Synergistic effect of entomopathogenic fungusFusarium oxysporumextract in combination with temephos against three major mosquito vectors

Abstract

Mosquito control using chemical insecticides is facing a major challenge due to development of insecticide resistance. Improving the efficiency of existing insecticides using synergistic secondary metabolites of biological origin is increasingly being researched. Herein, we evaluated the toxicity of Fusarium oxysporum extract alone and in binary combinations with temephos, on larvae and pupae of Anopheles stephensi, Aedes aegypti and Culex quinquefaciatus. F. oxysporum extract was characterized using TLC, FT-IR and GC-MS. After 24 h of exposure, the binary combination of temephos + F. oxysporum extract (1:1 ratio) was highly toxic to larvae of An. stephensi (LC: 35.927 μg/ml), Ae. aegypti (LC: 20.763 μg/ml) and Cx. quinquefasciatus, (LC: 51.199 μg/ml). For pupae LC values were 38.668, 26.394, and 72.086 μg/ml, respectively. Histology studies of mosquitoes exposed to F. oxysporum extract showed vacuolation in epithelium, as well as in adipose, and muscle tissues of larval midgut. Overall, our results show that the synergistic combination of temephos and F. oxysporum extract is highly effective to control mosquito young instars.

Identification and characterization of immature Anopheles and culicines (Diptera: Culicidae) at three sites of varying malaria transmission intensities in Uganda

“…Aquatic habitats were defined using a method that was described previously in the Gambia [25]: (1) freshwater marsh (swamp), was a large water body containing vegetation and tall papyrus, (2) river fringe, was the shallow edge of a permanent stream, associated with grass and tall reeds in deeper parts, (3) puddle was a small natural water-filled depression, (4) pool was a large manmade depression holding water, (5) water channel was an open flowing water used for irrigation, (6) foot print was a depression made by the foot of a person, cow or other animal where water collects, often associated with edges of large water bodies, (7) tire track was a waterfilled depression made by a vehicle, (8) artificial pond was a large human-made permanent water body, (9) sand pit was a depression made after extraction of sand or bricklaying, (10) container was a discarded plastic or metal waste, (11) pit latrine was any hole used as a toilet containing water, (12) rice field was a flooded area used to grow rice, and (13) open drain was man-made and constructed for the purpose of getting rid of water (14) Lake fringe was the shallow edge of a lake, (15) flood water was a large natural water-filled depression a rising especially after heavy rains.…”

“…LSM targets immature mosquito populations by removing standing water, flushing aquatic habitats, or adding insecticides, microbial larvicides or natural predators to standing water to kill larvae [11][12][13]. Adult Anopheles control, complemented by larval control can significantly reduce malaria transmission in sub-Saharan Africa [13][14][15][16] and has been recommended to reduce outdoor transmission [17]. LSM has been incorporated in Integrated Vector Management (IVM) as a malaria control policy in Uganda [18] and scaling LSM in Uganda is highly recommended [19].…”

Identification and characterization of immature Anopheles and culicines (Diptera: Culicidae) at three sites of varying malaria transmission intensities in Uganda.

“…Aquatic habitats were de ned using a method that was described previously in The Gambia [25]: (1) freshwater marsh (swamp), was a large water body containing vegetation and tall papyrus, (2) river fringe, was the shallow edge of a permanent stream, associated with grass and tall reeds in deeper parts, (3) puddle was a small natural water-lled depression, (4) pool was a large man-made depression holding water, (5) water channel was an open owing water used for irrigation, (6) foot print was a depression made by the foot of a person, cow or other animal where water collects, often associated with edges of large water bodies, (7) tire track was a water-lled depression made by a vehicle, (8) arti cial pond was a large human-made permanent water body, (9) sand pit was a depression made after extraction of sand or bricklaying, (10) Container was a discarded plastic or metal waste , (11) pit latrine was any hole used as a toilet containing water, (12) rice eld was a ooded area used to grow rice, and (13) open drain was manmade and constructed for the purpose of getting rid of water (14) Lake fringe was the shallow edge of a lake s, (15) Flood water was a large natural water-lled depression a rising especially after heavy rains.…”

“…LSM targets immature mosquito populations by removing standing water, ushing aquatic habitats, or adding insecticides, microbial larvicides or natural predators to standing water to kill larvae [11][12][13]. Adult Anopheles vector control, complemented by larval control can signi cantly reduce malaria transmission in sub-Saharan Africa [13][14][15][16] and has been recommended to reduce outdoor transmission [17]. LSM has been incorporated in Integrated Vector Management (IVM) as a malaria control policy in Uganda [18] and scaling LSM in Uganda is highly recommended [19].…”

Peer Review #3 of "Combined effect of the entomopathogenic fungus Metarhizium robertsii and avermectins on the survival and immune response of Aedes aegypti larvae (v0.1)"

“…However, few studies have been carried out to determine the effect of combined treatment with entomopathogenic fungi and other insecticides or plant or microbial metabolites as a potential tool for improving mosquito larvae control. Synergistic effects between entomopathogenic fungi and some chemical insecticides (temephos, spinosad) (Shoukat et al, 2018;Vivekanandhan et al, 2018) or biological agents (Azadirachta indica) (Badiane et al, 2017) on the mortality of mosquito larvae have been found. However, the physiological and biochemical aspects of this synergism were not considered.…”