Preliminary study of wild spikenard leaf oil (Hyptis suaveolens (L.) Poit) sustained to neem extracted for control Aphis craccivoral Koch and Aphis gossypii Glov.

Investigation of Hyptis suaveolens (L.) wild spikenard leaf oil (H.S.) sustained to neem seed (Azadirachta indiaca var. siamensis (L.) (A.I.S.) extract for control Aphis craccivora Koch in yard long bean pod and Aphis gossypii in chilli pod were studied on July to September 1994 at Sakonakhon Agricultural. Research and Training Center (SARTC). The extraction of H.S. and A.I.S. were done by using steam distillation extraction. There were 4 treatments of which were practiced by sprayed solution of H.S., A.I.S. and mixture of H.S. plus A.I.S. extracted at ratio 1 : 1 (v/v) compared to sprayed distilled water as check treatment. The experiment was divided into two items, one was studied in chilli pod and the other was trial in SARTC's laboratory. At laboratory condition, the A. craccivora Koch was killed 51.4 percent of the total aphids in 24 hr 100 percent concentration of H.S. extractant. When determined on the effectiveness of A.I.S. performed on A. craccivora Koch at 50 and 100 percent concentration in 24 and 12 hrs were found that the aphids were killed 51.2 and 55.8 percent of the aphids, respectively. When inspected on mixture of H.S. plus A.I.S. treated on yard long bean aphids, at 25 50 and 100 percent concentration 12 and 6 hrs of the trial could kill the aphids 57.3, 60 and 76.8 percent of all aphids, respectively. When investigated H.S. treated on A. gossypii Glov. at 6.25 12.5 25 50 and 100 percent concentration and 1 3 6 12 24 hrs, respectively. The result was that all the concentration and period of mortality checked could kill the aphids less than 50 percent of tested aphids. When investigated A.I.S. tested on chilli aphids A. gossypii Glov. at 50 and 100 percent concentration, 12 and 6 hrs, the aphids were killed 58.2 and 51.5 percent of all aphids, respectively. When investigated on mixture of extractants performed on chilli aphid A. gossypii Glov. at 25 50 and 100 percent concentration 24, 12 and 6 hrs of inspection. The aphids were killed 52.1, 60.5 and 58.4 percent of all aphids, respectively. Chilli pod fresh weight was maximized when applied 50 percent concentration of H.S., 100 percent conc. of A.I.S and 100 percent concentration of the mixture were the best result, could harvest 57.1, 69.1 and 92 grams per plant, respectively and could harvest only 32.2 grams per plant from the check. Fresh weight of chilli stem, branches and rootparts were maximized when applied 50 percent concentration of H.S., 100 percent concentration of A.I.S., 100 percent concentration of mixture could get 30.1, 49.7 and 42.7 grams, respectively and for the check could get only 11.7 grams.