular plots of 4 square metres may provide equally precise estimates as larger sized plots in such areas. It has been suggested that estimate of grass yield within 10% margin of error may be obtained with a sample of about 70 plots. Systematic sampling with multiple random start has been recommended.

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G. S. Negi , D. S. Rawat

Abstract

The paper presents the estimates of Basal Area from point sampling with prisms of BAF-l, 2, 3, 4 and 5 sq m/hectare and compares them with those from plot sampling with 0.16 hectare plots in a pure sal forest. No significant difference in the estimates of basal area were observed either between the estimates from various prisms or between the two methods of sampling. The relative efficiency of point sampling taking time of cruise into consideration worked out from 200% to 400%, although the estimates from plot sampling were more precise. Prism of Basal Area Factor of 3 sq m/hectare is recommended for similar crops. It has been suggested that to estimate volume with a margin of error of 10% with a prism of BAF-3, about 50 sample points may be needed. However, the same accuracy could also be achieved even if measurements for volume are taken at comparatively lesser number of sample points and basal area which requires less time, estimated from a larger number of sample points.

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