Phytochemical Screening of Selected Botanicals and their Effectiveness Against Maize Weevil (Sitophilus Zeamais Motsch.) at Paklihawa, Rupandehi, Nepal

Laboratory experiment was done to perform the phytochemical screening of six locally available botanicals (Azadirachta indica Juss, Artemisia dubia Wall, Lantana camara L, Parthenium hysterophorus L, Justicia adhatoda Linn. and Moringa oleifera L.) and their effectiveness to control the maize weevil (Sitophilus zeamais Motsch.) at Agriecology lab of Institute of Agriculture and Animal Science, Paklihawa Campus, Rupandehi, Nepal. Seven treatments (leaf extract of A. indica, A. dubia, L. camara, P. hysterophorus. J. adhatoda and M. oleifera and distilled water as control) applied at 3 different doses (0.5, 1 & 2g/50g seeds) were arranged in CRD design with 3 replications. Result of mortality test of maize weevil revealed that, at highest concentration of L. camara powder (T17- 2g/50 gm seeds) mortality of maize weevil was observed up to 85% at 45 DAT. Whereas number of damaged grain was lowest in T17 (L. camara powder- 2g/50 gm seeds). The effectiveness of botanicals was found to increase with increasing the concentration. Besides that, Justicia adhatoda (2g/50g seeds) and Artemisia dubia (1g/50g seeds) were also found as good candidates to use for the control of Sitophilus zeamais. Qualitative tests done for the presence of various phytochemicals showed that Azadirachta indica Juss and Artemisia dubia Wall. were found to contain most of the tested metabolites among all botanicals. Most of those phytochemicals were extracted by the aqueous solution rather than other 3 menstrums used (acetone, methanol and petroleum ether). Similarly, quantitative test revealed that percentage of alkaloid was found 18.01%, 17.78%, 17.75%, 11.58%, 8.20%, 6.78% and flavonoid15.32%, 13.63%, 12.86%, 11.36%, 7. 51% 2.85% respectively in L. camara L. P. hysterophorus L., J. adhatoda Linn., M. oleifera L., A. indica Juss. and A. dubia Wall. Leaf extract of L. camera found to contain highest botanicals extract reach in alkaloid and flavonoid mayhave insecticidal property and could be use as grain protectant percentage of alkaloid (18.01%) as well as flavonoid (15.32%) So, it was concluded that the locally available against the maize weevil at storage condition in cost effective and eco-friendly manner; however, application at proper dose is necessary to maintain the efficacy at higher level.

Insecticidal potency of mixtures of plant powders and Actellic SuperTM (Pirimiphos-methyl + Permethrin) on Callosobruchus chinensis F. and Sitophilus zeamais Motch

Insect pests still cause substantial quantitative and qualitative grain loss ranging from 20 to 100% in small holder farming systems in tropical countries. Synthetic pesticides are recommended as stop gap measures for the management of stored product insect pests. However, their application has not been fully exploited in small scale farming due to environmental, health, and economic concerns. As a result, new researches have shifted focus to exploiting pesticidal plants as alternatives to synthetic pesticides. Therefore, the current study evaluated mixtures of plant powders and reduced amount of Actellic superTM (pirimiphos-methyl + permethrin) as alternative insecticide formulation against Callosobruchus chinensis and Sitophilus zeamais. Green grams and wheat grains were mixed with a mixture of plant powders in the ratios of 1:1, 1:3 and 1:9 to obtain four rates (0.0, 2.0, 6.0 and 10%w/w). Grains and plant powders were also mixed with reduced amount (10, 25, and 50 %) of recommended rate of Actellic SuperTM to obtain dosages as above. Twenty unsexed adults, 1-5 day old S. zeamais and C. chinensis were introduced into treated grains. The mixture of C. lusitanica: T. vogelii powders in the ratios of 1:1, 1:3 and 1:9 caused mortality in C. chinensis of 55, 95 and 85%, respectively. At the same ratio, E. saligna: L. camara mixture produced mortality in S. zeamais of 77, 82, and 85% respectively. In mixture of C. lusitanica and T. vogelii and reduced amount of Actellic SuperTM by 50% the mortality of C. chinensis was 85 and 80 % respectively. Similarly, E. saligna and L. camara and reduced amount of Actellic SuperTM by 50% caused a mortality of S. zeamais of 48 and 97% respectively. The application of plant powders and reduced amounts of synthetic insecticide has the potential to be applied in stored product pest control