Aqueous extract of Moringa oleifera leafin the management of insect pest of cabbage plant both in the laboratory and field
Confidence U Ogbonna, Nnaemeka J Okonkwo, Edith N Nwankwo, Moses N Alo, Chuwkudi M Egbuche, Lilian C Ezemuoka, Kindness C Irikannu, Chikodili B Ukonze
Cabbage is an important vegetable, eaten and grown worldwide. It is a rich source of vitamin A, B and C, fiber and beta-carotene. However, a wide spectrum of insect pest affects the production of cabbage causing considerable damage to the plant. To manage these insect pests, farmers have resulted in the massive use of synthetic insecticides, leaving residues in cabbage heads, contamination of water bodies, hazardous effect on human and livestock. Especially since cabbage is eaten almost raw as salads, then the production process becomes a matter of importance. The diamondback moth Plutella xylostella L. (Lepidoptera: Plutellidae) and cabbage aphids Brevicoryne brassicae L. (Hemiptera: Aphididae) are the two most important insect pest of cabbage. Botanicals have shown to be effective against many insect pests and are cheap, always available, easily degradable and environmentally friendly. Therefore, the bio-insecticidal effect of aqueous extract of Moringa oleifera leave was assayed against insect pest complex of cabbage in the laboratory and field at various concentrations (90, 45, 22.5, 11.3, and 5.6 µL/mL). In the laboratory, P. xylostella larvae and apterous B. brassicae adult wereassayed by direct application and leaf dip assay respectively. At 90 µL/mL, Moringa oleifera leave, recorded 86.7% and 83.3% mortality after 6 days of exposure against P. xylostella larvae and B. brassicae respectively. Also 90% and 80% residual mortality were obtained against P. xylostella larvae and B. brassicae respectively after 10 days of exposure. At 90 µL/mL, repellency of 93.94% and 87.88% against P. xylostella and B. brassicae were recorded respectively. Larval damage on leaves treated with M. oleifera leave extract was as low as 3.33%. M. oleifera leave extract had the lowest LD50 of 21.71 and 29.10µL/mL for P. xylostella and B. brassicae respectively. In the field, botanical treated plots were observed to have reduced number of insect infestation and damage. Higher yield were recorded on botanical treated plots compared to the control while the yield recorded at 90 µL/mL were not significantly different from the standard check Lambda-cyhalothrin. This study have shown the potential of aqueous M. oleifera leave extract as a good alternative for the control of cabbage insect pests.
Confidence U Ogbonna, Nnaemeka J Okonkwo, Edith N Nwankwo, Moses N Alo, Chuwkudi M Egbuche, Lilian C Ezemuoka, Kindness C Irikannu, Chikodili B Ukonze. Aqueous extract of Moringa oleifera leaf in the management of insect pest of cabbage plant both in the laboratory and field. International Journal of Entomology Research, Volume 6, Issue 2, 2021, Pages 88-98