 หัวเรื่อง:ไม่มีชื่อไทย (ชื่ออังกฤษ : Monitoring Insecticide Resistance Development in Beet Armyworm, Spodoptera exigua (H?bner) (Lepidoptera: Noctuidae)) ผู้เขียน: Md. Abdullah, Ouab Sarnthoy,  ดร.ศิริพรรณ ตันตาคม, รองศาสตราจารย์ , Somchai Isichaikul, ดร.สุดาวรรณ เชยชมศรี สื่อสิ่งพิมพ์:pdf AbstractField collected larvae of beet armyworm, Spodoptera exigua (H?bner) were reared and evaluated for resistance against cypermethrin 10 EC, neem extract (Azadirachtin 0.1%) and Bacillus thuringiensis Berliner var. kurstaki (53,000 SU per mg) for 12 generations under laboratory condition by using leaf dip bioassay. Cypermethrin showed LC50 value of 251 ppm at F1 generation and decreased gradually to onward generations resulting LC50 value of 90 ppm at F12 generation for non-selection, whereas LC50 increased rapidly with a value of 8625 ppm at F12 generation under selection pressure. Neem extract exhibited LC50 value ranging from 3.98 ppm to 9.99 ppm for non-selection, whereas under selection pressure LC50 ranged from 4.38 ppm to 13.04 ppm throughout the generations. Bacillus thuringiensis var. kurstaki showed LC50 value which ranged from 7.3 ? 106 SU/L to 15.9 ? 106 SU/L for non-selection, and selection for resistance monitoring gave LC50 value ranged from 7.6 ? 106 SU/L to 73.9 ? 106 SU/L . Compared with non-selection strain, selection strain exhibited 95.83-fold, 1.44-fold and 5.6-fold increase in the LC50 for 12 generations against cypermethrin, neem extract and Bacillus thuringiensis var. kurstaki, respectively. |
หัวเรื่อง:ไม่มีชื่อไทย (ชื่ออังกฤษ : Efficacy of Cypermethrin, Neem Extract and Bacillus thuringiensis for Controlling Insect Pests of Vegetable Soybean) ผู้เขียน:Md. Abdullah, Ouab Sarnthoy, Somchai Isichaikul, ดร.ศิริพรรณ ตันตาคม, รองศาสตราจารย์ สื่อสิ่งพิมพ์:pdf AbstractField experiments were conducted during dry and wet seasons (1999-2000) at Kamphaeng Saen Campus of Kasetsart University, Nakhon Pathom, Thailand to evaluate the efficacy of cypermethrin 10 EC, neem extract (Azadirachtin 0.1%) and Bacillus thuringiensis var. kurstaki (53,000 SU/mg) in controlling the major insect pests of vegetable soybean. Melanagromyza sojae, Spodoptera litura, Spodoptera exigua, Helicoverpa armigera, Lamprosema indicata, Etiella zinckenella and Bemisia tabaci were the most abundant species in both seasons. Insecticides were sprayed at 10 days interval until harvest. Cypermethrin showed significantly better control among the treatments. Neem extract moderately suppressed the insect pests with statistically significant efficacy over the control. B. thuringiensis var. kurstaki showed less efficacy than neem extract but exhibited statistically significant efficacy over the control in most cases. Highest yield was recorded in cypermethrin treated plot (9.83 t/ha) followed by neem extract (8.39 t/h), B. thuringiensis var. kurstaki (7.98 t/ha) and control (6.22 t/ha) in dry season whereas yields were 5.83, 4.83, 4.0 and 2.83 t/ha for cypermethrin, neem extract, B. thuringiensis var. kurstaki and control in wet season, respectively. Additionally, Menochilus sexmaculatus and spider were found less in cypermethrin treated plots whereas in other treatments they were significantly higher in number. |