Ratoon clearing of pineapple With paraquat and roundup glyphosphate
S.A. Lee
Abstract
Pyrite and its oxidation products in an acid sulphate soil
Eswaran, H. and Joseph, K.T.
Abstract
Phytophthora Cinnamomi: A new pathogen on cloves in Peninsular Malaysia
Lee Boun Siew
P. cinnamomi was recently isolated from necrotic root tissues of 2-year old die-back cloves; this being the first record of the fungus on clove plants. Laboratory studies indicated that chlamydospores were freely produced in artificial culture media although sporangia were only sparingly produced in LBA and OMA at 25°C. Sporangial production could be easily induced, however, when culture discs from young colonies were placed in either soil extract, petri solution or distilled water. The ability of the fungus to form oospores with an A1 isolate of P. palmivora from black-pepper indicated that the present isolate belonged to the A2 compatibility type. Results obtained from a series of inoculation studies showed high susceptibility of unripe cocoa and rubber pods as well as avocado seedlings and fruits to the fungus. The importance of these findings in relation to cocoa, rubber and avocado cultivation in Malaysia is briefly discussed.
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Effect of water on growth and nutrient uptake of pineapple
T.H. Tay
Vegetative growth of the Masmerah pineapple responded signi ficantly to increasing levels of watering. In the development of plant height 0.8 cm rainlfall equivalent was optimum while leaf number increment was most responsive with 1.6 cm rainfall equivalent. Increasing frequency of watering was also observed to enhance vegetative growth. Waterlogging was found to affect growth and nutrient uptake adversely.The optimum water-table for pineapple growth was noted to be at 48 cm from the soil surface. Favourable nutrient uptake was observed to occur when the water table was maintained in the range of 30-50 cm from the soil surface . Drought and waterlogging retarded natural flowering while increasing watering frequency was observed to enhance it. With the treatment of 0.8 cm rainfall equivalent, the response to flower induction was better. At the same time it was observed that this water regime was most conducive for natural flowering. The mean fruit weight, lenght and diameter responded significantly to water treatments.The optimum watering level for development of these three parameters was 0.8 cm rainfall equivalent.Watering frequency had no statistically significant effect on mean fruit weight, lenght and diameter.Watering levels and frequency had no statistically significant effect on the first sugar and acid contents.
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Effect of GMV on groundnuts at different growth stages
Gru Swee Lan and Ting Wen Poh