| dc.description.abstract | Sitophilus zeamais Motschulsky, 1885 (Coleoptera: Curculionidae) is one of the main insects of stored grains, causing considerable damages and compromising the final quality of the product, it makes it impossible to use and commercialize. Chemical control (insecticides) is the most used to minimize the effects of this insect. However, due to the indiscriminate use, the insecticides have been causing undesirable effects such as selection of resistant insect populations, residues in food and environmental contamination. Thus, alternative methods such as the use of essential oils have been presented as an effective and promising way to control S. zeamais. In this context, the objective of this work was to evaluate, under laboratory conditions, the insecticidal effect of Cymbopogon nardus (Citronella), Pogostemon cablin (Patchouli) and Lavandula dentada (Lavender) on S. zeamais. For this, they were tested in the methodologies of volatilization, immersion and application in rice grains. For the bioassays the essential oils were used in the 5% concentration, diluted in sterile distilled water containing Tween 80® (0,01%). The experimental design was completely randomized in six replicates with 15 insects adults not sexed. Every 24 hours, for a period of 10 days, the number of insects dead was evaluated. For the volatilization method, the essential oil of P. cablin and L. dentada caused mortality to S. zeamais in 63,33% and 55,55%, respectively, after 240 h of evaluation. The C. Nardus essential oil(15,55%) did not differ from the control (5,55%) for this technique. For the method of application in the food, the oils of C. Nardus (75,55%), P. cablin (68,88%) e L. dentada (66,66%) presented an insecticidal effect causing significant mortality on S. zeamais, after 10 days of evaluation. In the immersion technique the oils P. cablin, C. Nardus and L. dentada resulted in significant mortality on S. zeamais with values of 98,88%, 93,33% and 75,55%, respectively, after 10 days of evaluation. The essential oils tested in this study show insecticidal contact, fumigation and inhalation activity, highlighting the oils of P. cablin e L. dentada. | |
