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INFLUENCE OF CLIMATE CHANGE ON RUBBER HONEY PRODUCTION S. Devanesan, K.S. Premila and K.K. Shailaja AICRP on Honey Bees and Pollinators, Department of Agrl. Entomology, College of Agriculture, Vellayani, Kerala Agricultural University- 695 522, Kerala, India Received: 20 February 2011 Accepted: 11 May 2011 Devanesan, S., Premila, K.S. and Shailaja, K.K. (2011). Influence of climate change on rubber honey production, Natural Rubber Research, 24 (1): 170-173. Apiculture and commercial honey production in Kerala mainly depend on the rubber plantations. Rubber, Hevea brasiliensis Muell Arg. yields both latex and honey (nectar). The latex is produced by the laticeferous cells in the bark and nectar exuded from the extra-floral nectaries at the junction of the trifoliate leaf petiole. The leaves of rubber tree shed during December-January. Generally the shedding of older leaves commences in the Northern parts of Kerala during December and extends up to January in Southern parts. After this, refoliation starts almost within one or two weeks depending on the weather conditions. The occurrence of rainfall during these period results in the infection of tender leaves Oidium causing leaf shedding, affecting seriously the nectar secretion. The young leaves at half maturity (light green colour) secrete nectar through extra-floral nectaries situated at the junction of the petiole. The honey flow begins in Northern districts of Kerala during January- February months and it extends up to February- March in Southern districts. A study was conducted by AICRP on Honey bees and Pollinators at Vellayani centre to correlate the influence of untimely rainfall and honey yield in rubber. Weather conditions influenced the secretion of nectar from the extra floral nectaries. Rain washes away or diluted the nectar from the leaves resulting in severe economic loss to the beekeepers. The increased relative humidity during the refoliation period due to untimely rainfall paved way for the incidence of powdery mildew (Oidium heveae Steinm) on tender leaves. The leaves showed powdery/ashy coating, curling, crinkling and edges of leaves rolled inwards resulting in leaf fall within a week. The average honey yield and data on summer rain for the last five years showed that the untimely rainfall in 2008 honey flow season negatively affected honey yield. The secretion of extra floral nectaries and in turn the production of honey from the rubber plant are related to the prevailing weather and climate change especially too much rains during the nectar secreting season will be harmful for honey production. Keywords: Climate, Honey production, Nectar, Powdery mildew, Refoliation.
IMPACT OF CLIMATE CHANGE ON INSECT PESTS, PATHOGENS AND THEIR NATURAL ENEMIES Suseelendra Desai and M. Srinivasa Rao Central Research Institute for Dryland Agriculture, Santoshnagar, Hyderabad 500059, Andhra Pradesh, India Received: 28 January 2011 Accepted: 27 May 2011 Desai, S. and Rao, M.S. (2011). Impact of climate change on insect pests, pathogens and their natural enemies. Natural Rubber Research, 24(1): 174-186. Climate variability and climate change are exerting additional load on developing countries of tropics and subtropics which are already burdened with the increasing demand for food owing to increasing population pressure. Even a small rise in temperature in these areas will cause significant yield decline in major food grain crops. The changing climate not only influences the crop growth and development but is also expected to alter stages and rates of development of the pathogen, modify host resistance, and change in the physiology of host-pathogen interactions. It is expected that the range of many insects, diseases and weeds will expand or change, and new combinations of pests and diseases may emerge when natural ecosystems respond to altered temperature and precipitation profiles. Although, the research in establishing the climate change impacts on pathogens and their natural enemies is at its infancy, independent studies conducted across laboratories world wide could be used to draw inferences. Elevated CO 2 levels are known to increase foliar density which in turn will influence the microclimate of the pathogen, altered host morphology which affects host-pathogen interaction, enhanced sporulation of pathogen, and increased dry-root rot under moisture stress conditions. For instance, an increase in temperature may lead to increased host susceptibility, a new/rapid development of the pathogen, more rapid vector development leading to faster spread of the vector transmitted viral diseases, a variable overwintering/over-summering of the pathogen/vector and shift in spread pattern of the pathogens. Initial studies show an increased sporulation and altered bio-control traits in Trichoderma, a known bio-control agent. Efforts are underway at CRIDA and other research organizations to assess climate change impact on important pathogens and their natural enemies. The present paper reviews the interaction of weather variables with different insects, diseases and weeds and the probable threats to food grain production, availability and quality. Keywords: Climate change, Climate variability, Insect-pests, Natural enemies, Plant pathogens.
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