Evaluation of the insecticidal activities of some medicinal plant  tinctures against maize weevils (Sitophilus zeamais)

Melkie, Tigabu

dc.contributor.author	Melkie, Tigabu
dc.date.accessioned	2018-10-25T08:47:55Z
dc.date.available	2018-10-25T08:47:55Z
dc.date.issued	2018-10-25
dc.identifier.uri	http://hdl.handle.net/123456789/9046
dc.description.abstract	The maize weevil is a serious pest of stored products in tropical and subtropical countries. Botanical pesticides have become viable alternatives of synthetic insecticides in weevil control. This study was conducted to determine the efficacy of ethanol tinctures of some botanicals on the mortality of maize weevils (Sitophilus zeamais). The test plants were collected from different areas of the Amhara Region. The collected plants were dried under shade, powdered and tinctures were made by immersing plant powders in to 70% ethanol (1:5 w/v) for 21 days. The study was conducted in Bahir Dar University, Biomedical Research Laboratory. Two types of experiment; toxicity test and grain damage test were conducted using plant tinctures. In toxicity test, 1 ml, 1.5 ml and 2 ml of each tincture was added to 20 gram of maize grains, put in a beakers, mixed well,10 adult weevils added to each beaker, covered with muslin cloths and weevils mortality observed at the 6 th , 12 th , 24 th , 48 th , 72 th hours and weekly. In the grain damage test, tinctures of each plant materials (10 ml, 15 ml and 20 ml) were mixed thoroughly with 200 gram maize grains in the beaker, 20 adult weevils were added, covered with muslin cloths and tightened with rubber band and placed at room temperature for three months. The experiment was conducted in a completely randomized design (CRD), with three replications. The data were analyzed using ANOVA procedure using SAS (2003). Tukey test was used for mean comparison between treatments. After three months, grain weight loss, number of holes, weevils‟ mortality and seed germination was determined. In toxicity test, the result showed that the plant tinctures were toxic to maize weevils in dose and exposure time dependent manner. Damage was expressed by weight loss and number of holes. The weight loss in all plant tinctures and doses 2%, number of holes 1% and control had 9%. Percent weevil mortality B. anti dysentrica 100%, N. exaltata gametophyte 99.44%, L. camara 99.88%, C. macrostachyus 98.33% and the control had 45%. The number of weevil mortality also increased with increase in plant tincture doses. All plant tinctures killed the weevils effectively but the plant tinctures affect seed germination (F=7.14, P<0.0001) and their dose (F=9.83, P<0.0001), so; these plant tinctures were effective in protecting storage grains but not suitable for seed germination. Key words: Maize, weevils, Sitophilus zeamais, Brucea antidysenterica, Croton macrostachyus, Lantana camara and Nephrolepis exaltata.	en_US
dc.language.iso	en	en_US
dc.subject	Biology	en_US
dc.title	Evaluation of the insecticidal activities of some medicinal plant tinctures against maize weevils (Sitophilus zeamais)	en_US
dc.type	Thesis	en_US