Brown Stink Bug Mortality by Seed Extracts of Tephrosia Vogelii Containing Deguelin and Tephrosin

Abstract

Extracts of the seeds of Tephrosia vogelii Hook. f. were studied in relation to its chemical composition and toxicity to the brown stink bug Euschistus heros (F.). The extracts were obtained in ethyl acetate and ethanol in the sequence according to the polar nature of the solvents. Extracts were sprayed in concentration of 1.0, 2.5, 5.0, 7.5 and 10% on third-instars nymphs and adults, and mortality was recorded. Presence two rotenoids in ethyl acetate was detected, with analyzed with gas chromatography-mass spectrometry (GC-MS). Crude fraction analyses confirmed the presence of these rotenoids (tephrosin-2.71% in ethyl acetate and 3.66% in methanol; and deguelin-10.46% in ethyl acetate and 1.22% in methanol) and three other rotenoids in small amounts. Eight days after applications, ethyl acetate caused more stink bugs mortality and on less time than ethanol extract, because great quantity of rotenoids, as polarity. Concentrations above to 1 and 2.5% of the ethyl acetate extracts caused mortality above 80% of the nymphs and adults of E. heros, respectively. Concentration were considered high, thus chemist analyzes demonstrated high rotenoids presence. In conclusion, seed T. vogelli extracts, rich in deguelin and tephrosin (3:1), cause mortality of E. heros, however, high concentration are necessary.

Variation in Rotenone and Deguelin Contents among Strains across Four Tephrosia Species and Their Activities against Aphids and Whiteflies

“…Sixteen species were evaluated by Irvine and Freyre [ 8 ], and 14 were found to biosynthesize some rotenoids. The highest amount of rotenoids was produced by Tephrosia vogelii Hook f., including rotenone, deguelin, rotenolone, and tephrosin in the leaves, petal, stems, and roots [ 1 , 9 , 10 , 11 , 12 ]. Leaves, however, accounted for 80–90% of the biosynthesized rotenoids [ 13 ].…”

“…Deguelin is a derivative of rotenone with a formula of C 23 H 22 O 6 and molecular weight of 394.42 [ 15 ]. Deguelin has been found to have strong anticancer properties [ 10 , 16 ], but there is limited information about deguelin as a botanical pesticide [ 11 , 17 ], and no report is available about its mode of action as a botanical insecticide.…”

Activity of extracts from selected Tanzanian spices on major fungal pathogens and blight diseases of Tomato

“…Garlic and ginger are utilised for their essential oils against a range of pests and pathogens (Koundal et al, 2018). Neem (Azadirachta indica), moringa (Moringa oleifera) and tephrosia (Tephrosia vogelii) have been reported to have insecticidal properties and used to manage a number of insects attacking different crops with notable success (Alao et al, 2018;Mikami et al, 2018;Seifi et al, 2018). The bioactive compounds in some plants may also have repellence effects without necessarily killing the insects (Babu et al, 2018).…”

“…A section of farmers in Same District were aware of botanical pesticides and had used farm preparations from Azadirachta indica, Tithonia diversifolia, Tephrosia vogelii and Moringa oleifera to manage pests on vegetables and maize. The pesticidal properties and the availability of commercial formulations of these plants has been documented (Alao et al, 2018;Dimetry & El-Behery, 2018;Mikami et al, 2018;Seifi et al, 2018;Ngom et al, 2018).…”