Evaluation of Botanical Insecticides for the Management of Potato Tuber Moth, Phthorimaea operculella (Zeller) (Lepidoptera: Gelechiidae) Under Laboratory Condition
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Date
2015-11
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Addis Ababa University
Abstract
Potato has high yield potential, nutritional quality and a short growing period but, it has major constraints in Ethiopia that include diseases, insect pest such as Phthorimea operculella. The objective of this study was to evaluate Chrysanthemum cinerariafolium (Anonymous), Millettia ferruginea (Hochst) and Azadirachta indica (A. Juss) against P. operculella. Three sets of experiments were conducted at Holetta Agricultural Research Center under laboratory condition. Five treatments with three replications in completely randomized design were used. In experiment1: the treatments were 0.33mg/ml of birbera seed powder extracted using ethanol, 0.33mg/ml pyrethrum flower powder, 0.33mg/ml combination of birbera seed powder extracted using ethanol and pyrethrum, 0.01ml/ml of ethanol extracted neem oil and water. Then 25 ml of solution were sprayed on potato seedling per pot through dispenser sprayer. After one hour and fifty minutes of treatment application, ten larvae per pot were released. As a result there was no significant difference between botanicals larval mortality, leaf and petiole percent damage. Pyrethrum was a good killer of larva (86.66%) next to the combination (83.33%). There was significant difference in larval mortality between botanicals and water (F4,10 at 0.05= 41. 68, p < 0.0001). In experiment 2 and 3: similar rates of treatments and procedure were used. 0.33 mg/ml of birbera seed powder extracted using ethanol, 0.33 pyrethrum flower powder, 0.001ml/ml of neem oil extracted using ethanol and 0.33mg/ml combination of birbera seed powder extracted using ethanol with pyrethrum. After preparation of botanicals in solution form five tubers were dipped for one hour and fifty minutes, taken out and air dried for one hour. Tubers received the same treatment were put with enough space between tubers into a transparent plastic cage and 25 larvae were released per cage. There was significance difference between birbera and the remaining treatments. All birbera treated tubers had the least recorded of fecal materials (F4, 10 at 0.05= 12.73, P <0.0006), active galleries (F4, 10 at 0.05= 11.07, P< 0.0011) and larval mortality per cage (F4, 10 at 0.05=18.47, P <0.0001). In experiment three; two pairs of adults were released on treated tubers to see the ovipostion response. There was significance difference between botanicals in number of eggs laid (F, 10 at 0.05=4.5, p<0.024) and hatched eggs/ cage (F4, 10 at 0.05 =3.44, p<0.051). In terms of all parameters measured birbera either single or mixed with pyrethrum gave the best control of P. operculella under storage and can be recommended against the pest. Key words: Potato, Birbera, Pyrethrum, Neem, Ethanol, P. operculella.
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Keywords
Potato, Birbera, Pyrethrum, Neem, Ethanol, P. Operculella