Field experiments were conducted at the Agricultural Research Station, Bhavanisagar, Tamil Nadu, India during 1999 to 2000 in Inceptisols to evaluate boron fertilizers (borax, boric acid, Agribor) and to assess the effect of the mode and level of B application on the total B uptake and yield of sunflower and green gram. The experimental field was found to be deficient in available B (0.35 mg kg-1). Sunflower was raised as the main crop. Different B levels (0.5, 1.0, 1.5and 2.0 kg B ha-1)as soil application and two levels of foliar spray (0.2% and 0.3%) were compared with the control. The treatments were superimposed on the recommended dose of NPK. After harvestingthe main crop of sunflower, the residual effect of B was studied by raising green gram on the same field. The results revealed that the application of all the levels of B resulted in a significant increase in the B uptake and yield of sunflower as compared to the control. The highest yield was recorded for the soil application of B at a rate of 2.0 kg ha-1. The yield increase of sunflower was 3.6 to 15.8% and 7.2 to 18.9% over the control for seed and stalk, respectively. The green gram grain yield increased by 4.2 to 13.5% after the application of 1.0 and 2.0 kg B ha-1 to the main crop. No residual effect was observed for the lowest level of B application (0.5 kg ha-1). Agribor is equally as effective as borax in influencing the B nutrition of both the crops.
Authors:C. Bharathimatha, Sabitha Doraiswamy, R. Rabindran, P. Renukadevi and R. Velazhahan
Seed extract of Harpullia cupanioides was tested against infection by Tomato spotted wilt virus (TSWV), Rice tungro virus (RTV) and Cowpea aphid borne mosaic virus (CABMV). Seed extract of H. cupanioides (10%) when sprayed on test plants 24 h before virus inoculation significantly inhibited virus infections. Percentage inhibition of TSWV in local lesion host by 10% seed extract of H. cupanioides was found to be 90.9. Pre-inoculation application of 10% seed extract of H. cupanioides provided 87.5% inhibition of CABMV infection. The seed extract (10%) sprayed rice plants recorded RTV infection of 48% as against 100% in control.
Authors:N. Lavanya, R. M. Ramiah, A. Sankaralingam, P. Renukadevi and R. Velazhahan
Sunflower necrosis virus (SFNV) has a wide host range, which includes many cultivated crops and weed hosts. Fifteen plant species belonging to Fabaceae, 3 plant species belonging to Malvaceae, 6 plant species belonging to Cucurbitaceae, 3 plant species belonging to Solanaceae and one plant species each belonging to Caricaceae and Moringaceae were found to be additional hosts for SFNV. Besides, weeds such as Trianthema portulacastrum, Priva leptostachya, Digeria arvensis, Clitoria ternatea, Solanum nigrum, Vernonia cineraria, Trichodesma indicum and many other species were found to act as hosts for SFNV.