This study determined the effects of initial infestation of cowpea seeds （Ife brown variety） with different insect densities （0, 2, 4 and 6 pairs per 50 g seeds） of Callosobruchus maculatus （F.） and evaluated th...This study determined the effects of initial infestation of cowpea seeds （Ife brown variety） with different insect densities （0, 2, 4 and 6 pairs per 50 g seeds） of Callosobruchus maculatus （F.） and evaluated the effects of aqueous leaf extract of Nicotiana tabacum L. on C. maculatus in the laboratory. It was observed that adult beetle population increased significantly （p〈0.05） with increase in insect density. The increase in population of beetles and corresponding weight loss of the seeds in different levels of infestation showed that the cowpea variety was susceptible to beetle infestation, emergence and survival of progeny. Significantly more adults emerged on higher infestation compared to lower and no infestation. In Nigeria, Nicotiana tabacum L. is a locally available plant, with known insecticidal properties. The plant leaf extract was easily extracted with water and confirmed its effectiveness as a protective agent for stored cowpea seeds. Experiment was conducted to assess the effects of aqueous extracts ofN. tabacum at 0, 0.1, 0.2 and 0.3 mL＂ 50 g-1 cowpea seeds on C. maculatus. Data was recorded and showed varying levels of effectiveness against C. maculatus. Result showed that seed appearance was dependent on levels of insect population, while N. tabacum aqueous extract exerted effects on survival of C. maculatus. Aqueous leaf extract of N. tabacum probably contained some insecticidal properties which might have significantly conferred beetle mortality and reduced beetle emergence leading to a decrease in seed weight loss.展开更多
An investigation of effect of Latana camara, Tephrosia vogelii and Zingiber officinale applied at 5%, 10% and 25% concentrations on flea beetle of cabbage was conducted on the Teaching and Research Farm of the Ladoke ...An investigation of effect of Latana camara, Tephrosia vogelii and Zingiber officinale applied at 5%, 10% and 25% concentrations on flea beetle of cabbage was conducted on the Teaching and Research Farm of the Ladoke Akintola University of Technology Ogbomoso in the early seasons of 2011 and 2012. The experiment consisted of 11 treatments laid in a Randomized Complete Block Design （RCBD） with three replications. Data were subjected to analysis of variance and significant means were compared using the Least Significant Difference （LSD） at p〈0.05. All the tested plant extracts exhibited moderate efficacy in the control of flea beetle. The treatment plant extracts performed as well as synthetic insecticides （0.76±0.05 and 0.76±0.05, respectively）. It was discovered that 25% w/v of Z. officinale gave the best yield of 0.50 kg · hm-2. The result showed that extract of T. vogelii （0.71±0.00） and L. camara （0.96±0.23） could suppress flea beetle population at different hours of spraying, while Z. officinale showed an effect at 48 HAS （0.71±0.00） and 72 HAS （0.76±0.05） alter spraying.展开更多
The insecticidal potential of seed powders of Capsicum chinense Jacq. （Solanaceae） and Aframomum melegueta K. Schum. （Zingiberaceae） was tested against Trogoderma granarium （Coleoptera： Dermestidae） in the labo...The insecticidal potential of seed powders of Capsicum chinense Jacq. （Solanaceae） and Aframomum melegueta K. Schum. （Zingiberaceae） was tested against Trogoderma granarium （Coleoptera： Dermestidae） in the laboratory at （28±2）℃ and 70%± 5% relative humidity. The seed powders were tested at the rates of 0.0%, 0.5%, 1.0% and 1.5% （w/w） of groundnut seeds replicated three times. At the highest rate of treatment, C. chinense caused 56.7% and 76.8% larval mortality at 3 and 7 days post treatment （DPT） respectively while A. melegueta exerted 53.4% and 73.8% larval mortality at 3 and 7 DPT, respectively. Results showed that insecticidal potential of the seed powders against adult mortality of T. granarium and seed damage followed similar trend. The various rates of C. chinense seed powder performed better than .4. melegueta seed powder in causing larval and adult mortality and in reducing seed damage. The activity of the seed powders on mortality of the insect, seed weight loss and seed damage were exposure time and rate dependent. A significant reduction （p〈0.05） in seed weight loss and seed damage was recorded among the treatments and maximum reduction was observed in the seeds treated with the highest rate of C. chinense seed powder. Percentage seed damage significantly （p〈0.05） decreased with increase in the rate of treatment while the highest seed weight loss and seed damage were obtained in the control. The study showed that C. chinense seed powder had higher activity against the test insect pest than .4. melegueta seed powder. The two seed powders had high bio-activity against the insect and therefore could be used in formulating environment friendly plant-derived insecticide.展开更多
A study was carried out to determine the relative susceptibility of six maize(Zea mays L.) varieties to maize weevil,Sitophilus zeamais Motschulsky(Coleoptera: Curculionidae). It was conducted at Department of Crop Pr...A study was carried out to determine the relative susceptibility of six maize(Zea mays L.) varieties to maize weevil,Sitophilus zeamais Motschulsky(Coleoptera: Curculionidae). It was conducted at Department of Crop Protection Laboratory,University of Ilorin, Nigeria at ambient temperature of 28±2℃ and 68%±3% relative humidity. Samples of the varieties were infestedwith five pairs of S. zeamais adults in their respective containers arranged in completely randomized design with three replications.Data were collected on moisture content, adult mortality, adult emergence, grain loss and grain damage. The index of susceptibilityand means of damage parameters were used to determine susceptibility of the maize varieties. The results showed that 2008 SYNEE W DT STR was highly resistant and 2004 TZE-W POP STR C4 was moderately resistant, while 2004 TZE-Y-POP STR C4,99 TZEE-Y-STR, EV99 QPM and TZE-Y-POP DT STR QPM C_0S1 were susceptible. Under artificial infestation, the weevils hadsignificantly longer survival period in the susceptible varieties than those in the resistant genotype. It could be concluded that thesusceptible varieties already released to farmers should be protected from maize weevil damage.展开更多
A laboratory experiment was carried out to determine the response of six groundnut varieties to infestation by larvae of Trogoderma granarium Everts （Coleoptera： Dermestidae） and their nutritional constituents. The...A laboratory experiment was carried out to determine the response of six groundnut varieties to infestation by larvae of Trogoderma granarium Everts （Coleoptera： Dermestidae） and their nutritional constituents. The improved groundnut varieties used included SAMNUT 10, RMP-91, SAMNUT 19, SAMNUT 23, EX-DAKAR and RRB. The crude fat content varied significantly among the varieties from 32.7% to 53.1% in EX-DAKAR and RRB, respectively. The seed varieties were not significantly different in crude protein, ash and moisture content. The moisture content ranged between 6.6% and 8.9% in EX-DAKAR and SAMNUT 19 varieties, respectively. The crude protein content ranged between 19.7% and 31.3% in SAMNUT 19 and EX-DAKAR, respectively. The ash content varied between 3.0% and 7.4% in RRB and RMP-91 varieties, respectively. The results showed that the seeds were attacked by the 4th instar larvae of T. granarium as indicated by percentage seed weight damage, seed weight loss and dust production. SAMNUT 10 variety had the least seed damage of 33.1%, 41.4% and 43.7% in 1 month, 2 and 3 months post-infestation. In view of the damage, it was evident that SAMNUT 10 variety had the least percent seed damage and loss suggesting the possible inclusion of the variety in breeding programme against the insect pest.展开更多
文摘This study determined the effects of initial infestation of cowpea seeds （Ife brown variety） with different insect densities （0, 2, 4 and 6 pairs per 50 g seeds） of Callosobruchus maculatus （F.） and evaluated the effects of aqueous leaf extract of Nicotiana tabacum L. on C. maculatus in the laboratory. It was observed that adult beetle population increased significantly （p〈0.05） with increase in insect density. The increase in population of beetles and corresponding weight loss of the seeds in different levels of infestation showed that the cowpea variety was susceptible to beetle infestation, emergence and survival of progeny. Significantly more adults emerged on higher infestation compared to lower and no infestation. In Nigeria, Nicotiana tabacum L. is a locally available plant, with known insecticidal properties. The plant leaf extract was easily extracted with water and confirmed its effectiveness as a protective agent for stored cowpea seeds. Experiment was conducted to assess the effects of aqueous extracts ofN. tabacum at 0, 0.1, 0.2 and 0.3 mL＂ 50 g-1 cowpea seeds on C. maculatus. Data was recorded and showed varying levels of effectiveness against C. maculatus. Result showed that seed appearance was dependent on levels of insect population, while N. tabacum aqueous extract exerted effects on survival of C. maculatus. Aqueous leaf extract of N. tabacum probably contained some insecticidal properties which might have significantly conferred beetle mortality and reduced beetle emergence leading to a decrease in seed weight loss.
文摘An investigation of effect of Latana camara, Tephrosia vogelii and Zingiber officinale applied at 5%, 10% and 25% concentrations on flea beetle of cabbage was conducted on the Teaching and Research Farm of the Ladoke Akintola University of Technology Ogbomoso in the early seasons of 2011 and 2012. The experiment consisted of 11 treatments laid in a Randomized Complete Block Design （RCBD） with three replications. Data were subjected to analysis of variance and significant means were compared using the Least Significant Difference （LSD） at p〈0.05. All the tested plant extracts exhibited moderate efficacy in the control of flea beetle. The treatment plant extracts performed as well as synthetic insecticides （0.76±0.05 and 0.76±0.05, respectively）. It was discovered that 25% w/v of Z. officinale gave the best yield of 0.50 kg · hm-2. The result showed that extract of T. vogelii （0.71±0.00） and L. camara （0.96±0.23） could suppress flea beetle population at different hours of spraying, while Z. officinale showed an effect at 48 HAS （0.71±0.00） and 72 HAS （0.76±0.05） alter spraying.
文摘The insecticidal potential of seed powders of Capsicum chinense Jacq. （Solanaceae） and Aframomum melegueta K. Schum. （Zingiberaceae） was tested against Trogoderma granarium （Coleoptera： Dermestidae） in the laboratory at （28±2）℃ and 70%± 5% relative humidity. The seed powders were tested at the rates of 0.0%, 0.5%, 1.0% and 1.5% （w/w） of groundnut seeds replicated three times. At the highest rate of treatment, C. chinense caused 56.7% and 76.8% larval mortality at 3 and 7 days post treatment （DPT） respectively while A. melegueta exerted 53.4% and 73.8% larval mortality at 3 and 7 DPT, respectively. Results showed that insecticidal potential of the seed powders against adult mortality of T. granarium and seed damage followed similar trend. The various rates of C. chinense seed powder performed better than .4. melegueta seed powder in causing larval and adult mortality and in reducing seed damage. The activity of the seed powders on mortality of the insect, seed weight loss and seed damage were exposure time and rate dependent. A significant reduction （p〈0.05） in seed weight loss and seed damage was recorded among the treatments and maximum reduction was observed in the seeds treated with the highest rate of C. chinense seed powder. Percentage seed damage significantly （p〈0.05） decreased with increase in the rate of treatment while the highest seed weight loss and seed damage were obtained in the control. The study showed that C. chinense seed powder had higher activity against the test insect pest than .4. melegueta seed powder. The two seed powders had high bio-activity against the insect and therefore could be used in formulating environment friendly plant-derived insecticide.
文摘A study was carried out to determine the relative susceptibility of six maize(Zea mays L.) varieties to maize weevil,Sitophilus zeamais Motschulsky(Coleoptera: Curculionidae). It was conducted at Department of Crop Protection Laboratory,University of Ilorin, Nigeria at ambient temperature of 28±2℃ and 68%±3% relative humidity. Samples of the varieties were infestedwith five pairs of S. zeamais adults in their respective containers arranged in completely randomized design with three replications.Data were collected on moisture content, adult mortality, adult emergence, grain loss and grain damage. The index of susceptibilityand means of damage parameters were used to determine susceptibility of the maize varieties. The results showed that 2008 SYNEE W DT STR was highly resistant and 2004 TZE-W POP STR C4 was moderately resistant, while 2004 TZE-Y-POP STR C4,99 TZEE-Y-STR, EV99 QPM and TZE-Y-POP DT STR QPM C_0S1 were susceptible. Under artificial infestation, the weevils hadsignificantly longer survival period in the susceptible varieties than those in the resistant genotype. It could be concluded that thesusceptible varieties already released to farmers should be protected from maize weevil damage.
文摘A laboratory experiment was carried out to determine the response of six groundnut varieties to infestation by larvae of Trogoderma granarium Everts （Coleoptera： Dermestidae） and their nutritional constituents. The improved groundnut varieties used included SAMNUT 10, RMP-91, SAMNUT 19, SAMNUT 23, EX-DAKAR and RRB. The crude fat content varied significantly among the varieties from 32.7% to 53.1% in EX-DAKAR and RRB, respectively. The seed varieties were not significantly different in crude protein, ash and moisture content. The moisture content ranged between 6.6% and 8.9% in EX-DAKAR and SAMNUT 19 varieties, respectively. The crude protein content ranged between 19.7% and 31.3% in SAMNUT 19 and EX-DAKAR, respectively. The ash content varied between 3.0% and 7.4% in RRB and RMP-91 varieties, respectively. The results showed that the seeds were attacked by the 4th instar larvae of T. granarium as indicated by percentage seed weight damage, seed weight loss and dust production. SAMNUT 10 variety had the least seed damage of 33.1%, 41.4% and 43.7% in 1 month, 2 and 3 months post-infestation. In view of the damage, it was evident that SAMNUT 10 variety had the least percent seed damage and loss suggesting the possible inclusion of the variety in breeding programme against the insect pest.
