1,720,974 research outputs found
Efficacy and acceptability of neem (Azadirachta indica A. Juss) seed oil and pirimiphos-methyl applied in three storage devices for the control of Callosobruchus maculatus (F.) (Coleoptera : Bruchidae)
No full textThe efficacy of four dosages (25, 50, 75 and 100 mg) of neem seed oil applied separately in 0.2 mi of analytical grade of acetone to four replicates of 20 g of cowpea seeds in reducing the reproductive potential of Callosobruchus maculatus was evaluated in th ree storage devices (two unventilated and one ventilated) over a 3-month period. These were compared with untreated cowpea seeds and seeds created with pirimiphos-methyl (Actellic 25 EC) applied at the recommended race of 175 mg a. i./kg (3.5 mg a. i./20 g seed). There was no significant difference in the efficacy of neem seed oil (NSO) and pirimiphos-methyl (PMM) in reducing oviposition, adult emergence or seed damage in treated cowpeas stored in the three devices. The dosages of NSO significantly reduced oviposition and adult emergence. No adult emerged in PMM-treated seeds. At the dosages of 75 and 100 mg/20 g seed, NSO completely suppressed adult emergence in the second and third generations of C. maculatus. Percentage of damaged seeds ranged from 0.6 % in the first month of storage to 3.4 % in the third month in NSO-treated seeds and from 8.3 % in the first month to 100 % in the third month in untreated seeds. No damage occurred in PMM-treated seeds. Treatment with NSO or PMM imparted strong objectionable flavour and aroma to cooked cowpea seeds
Mortality of different developmental stages of Callosobruchus maculatus F. and Callosobruchus subinnotatus Pic. (Coleoptera : Bruchidae) in bambara groundnut Vigna subterranea (L.) Verdc. seeds exposed to simulated solar heat
No full textThe susceptibility of Callosobruchus maculatus F. and Callosobruchus subinnotatus Pie. eggs, first and late instar larvae as well as adults to the lethal effect of solar heat of a temperature of 50 degreesC simulated in an incubator was evaluated. Development of adult progeny was completely suppressed in both species in bambara groundnut seeds bearing I-day-old eggs or harboring first instar lan ae exposed for 4 or 6 h to this temperature. Suppression of adult progeny development was due to the fact that this level of heat caused 100 % mortality of these developmental stages of the bruchids. In C. maculatus, 100 % mortality occurred in first instar larvae exposed for 2 h while in C. subinnotatus, 100% mortality occurred in eggs and first instar Larvae exposed for a similar duration. In addition, adults of both species that were exposed for 25 min, and in the case of C, maculatus adults exposed for 20 min as well, sustained 100 % mortality. On average, C. maculatus adults with a mortality figure of 50.7 % were more susceptible to the lethal effect of this level of heat than C. subinnotatus adults with a mortality figure of 37.0 %. Solar heat could be used as :Ln inexpensive method for control of these pest species in developing countries
Efficacy and acceptability of neem (Azadirachta indica A. Juss) seed oil and pirimiphos-methyl applied in three storage devices for the control of Callosobruchus maculatus (F.) (Coleoptera : Bruchidae)
No full textThe efficacy of four dosages (25, 50, 75 and 100 mg) of neem seed oil applied separately in 0.2 mi of analytical grade of acetone to four replicates of 20 g of cowpea seeds in reducing the reproductive potential of Callosobruchus maculatus was evaluated in th ree storage devices (two unventilated and one ventilated) over a 3-month period. These were compared with untreated cowpea seeds and seeds created with pirimiphos-methyl (Actellic 25 EC) applied at the recommended race of 175 mg a. i./kg (3.5 mg a. i./20 g seed). There was no significant difference in the efficacy of neem seed oil (NSO) and pirimiphos-methyl (PMM) in reducing oviposition, adult emergence or seed damage in treated cowpeas stored in the three devices. The dosages of NSO significantly reduced oviposition and adult emergence. No adult emerged in PMM-treated seeds. At the dosages of 75 and 100 mg/20 g seed, NSO completely suppressed adult emergence in the second and third generations of C. maculatus. Percentage of damaged seeds ranged from 0.6 % in the first month of storage to 3.4 % in the third month in NSO-treated seeds and from 8.3 % in the first month to 100 % in the third month in untreated seeds. No damage occurred in PMM-treated seeds. Treatment with NSO or PMM imparted strong objectionable flavour and aroma to cooked cowpea seeds
Mortality of different developmental stages of Callosobruchus maculatus F. and Callosobruchus subinnotatus Pic. (Coleoptera : Bruchidae) in bambara groundnut Vigna subterranea (L.) Verdc. seeds exposed to simulated solar heat
No full textThe susceptibility of Callosobruchus maculatus F. and Callosobruchus subinnotatus Pie. eggs, first and late instar larvae as well as adults to the lethal effect of solar heat of a temperature of 50 degreesC simulated in an incubator was evaluated. Development of adult progeny was completely suppressed in both species in bambara groundnut seeds bearing I-day-old eggs or harboring first instar lan ae exposed for 4 or 6 h to this temperature. Suppression of adult progeny development was due to the fact that this level of heat caused 100 % mortality of these developmental stages of the bruchids. In C. maculatus, 100 % mortality occurred in first instar larvae exposed for 2 h while in C. subinnotatus, 100% mortality occurred in eggs and first instar Larvae exposed for a similar duration. In addition, adults of both species that were exposed for 25 min, and in the case of C, maculatus adults exposed for 20 min as well, sustained 100 % mortality. On average, C. maculatus adults with a mortality figure of 50.7 % were more susceptible to the lethal effect of this level of heat than C. subinnotatus adults with a mortality figure of 37.0 %. Solar heat could be used as :Ln inexpensive method for control of these pest species in developing countries
Potential of varietal resistance and Piper guineense seed oil to control infestation of stored millet seeds and processed products by Tribolium castaneum (Herbst)
No full textThree grain forms (whole grains, broken grains and wholemeal flour) of three improved varieties (ICMV-N89305, GB8735 and Sosat) developed at ICRISAT (Patancheru, India), one cultivar which originated in Zimbabwe (Zimbabwean dwarf) and two local cultivars (Ex-borno and Gwagwa), of pearl millet were compared for their susceptibility to the rust-red flour beetle (Tribolium castaneum) under tropical storage conditions. The biological effects of Piper guineense seed oil were also investigated on T. castaneum confined on similar forms of millet (Ex-borno) contained in ventilated or unventilated devices. Mortality of adult flour beetles was significantly higher on whole grains of GB8735 (99.7%), Gwagwa (92.3%) and Ex-borno (77.7%) stored in unventilated glass jars than on whole grains of Zimbabwean dwarf (52.7%) stored in a similar device. The number of adult progeny was significantly higher in wholemeal flour than in broken grains; the number in broken grains was significantly higher than that in whole grains. Development of the beetle was significantly longer in GB8735 than in Zimbabwean dwarf and the overall susceptibility of Zimbabwean dwarf was significantly higher than that of ICMV-N89305. Susceptibility of the cultivars increased with decreasing grain particle size; susceptibility indices for the whole grains, broken grains and wholemeal flour were 2.52, 12.14 and 14.16, respectively. Significantly fewer beetles developed in grains/products treated with P. guineense seed oil than in untreated grains/products. The unventilated glass jar retained the biological efficacy of the two lower dosages (20 and 40 mg/10 g) of P. guineense seed oil significantly more than the ventilated clay pot or polypropylene sack. (C) 2000 Elsevier Science Ltd. All rights reserved
Suppressing infestation of stored pearl millet Pennisetum glaucum (L.) R. Br. by Tribolium castaneum (Herbst) with insecticidal essential oils in Maiduguri, Nigeria
No full textThe insecticidal, larvicidal and antibiotic effects of three essential oils obtained from clove (Syzgium aromaticum (L.) Merr. er L. M. Perry), West African black pepper (WABP) (Piper guineense Schumach. er Thonn.) and ginger (Zingiber officinale Rosc.) were evaluated against the rust-red flour beetle, Tribolium castaneum (Hbst.), infesting stored pearl miller in Maiduguri, Nigeria. Clove or WABP oil was significantly more toxic to adults and larvae of T: castaneum than ginger oil. At the dosage of 100 mg/5 g seed, clove, WABP and ginger oils caused 96.3, 100 and 13.2 % adult mortalities, respectively, and 65.7, 83.4 and 9.6 % larval mortalities, respectively. Application of-clove or WABP oil at the rare of 80 mg/5 g seed completely suppressed the development of T. castaneum adults and larvae in miller grains
Potential of varietal resistance and Piper guineense seed oil to control infestation of stored millet seeds and processed products by Tribolium castaneum (Herbst)
No full textThree grain forms (whole grains, broken grains and wholemeal flour) of three improved varieties (ICMV-N89305, GB8735 and Sosat) developed at ICRISAT (Patancheru, India), one cultivar which originated in Zimbabwe (Zimbabwean dwarf) and two local cultivars (Ex-borno and Gwagwa), of pearl millet were compared for their susceptibility to the rust-red flour beetle (Tribolium castaneum) under tropical storage conditions. The biological effects of Piper guineense seed oil were also investigated on T. castaneum confined on similar forms of millet (Ex-borno) contained in ventilated or unventilated devices. Mortality of adult flour beetles was significantly higher on whole grains of GB8735 (99.7%), Gwagwa (92.3%) and Ex-borno (77.7%) stored in unventilated glass jars than on whole grains of Zimbabwean dwarf (52.7%) stored in a similar device. The number of adult progeny was significantly higher in wholemeal flour than in broken grains; the number in broken grains was significantly higher than that in whole grains. Development of the beetle was significantly longer in GB8735 than in Zimbabwean dwarf and the overall susceptibility of Zimbabwean dwarf was significantly higher than that of ICMV-N89305. Susceptibility of the cultivars increased with decreasing grain particle size; susceptibility indices for the whole grains, broken grains and wholemeal flour were 2.52, 12.14 and 14.16, respectively. Significantly fewer beetles developed in grains/products treated with P. guineense seed oil than in untreated grains/products. The unventilated glass jar retained the biological efficacy of the two lower dosages (20 and 40 mg/10 g) of P. guineense seed oil significantly more than the ventilated clay pot or polypropylene sack. (C) 2000 Elsevier Science Ltd. All rights reserved
Effect of weevil infestation on the caffeine content of stored kolanuts (Cola nitida Schott Vent. et Endl.) in Maiduguri, Nigeria
No full textAn assessment uf the effect of weevil infestation on the caffeine content of red and white cultivars of kolanut. Cola nitida (Vent). Schott et Endl., was carried our in Maiduguri, northeastern Nigeria. Caffeine content was determined by a modification of the methylene chloride-water system method. Results showed significant decreases in the amount of caffeine with increasing levels of infestation, being 8.0 g/kg for uninfested kolanut, 6.5 g/kg For the mildly infested, 6.7 g/kg for the moderately infested, and 4.8 g/kg for the heavily infested. There was no significant difference between the caffeine content of the red and white kolanut cultivars at the two lower levels of infestation. Caffeine content was, however, significantly reduced in kolanuts that were heavily infested with weevils, especially in the red cultivar. Mean reductions in caffeine content ranged from 8.8 to 62.6 % in the red cultivar and from 18.8 to 25 % in the white cultivar
Efficacy of host plant resistance, sowing date modification and intercropping as methods for the control of Pachnoda interrupta (Olivier) in pearl millet in the Nigerian Sudan savanna
No full textThree experiments were conducted in 1997 and repeated in 1998 cropping seasons in Maiduguri, Nigeria to assess damage caused by the scarab beetle, Pachnoda interrupta (Olivier) (Coleoptera: Scarabaeidae), in six Varieties (Ex-borno, Wame, Zongori, Gargasori, Mboderi and GB8735) of pearl millet sown as sole crops on 14, 21, 28 July and 5 August and as mixed crops with cowpea (var. Borno brown) or sorghum (var. Gooseneck). Damage in the local variety (Ex-borno) of pearl millet sown as a mixed crop with cowpea or sorghum in cropping patterns of 3:1, 2:1, 1:1 and 1:0 was also assessed. Damage and grain yield loss were significantly higher in millet sown on or before 21 July than in those sown later in both 1997 and 1998 cropping seasons; grain yields were, however, significantly higher in millet sown on 14 July or 5 August in 1997 and in millet sown on or before 28 July 1998. Damage and grain yield loss were significantly higher in GB8735 but lower in Gargasori in both years while grain yields were significantly higher in Wame in 1997 and in Gargasori in 1998 than in GB8735. The highest grain yields were obtained from Zongori sown on or before 21 July in 1997 and 1998. Damage and grain yield loss were significantly lower in the millet-sorghum intercrop than in the other cropping systems in 1998; grain yields were significantly higher in sole millet intercrop but lower in millet-sorghum than in the other systems in 1997. Damage and grain yield loss were significantly higher in GB8735 in both years and lower in Gargasori in 1998. The highest grain yields were obtained from sole Zongori in 1997 and Zongori-sorghum intercrop in 1998. Damage was significantly lower in the 1:1 cropping pattern than in the other patterns in 1998. Grain yields were significantly higher in the 1:0 cropping pattern but lower in the 1:1 pattern than in the other patterns in 1997. Similarly, grain yields were higher in the millet-cowpea than in the millet-sorghum intercrop in 1997. (C) 2000 Academic Press
Suppressing infestation of stored pearl millet Pennisetum glaucum (L.) R. Br. by Tribolium castaneum (Herbst) with insecticidal essential oils in Maiduguri, Nigeria
No full textThe insecticidal, larvicidal and antibiotic effects of three essential oils obtained from clove (Syzgium aromaticum (L.) Merr. er L. M. Perry), West African black pepper (WABP) (Piper guineense Schumach. er Thonn.) and ginger (Zingiber officinale Rosc.) were evaluated against the rust-red flour beetle, Tribolium castaneum (Hbst.), infesting stored pearl miller in Maiduguri, Nigeria. Clove or WABP oil was significantly more toxic to adults and larvae of T: castaneum than ginger oil. At the dosage of 100 mg/5 g seed, clove, WABP and ginger oils caused 96.3, 100 and 13.2 % adult mortalities, respectively, and 65.7, 83.4 and 9.6 % larval mortalities, respectively. Application of-clove or WABP oil at the rare of 80 mg/5 g seed completely suppressed the development of T. castaneum adults and larvae in miller grains
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