The chlorite-group mineral chamosite occurs in nanocrystalline form (~200 nm grain size) as a naturally occurring clay in the Quaternary marine sedimentary deposits near Kudiamozhi, Tuticorin District, Tamil Nadu, India; samples were used in this study as a reusable catalyst. The clay has the usual alternating tetrahedral-octahedral-tetrahedral silicate/aluminate/silicate layer structural arrangement (sometimes called the 2:1 silicate or talc layer structure). The interlayer and the t-o-t layer are bound together by both electrostatic and hydrogen-bonding forces. This natural clay catalyst has been well characterized by various techniques such as Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), X-ray diffraction (XRD), temperature programmed desorption (TPD), thermal analysis and BET surface area measurements (Sreedhar et al., 2009); it has been utilized for various organic transformations such as acylation of alcohols and amines, cyclization of arylaldehydes with O-phenylenediamines and C-O bond formation reactions.

The incidence of the American serpentine leafminer, Liriomyza trifolii (Burgess) (Diptera: Agromyzidae) was studied in cotton-growing tracts of Tamil Nadu State, India. The incidence was higher on summer than on winter cotton and the cropping pattern was found to have an impact on the incidence of the leafminer on cotton. Biological studies on L. trifolii conducted on cotton, Gossypium hirsutum L., tomato, Lycopersicon esculentum Mill., and cowpea, Vigna sinensis (L.) Walp., revealed that its life cycle varied with different hosts. The duration of the pupal stage of L. trifolii was the longest in the leafminer's life cycle. Lycopersicon esculentum was the preferred host—females of L. trifolii survived the longest and had the highest fecundity on this host. Sex discrimination was possible at the pupal stage, on the basis of size; female adults were found to emerge from larger-sized pupae and males from smaller ones.