The insecticidal and repellent activity tests of the chloroform extracts of fruit, leaf, root and stem of Urena sinuata L. against the red flour beetle Tribolium castaneum L. adults have been conducted. The leaf, root and stem extracts showed high toxicity by giving mortality of the beetles within 30 min. of exposure. The LD50 values for the 12, 24, 36 and 48h of exposures were 0.354, 0.262, 0.209 and 0.196mg cm2 for the fruit extract; 0.587, 0.413, 0.355 and 0.299mg cm2 for the leaf extract; 0.440, 0.389, 0.340 and 0.268mg cm2 for the root extract and 0.968, 0.661, 0.491 and 0.362mg cm2 for the stem extract. The insecticidal activity can be arranged in the order of fruit> root> leaf> stem extracts. The root and stem showed repellent activity against T. castaneum adults at P<0.01 and P<0.05 levels of significance, while the fruit and the leaf extracts did not show repellency at all. DOI: http://dx.doi.org/10.3329/ujzru.v30i0.10740 Univ. j. zool. Rajshahi Univ. Vol. 30, 2011 pp. 25-28

A study on the physiology of root parasitism in sandal (Santalum album L.) was conducted by comparing a six-year-old sandal grown alone and along with a host (Casuarina equisetifolia). Although maximum haus-torial connections were observed when grown along with the host, sandal formed haustorial connections with plants including grass up to a distance of 3 m. Anatomical studies on haustoria indicated a vascular connectivity between the host and sandal. While the haustoria functioned as a physiological unit supporting nutritional requirements of sandal, direct lumen-lumen xylem connections between sandal and host were absent. Functional status of the haustorial connection was studied by radio-labelling the host (Casuarina) and nearby grass with phosphorus (32 P). Presence of translocated 32 P in sandal was noticed after six hours of labelling the host. 32 P activity was noticed from eight days up to 16 days after which then it started decreasing. Study with multiple hosts revealed that the extent of translocation from hosts to sandal varied from 28.9% (coconut + Casuarina + rubber as host) to 78.5% (Casuarina + rubber as hosts). Reverse translocation of 32 P from sandal to host was also observed. The study concludes that it is not necessary to plant the host along with the sandal as it is practiced presently.