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 หัวเรื่อง:ไม่มีชื่อไทย (ชื่ออังกฤษ : Synergistic Effects of Sesame Oil with Cypermethrin on the Survival and Detoxification Enzyme Activity of Plutella xylostella L. Larvae) ผู้เขียน: ดร.สุรพล วิเศษสรรค์, รองศาสตราจารย์ ,  John Milne, มัณฑนา มิลน์, Pintip Kanasutar สื่อสิ่งพิมพ์:pdf AbstractTwo types of insect-toxicity tests, (1) contact and (2) no-choice leaf dipping test, were conducted using the insecticide cypermethrin without piperonyl butoxide (PB), cypermethrin with PB and cypermethrin with sesame oil against the 2nd –3rd instar larvae of Plutella xylostella L. Sesame oil showed good synergism with cypermethrin yielding synergistic ratios (SR) that ranged from 1.54 – 6.33 in the contact method and 2.04-5.88 in the no-choice leaf dipping method and were comparable to using PB, which showed SR’s of 6.33 and 6.71, respectively. Both PB and sesame oil mixed together with cypermethrin inhibited monooxygenase activity by approximately two-third but induced glutathione–S-transferase ca. 2-3 folds in both methods. The synergists had no effect on esterase activity (CF ca. 1.2). Residues of cypermethrin in the larvae increased by 1.29 – 2.57 folds in the treatments with added sesame oil compared to a 2.86 fold increase when PB was added, using the contact method. The no choice leaf dipping method revealed that cypermethrin residue levels increased by 2.82 – 6.91 fold with added sesame oil and 8.27 fold with added PB. This indicated that both PB and sesame oil played the same role in the inhibition of an enzyme, possibly monooxygenase. Field trials with Chinese kale showed the same trends that were evident in the laboratory work. The addition of sesame oil to the insecticide reduced the larval population by 70-80 percent while the addition of PB reduced the larval population by up to 88 percent in the kale crop. Monooxygenase activities of insect larvae collected in the field from kale sprayed with cypermethrin plus synergist (sesame oil or PB) were lower than those from kale treated with insecticide alone. The results in terms of synergism and changes in enzyme metabolism were discussed. |
หัวเรื่อง:ไม่มีชื่อไทย (ชื่ออังกฤษ : Toxicity of 4,11-Selinnadien-3-one from Nutsedge (Cyperus rotundus L.) Tuber Extracts to Diamondback Moth Larvae (Plutella xylostella L.), Detoxification Mechanisms and Toxi ผู้เขียน:ดร.สุรพล วิเศษสรรค์, รองศาสตราจารย์, Mantana Milne, John Milne สื่อสิ่งพิมพ์:pdf AbstractTubers of nutgrass (Cyperus rotundus L.) were collected from various locations of Thailand during the summer and rainy seasons. Toxicity against the diamondback moth (Plutella xylostella L.) was observed using different concentrations of the active compound, 4,11-selinnadien-3-one. The toxic effects were also determined on mice (Mus musculus), fish (Poecillia reticulata) and bee larvae (Apis florea). It was found that the active principle of nut grass was higher in summer than that in rainy season by ca. 2 folds. This active principle varied according to geographical vareas with Chanthaburi and Chaing Mai producing the highest amounts of 4,11-selinnadien-3-one (0.13-0.16% ai. yield) compared with the other. The LC50 against 2nd–3rd instar larvae of diamondback moth were 7-12 ppm. Detoxification enzyme activities as well as synergistic effects revealed that monooxygenase, esterases and some degrees of glutathione-S-transferase played a role in detoxification. Furthermore, synergists, PB and TPP, could raise the effectiveness of the active principle up to ca. 2-6 fold. At 2,000 ppm of 4,11-selinnadien-3-one, exposed mice showed no sign of acute dermal, acute oral or eye irritation effects. However, the active principle was toxic to other non target organisms with LC50 of 28.01 ppm and 10.8 ppm to 1-month old guppies and bee larvae, respectively. |
หัวเรื่อง:ไม่มีชื่อไทย (ชื่ออังกฤษ : Effects of Mangosteen’s Peels and Rambutan’s Seeds
on Toxicity, Esterase and Glutathione-S-transferase
in Rice Weevil (Sitophilus oryzae L.)) ผู้เขียน:ดร.วสกร บัลลังก์โพธิ์, ศาสตราจารย์ , ดร.สุรพล วิเศษสรรค์, รองศาสตราจารย์, John Milne, ดร.สมชัย พรบันลือลาภ, รองศาสตราจารย์ สื่อสิ่งพิมพ์:pdf AbstractPeel of Mangosteen (Garcina mangostana L.) and seed of rambutan (Nephilium lappaceum L.)
were attracted by Soxhlet’s extraction using ethanol as a solvent. Both extracts were trialed with adult rice
weevils (Sitophilus oryzae L.) by the impregnated filter paper method for the peel of mangosteen extracts,
weevils showed LC50 at 24 hours at 4.91 ? 1.19%w/v. Seed of rambutan extracts showed LC50 at 6.81
? 1.04%w/v.The addition of synergists, PB, TPP and DEM in the extracts reduced overall LC50 showing
SR of ca. 1.3-1.6 folds. The in vitro enzyme studies in lived rice weevil after be tested in both extract at
12 hours showed mangosteen’s peel extracts inhibited esterase and glutathione-S-transferase (GST)
activities ca. 1.6 time. Rambutan’s seed extracts reduced esterase and GST activities ca. 1.33- 1.63 fold.
The addition of synergists decreased activities of these enzymes more than 50% showing of CF ca. 1.19-
12.17. This result suggested that synergists in the extracts could increase efficiency for the control of rice
weevils. |
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