Impact of a Local Nigerian Rice Variety and Wheat on the Tolerance of Geographical Strains of Sitophilus oryzae to Dichlorvos
Olajire Ayodele Gbaye,
Emmanuel Ayobami Oyeniyi,
Muyideen Folorunsho,
Graham Holloway
Issue:
Volume 3, Issue 2, June 2019
Pages:
30-35
Received:
30 March 2019
Accepted:
5 May 2019
Published:
10 June 2019
Abstract: Rice weevil, Sitophilus oryzae, a cosmopolitan pest of stored cereals (including wheat and rice) is moved around inadvertently through global cereal trade. In this study, we consider the effect of strain origin and host food on the tolerance of S. oryzae to dichlorvos, a common insecticide used to protect stored grains in Nigeria. Three geographical strains of S. oryzae (Nigeria, Trinidad and Morocco) were bred separately on Ofada rice (a Nigerian local rice variety) and wheat and then exposed to dichlorvos. The data were analyzed using analysis of variance and General Linear Model, probit analysis was used to estimate LC50 and LC95 values. The strain by food combinations varied significantly in their tolerance to dichlorvos. Overall, the Nigerian strain was the least tolerant. Nonetheless, for all strains novel host food influenced their tolerance positively; wheat in the case of the Nigerian strain and Ofada rice for the exotic strains. The results were discussed in terms of varying body size among the strains and physiological effect when insects find themselves in novel environments. The risk posed to local Nigerian rice varieties is considered through the import of exotic strains of S. oryzae, especially when entering the country on wheat.
Abstract: Rice weevil, Sitophilus oryzae, a cosmopolitan pest of stored cereals (including wheat and rice) is moved around inadvertently through global cereal trade. In this study, we consider the effect of strain origin and host food on the tolerance of S. oryzae to dichlorvos, a common insecticide used to protect stored grains in Nigeria. Three geographica...
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Spatio-Temporal Dynamics of Glossinidae, Tabanidae and Stomoxyidae Around the Douala-Edea Wildlife Reserve in Cameroon
Hiol Victor,
Sieumeni Andre Djonguep,
Mamoudou Abdoulmoumini,
Sevidzem Silas Lendzele,
Njan-Nloga Alexandre Michel,
Nukenine Elias Nchiwan
Issue:
Volume 3, Issue 2, June 2019
Pages:
36-42
Received:
12 March 2018
Accepted:
27 March 2018
Published:
13 June 2019
Abstract: The objective of this work was to evaluate the diversity and composition of glossines, tabanids and stomoxes in the dry and rainy seasons at the Douala-Edéa Game Reserve (DEGR) using Biconical, Vavoua and Nzi traps. Three traps i.e. one of each type was pitched in the sampled sites with collection carried out three days per month from January to May 2017. A total of 1028 flies were caught among which 49.61% of them belonged to the family Stomoxyidae, Tabanidae (34.63%) and Glossinidae (15.76%). Fourteen species were caught and grouped under the following genera: Glossina (02), Stomoxys (04), but Tabanidae was represented by three genera: Tabanus consisting of three species, Chrysops (03) and Haematopota (2) with the genus Tabanus highly represented. Glossina, Stomoxys and Chrysops were abundant in the rainy season while Tabanus and Haematopota were abundant in the dry season. 50.88% of the catches were from the Vavoua trap, followed by Nzi (39.3%) and Biconical (9.2%).
Abstract: The objective of this work was to evaluate the diversity and composition of glossines, tabanids and stomoxes in the dry and rainy seasons at the Douala-Edéa Game Reserve (DEGR) using Biconical, Vavoua and Nzi traps. Three traps i.e. one of each type was pitched in the sampled sites with collection carried out three days per month from January to Ma...
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Blood Feeding Preference of Female Aedes aegypti Mosquitoes for Human Blood Group Types and Its Impact on Their Fecundity: Implications for Vector Control
Manushika Prasadini,
Dilakshini Dayananda,
Sachini Fernando,
Iresha Harischandra,
Nissanka De Silva
Issue:
Volume 3, Issue 2, June 2019
Pages:
43-48
Received:
18 May 2019
Accepted:
13 June 2019
Published:
26 June 2019
Abstract: Aedes aegypti is the major vector of Dengue in Sri Lanka. Dengue virus is transmitted via blood feeding of vector mosquitoes. Blood is an essential component for the fecundity of mosquitoes and the knowledge on feeding behaviour of Ae. aegypti is important in dengue prevention measures. Therefore, the study was designed to identify the preferential feeding of Ae. aegypti on human ABO blood groups and their impacts on fecundity. Laboratory reared female Ae. aegypti mosquitoes were exposed to all four blood groups at once in separate membrane feeders. After feeding, DNA of blood in mosquitoes was extracted and identified using ABO genotyping PCR. Fecundity was determined by the mean number of eggs in an egg batch. The highest preference was observed for the blood group “O” (P<0.05; 0.00). The mean number of egg production of each blood group was not significantly different showing no impact on the blood type for the fecundity. This study reports for the first time that there is no direct impact of the preferred blood group on the fecundity of Ae. aegypti female mosquitoes. Furthermore, preference of blood group selection by female mosquitoes would be highly important in personal protection measures against mosquito bites, as the personal protection is one of the most effective control measures for prevention of Dengue.
Abstract: Aedes aegypti is the major vector of Dengue in Sri Lanka. Dengue virus is transmitted via blood feeding of vector mosquitoes. Blood is an essential component for the fecundity of mosquitoes and the knowledge on feeding behaviour of Ae. aegypti is important in dengue prevention measures. Therefore, the study was designed to identify the preferential...
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Influence of Plant Spacing on Insect Population, Growth and Yield of Okra in Sierra Leone
Johnny Ernest Norman,
Dan David Quee,
Philip Jimia Kamanda,
Alusaine Edward Samura
Issue:
Volume 3, Issue 2, June 2019
Pages:
49-55
Received:
18 April 2019
Accepted:
13 June 2019
Published:
9 July 2019
Abstract: Okra is a very important vegetable in the field of nutrition and health care in Sierra Leone. The major limiting factors in okra production are incidence of insect pests and improper plant spacing. The present field research was undertaken at the Department of Crop Protection, School of Agriculture, Njala University to evaluate the effect of plant spacing on insect pest population, growth and yield, and profitability of okra production in Sierra Leone from 2017 to 2018 main cropping seasons. Five levels of plant spacing 50 cm × 40 cm (50,000 plants per hectare), 60 cm × 30 cm (55,556 plants per hectare), 60 cm × 40 cm (41,667 plants per hectare), 70 cm × 30 cm (47,619 plants per hectare), and 70 cm × 40 cm (35,714 plants per hectare) were adopted as treatments with three replications in randomized complete block design. The results of analysis of variance revealed that plant spacing were significant (P < 0.05) on insect population, plant height, leaf area, damage leaves, yield and yield components of okra at 4 and 8 weeks after planting (WAP) during 2017 and 2018 main cropping seasons. Okra cropped in plant spacing 50 cm x 40 cm (Recommended rate) inclined the highest number of insects, plant height, leaf area, damage leaves and yield at 4 and 8 WAP in both years followed by 60 cm x 40 cm plant spacing, while the reverse also holds true with 70 cm x 40 cm plant spacing. The profitability analysis revealed that the recommended plant spacing of okra (50 cm x 40 cm) produced the highest gross margins of Le 18,333,000.00 plants per hectare (ha-1) and Le 21,363,000 plants per hectare (ha-1) respectively during 2017 and 2018 main cropping seasons of okra production. In conclusion, increasing the plant spacing above the recommended plant spacing (50 cm x 40cm) could reduce insect population and leaf damage on okra, but will significantly decrease okra growth and yield, and profitability. Hence, in order to achieve maximum productivity of okra in the Njala area, the Clemson spineless variety of okra should be planted at a plant spacing of 50 cm x 40 cm. However, integrating plant spacing with other cultural methods of controlling insect pests of okra should be investigated in order to determine a sustainable and cost-effective method of controlling insect pests of okra.
Abstract: Okra is a very important vegetable in the field of nutrition and health care in Sierra Leone. The major limiting factors in okra production are incidence of insect pests and improper plant spacing. The present field research was undertaken at the Department of Crop Protection, School of Agriculture, Njala University to evaluate the effect of plant ...
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