In the present study, seven indigenous, widely distributed plants of Meghalaya, namely, Pinus kesiya Royle (Pinaceae), Lantana camara Linn. (Verbenaceae), Litsea cubeba Lour. (Lauraceae), Gaultheria fragrantissima Wall. (Ericaceae), Mikania micrantha Kunth.(Asteraceae), Ambrosia artemisiifolia Linn.(Asteraceae) and Eupatorium riparium Regel (Asteraceae) were screened for their larvicidal and antifeedant activity against fourth instar larvae of the cotton bollworm, Helicoverpa armigera (Hübner) under laboratory conditions. The crude extracts of all the seven plants demonstrated a dose dependent increase in bioactivity. However the bioactivity of four plants namely, L. camara, G. fragrantissima, L. cubeba and P. kesiya was significantly higher (p ≤ 0.05) than the negative (solvent) control and extracts of A. artemisiifolia, E. riparium and M. micarantha. Methanol extract of L. camara caused highest oral toxicity with larval mortality ranging between 27.77% and 53.33% across the test concentration (0.25%, 0.5% and 1% w/v) while extract of G. fragrantissima demonstrated the highest feeding deterrence with reduction in larval feeding by50.92% and 70.61% at 0.1% and 0.5% respectively. Crude extract of L. cubeba leaves demonstrated high oral toxicity and feeding deterrence while extract of the needles of P. kesiya showed moderate level of oral toxicity as well as feeding deterrence at the highest tested concentration. Phytochemical analysis of the extracts of these four plants, revealed the presence of five different classes of phytocompounds each of which is known to have deleterious effect on insect pests.Thus it may be concluded that four out of the seven plants possess insecticidal property and can be further investigated for the development of a potent botanical insecticide.

Agroforestry systems of the hilly regions of the north east are small scale, primitive land use systems, evolving through traditional knowledge requiring very little inputs in terms of irrigation, fertilizers and pesticides. The different components of the agroforestry systems were analyzed for their natural enemy complex through a monthly sampling programme. Maintenance and potential role of natural enemies' complex in various compartments of such systems are discussed in the light of land use practices and holding size.

<p>Meghalaya, also known as ‘abode of clouds’, is a state located in north-eastern part of India, blessed with abundance of water resources. In the last few decades, extensive coal mining in different parts of Meghalaya has caused detrimental changes in the environment, particularly the aquatic systems. Acid and metal loaded effluents (also known as acid mine drainage or AMD), resulting from the exposure of sulphide mineralization to oxidizing conditions from abandoned or active mining areas, are the principal environmental problems today. Sulphate (SO<sub>4</sub><sup>2-</sup>) is a major contaminant and attracts widespread attention as the dominant form of sulphur in coal mining affected aquatic systems. The increased presence of SO<sub>4</sub><sup>2- </sup>in ecosystems affected by mining activities has immense negative environmental and human health effects. Low pH and high heavy metal concentrations have been reported from streams flowing in and around the coal mining area in Meghalaya rendering the water quality to be very poor  and unfit for use as potable water.</p><p>Stable isotopes have emerged as a promising environmental tracer to understand different environmental functions and processes. Valuable information on the sources and processes can be obtained from the stable isotope ratios of chemical elements in environmental samples as the sources and processes influence history of the samples. Stable isotopes analysis combined with hydrochemical analysis enhances our understanding of transformation and environmental fate of different compounds in water bodies and can provide precise information about factors responsible for controlling water chemistry of different water bodies.</p><p>Stable isotopes of sulphur and oxygen combined with hydrochemical parameters were used as a tool for determining origin, transformation and fate of sulphur in AMD affected water bodies in Meghalaya.The study was conducted on two rivers affected by AMD, viz. Myntdu River and Lunar-Lukha River, flowing in the Jaintia Hills region of Meghalaya. The water samples collected are analysed for hydrochemical parameters and stable sulphur and oxygen isotopes (δ<sup>34</sup>S and δ<sup>18</sup>O in aqueous SO<sub>4</sub><sup>2-</sup>). The stable isotopes of sulphur and oxygen were also analysed in the coal samples from the nearby mining areas. The result provided an insight into the transformational processes of sulphur in these two AMD affected rivers and the environmental fate of sulphur.</p>