Experiments were conducted to assess the effect of four plant growth regulators (PGRs), namely coumarin, kinetin, gibberellic acid (GA3) and indole-3-acetic acid (IAA), on the development of the melon fruit fly, Bactrocera cucurbitae (Coquillett) (Diptera: Tephritidae). All four compounds exerted growth-and development-inhibitory effects on the fly. Coumarin was most potent, followed by kinetin, GA3 and IAA. The first and second instars of the fly were more sensitive than the third instar. Treatment with the PGRs also prolonged the fly's developmental period, reduced percentage emergence and increased percentage of abnormal flies emerging. At the higher concentrations tested (125, 625 and 3125 µg/ml) coumarin, kinetin and GA3 caused 100% mortality in first instars.

Introduction. Cytokinins enhance axillary shoots, which helps prolific shoot multiplication in vitro. Very few reports are available on biochemical changes associated with this in vitro proliferation of Citrus. The present study was undertaken to find out the influence of two widely used cytokinins on various morphological and biochemical constituents of in vitro proliferated shoots of Citrus species. Materials and methods. Shoots of (0.5 to 1.0) cm long from in vitro proliferated shoots of five Citrus species were cultured on MS medium supplemented with eight increasing levels of benzylaminopurine (BAP) or kinetin spread from (0.25 to 2) mg$\cdot$L-1. After 6 weeks of culture, morphogenetic characters were observed, and shoot samples were crushed with 5 mL of hot ethanol; the extract collected was used for the estimation of reducing sugars, total phenols, ortho dihydric (OD) phenol, amino nitrogen and protein percentages. Results and discussion. For all the morphogenetic characters studied, except the shoot number, there were significant interactions between the Citrus species and the different concentrations of BAP and kinetine. Increased concentration of cytokinins reduced the amount of total phenol, OD phenol and total protein. Calamondin recorded the lowest percent of reducing sugar and protein. The maximum amount of reducing sugars was recorded for C. volkameriana. Supplementation of BAP resulted in the highest amount of total and OD phenols, whereas kinetin improved the reducing sugar and amino nitrogen.