Insecticidal Activity of the Soil in the Rhizosphere of Viburnum odoratissimum against Solenopsis invicta (Hymenoptera: Formicidae)

Methyl salicylate produced by Viburnum odoratissimum is known to exert lethal or sublethal effects on insects. Replacing conventional pesticides with insecticidal plants is necessary for environmental protection. We evaluated the behavioral and toxicological responses of the red imported fire ant (RIFA Solenopsis invicta)( Hymenopter: Buren Formicidae) at different soil depths in the rhizosphere of V. odoratissimum. Results of insecticidal activity bioassays indicated that the mortality for minor and major ants in soil at depths of 0-10 cm at days 11 and 12 both ranged from 68.75% to 100.00%, with repellent rates of 83.54%–100.00% and 85.31%–100.00%, respectively. In behavioral ability tests, 85.45%–100.00% of minor ants and 86.74%–94.85% of major ants lost their ability to grasp after nine days, with crawl rates at only 0.00%–29.25% and 0.00%–55.77%, respectively. Therefore, we conclude from the result that the soil under V. odoratissimum at depths of 0-10 cm exhibited excellent insecticidal effect in controlling RIFA.Methyl salicylate produced by Viburnum odoratissimum is known to exert lethal or sublethal effects on insects. Replacing conventional pesticides with insecticidal plants is necessary for environmental protection. We evaluated the behavioral and toxicological responses of the red imported fire ant (RIFA Solenopsis invicta, Buren) (Hymenoptera: Formicidae) at different soil depths in the rhizosphere of V. odoratissimum. Results of insecticidal activity bioassays indicated that the mortality for minor and major ants in soil at depths of 0-10 cm at days 11 and 12 both ranged from 68.75% to 100.00%, with repellency rates of 83.54%-100.00% and 85.31%-100.00%, respectively. In behavioral ability tests, 85.45%-100.00% of minor ants and 86.74%-94.85% of major ants lost their ability to grasp after nine days, with crawling rates at only 0.00%-29.25% and 0.00%-55.77%, respectively. Therefore, we conclude from the result that the soil under V. odoratissimum at depths of 0-10 cm exhibited excellent insecticidal effect in controlling RIFA.

Performance of various admixtures for controlling ground nutseed beetle in storage condition

Groundnut is the largest oilseed in India in terms of production. Caryedon serratus (Olivier) (Bruchidae: Coleoptera) is one of the major pests of groundnut. It infests groundnut by making characteristic round holes on them which causes qualitative and quantitative losses. Considering limitations of chemical use, there is a need for alternate methods. A laboratory experiment was conducted to determine the efficacy of insecticidal plants: neem (Azadirachta indica), begunia (Vitex negundo), naguaeri (Lantana camera), custard apple (Annona reticulatnm) and powder of turmeric rhizome and red chili against the groundnut bruchid (Caryedon serratus). The experiment was laid out in a completely randomized design (CRD) with four replications. Parameters assessed included number of number of adults that emerged from each treatment,percentage of loss of the pod in 1st,2nd and 3rd month. The relative efficacy of plant product admixtures @2.0%(w/w) showed that, best protection was offered by neem leaf powder followed by turmeric rhizome powder. Weight loss of pods in neem leaf powder was 1.1%,4.0% and 10.13% on comparision to 14.2%, 17.63 and 29.23% in control after first, second and third month respectively.

Comparative Efficacy of Insecticidal Plants on the Management of Groundnut Bruchid (Caryedon Serratus)

Laboratory study was conducted to determine the efficacy of insecticidal plant extracts Azadirachta indica A. (Juss), Lantana camara L. (Verbenaceae), Eupatorium odoratum L. (Asteraceae), Tephrosia vogelii Hook, Afromomum melegueta K.M. (Schumann) and Ocimum gratissimum (L) leaves against groundnut bruchid beetle (Caryedon serratus), and a synthetic insecticide (Cypermethrin) (10EC)) under ambient condition of temperature and relative humidity (30°C and 72%). One hundred grams of shelled groundnut was weighed into jute bags and treated with powders of the insecticidal plants. Both treated and untreated bags of groundnut were then infested with newly emerged adult of C. serratus (20 per bag) and covered. The experiment was laid out in Completely Randomized Design (CRD) and replicated four times. Parameters assessed included number of egg oviposited, number of eggs hatched (eclosion) and number of adults that emerged from each treatment, total developmental period (egg – adult), sex ratio of the emerged adults and finally percentage germination of the treated seeds. Data collected were analyzed using analysis of variance and treatment means were separated using Duncan multiple range tests at P ≤ 0.05 level of significance. Results showed that A. indica, L. camara, T. vogelli, A. melegueta and O. gratissimum treated seeds significantly recorded lowest mean number of eggs, reduced damage by C. serratus and increased germination percentage compared with E. odoratum and control. In conclusion, A. indica, L. camara, T. vogelli, A. melegueta and O. gratissimum have the potentials as alternatives to synthetic insecticides in the management of C. serratus by resource poor farmers.

Effectiveness of crushed fresh leaves of Boscia senegalensis Lam Ex. Poir. harvested in Dakar and Richard Toll on Sitophilus zeamais (Motschulsky)

The maize is one of the most produced worldwide cereals. Its conservation in stock is attacked by many pests that cause huge loss to the qualitative and quantitative level. Several alternative methods of control resulting in the insecticidal plants replace chemical pesticides. Among these methods, fumi-gation has proved very effective on insects’ food stored. In the present work, fumigating insects of Sitophilus zeamais to different doses of fresh crushed leaves of Boscia senegalensis showed strong insecticidal activity of this plant depending on the locality. Leaves of two localities, Dakar and Richard Toll have been tested. Statistical analysis of the mortality rate expressed in cu-mulative frequencies showed a significant difference (p<0.0001) between the groups tested and control groups. Leaves from Richard Toll gave 100% mortality within 24 h to 1 g / l while those collected in Dakar gave 100% in 24 h to a maximum dose of 9 g / l. We can explain this by significant differences in the rate of glucocapparin content in the leaves of this plant according to the locality and period of harvest. It should be noted that crops leaves were not done during the same periods. In this work, the best season to obtain a high efficiency is during dry season.