Insecticidal effects of different doses of the dust and methanol extracts of Garcinia kolae on Callosobruchus maculatus and Sitophilus zeamais were tested. The dust had no significant effect on the two insects, none o...Insecticidal effects of different doses of the dust and methanol extracts of Garcinia kolae on Callosobruchus maculatus and Sitophilus zeamais were tested. The dust had no significant effect on the two insects, none of them died even at 3 d after treatment. The methanol extracts, however, had rapid lethal effects on both C. maculatus and S. zeamais. The mortality of C. maculatus by the lowest concentration of methanol extracts ranged from 95%-100% whereas in S. zeamais, the mortality ranged from 87.5%-100% and 70%-100% in concentrations of 1 g extract＋3 ml methanol and 1 g extract＋5 ml methanol, respectively, from 24 to 48 h. The least concentration of 1 g extract＋l 5 ml methanol had no significant lethal effect on Sitophilus zeamais.展开更多
The effect of four dried callus powders derived from certain plants, i.e. tomato, Lycopersicon esculentum; periwinkle, Catharanthus roseus; thorne apple, Datura stramonium and oleander, Nerium oleander applied separat...The effect of four dried callus powders derived from certain plants, i.e. tomato, Lycopersicon esculentum; periwinkle, Catharanthus roseus; thorne apple, Datura stramonium and oleander, Nerium oleander applied separately or concomitantly with oxamyl at a half of the recommended dose each on tomato seedlings grown in soil naturally heavy infested with M. incognita under field conditions, indicated that dried callus powder derived from N. oleander either alone or mixed with oxamyl significantly surpassed the other tested treatments in improving percentages of increase in whole plant fresh and shoot dry weights as well as increasing numbers and weights of fruits. Concerning other treatments including oxamyl at a half of recommended dose with each tested callus powder, similar results were evident regarding tomato plant growth parameters. C. roseus plus oxamyl achieved the highest percentage of increase in whole plant fresh weight （141.4%） and shoot dry weight （189.7%） and ranked second to N. oleander ＋ oxamyl in this respect over the untreated plants, respectively. One the other hand, among all tested materials single application of either L. esculentum or oxamyl gave the least values of such criteria which averaged 34.4% and 61.7% or 39.5% and 11.2%, respectively. All tested treatments significantly reduced the total number of galls, egg-masses and eggs in egg-masses especially, dried callus powder of N. oleander which applied singly or combined with oxamyl. The least values of reduction percentages of galls and eggs in egg-masses among all treatments were recorded from tomato plant received dried callus powders of L. esculentum applied alone or concomitant with oxamyl.展开更多
Bemisia tabaci is one of serious insect pests attacking vegetables and has been difficult to control using conventional insecticides. In the past 10 years, new insecticides have been introduced that provide a diversit...Bemisia tabaci is one of serious insect pests attacking vegetables and has been difficult to control using conventional insecticides. In the past 10 years, new insecticides have been introduced that provide a diversity of novel modes of action and routes of activity to effectively control whitefly. Consequently, intensive used of insecticides in vegetable cultivation has resulted in reduced susceptibility and develops resistance in agriculture industry. In controlling B. tabaci population, insecticides are the common method used by farmers. This study aimed to determine the most effective insecticide against B tabaci by using LC5o value. This study was conducted at the Crop Protection Laboratory, Faculty of Applied Science, Universiti Teknologi MARA Malaysia with the controlled room temperature of 24.33 ± 0.14℃ with dark and light ratio of 1：1 （12 hours： 12 hours） is an ideal condition for rearing the insect. The hypothesis of the study is to test if insecticides can control the nymph of whitefly. A total of 50 two-day-old nymphs were treated with insecticides using leaf-dip bioassay procedure. This experiment was replicated three times. The survival rates of the nymphs were analyzed using analysis of variance （ANOVA）. Data on toxicity was analyzed by a special Probit Programme-Single Line Analysis based on Finney （1971）. There was a significant difference （df = 8, F = 85.84, P = 0.000） in survival rate of nymph ofB. tabaci to eight insecticides tested. Among the insecticides tested, dimethoate, chlorpyrifos ＋ cypermethrin and diafenthiuron showed significantly higher survival rate of nymph compared to other treatments. When LC50 values were compared for diafenthiuron which is less potent （LCs0 ---- 2.44）, abamectin was found to be 3.44 times more potent than diafenthiuron, followed by esfenvalerate,acetamiprid, profenofos, chlorpyrifos ＋ cypermethrin and dimethoate, and the least potent was deltamethrin. The toxicity of eight insecticides tested against nymphs was in the following orders： abamectin = esfenvalerate = acetamiprid = profenofos =- chlorpyrifos ＋ cypermethrin ≥ dimethoate ≥ deltamethrin 〉 diafenthiuron respectively. This study implies that a proper application of the insecticide is a key component to a successful control programme of insect oests.展开更多
文摘Insecticidal effects of different doses of the dust and methanol extracts of Garcinia kolae on Callosobruchus maculatus and Sitophilus zeamais were tested. The dust had no significant effect on the two insects, none of them died even at 3 d after treatment. The methanol extracts, however, had rapid lethal effects on both C. maculatus and S. zeamais. The mortality of C. maculatus by the lowest concentration of methanol extracts ranged from 95%-100% whereas in S. zeamais, the mortality ranged from 87.5%-100% and 70%-100% in concentrations of 1 g extract＋3 ml methanol and 1 g extract＋5 ml methanol, respectively, from 24 to 48 h. The least concentration of 1 g extract＋l 5 ml methanol had no significant lethal effect on Sitophilus zeamais.
文摘The effect of four dried callus powders derived from certain plants, i.e. tomato, Lycopersicon esculentum; periwinkle, Catharanthus roseus; thorne apple, Datura stramonium and oleander, Nerium oleander applied separately or concomitantly with oxamyl at a half of the recommended dose each on tomato seedlings grown in soil naturally heavy infested with M. incognita under field conditions, indicated that dried callus powder derived from N. oleander either alone or mixed with oxamyl significantly surpassed the other tested treatments in improving percentages of increase in whole plant fresh and shoot dry weights as well as increasing numbers and weights of fruits. Concerning other treatments including oxamyl at a half of recommended dose with each tested callus powder, similar results were evident regarding tomato plant growth parameters. C. roseus plus oxamyl achieved the highest percentage of increase in whole plant fresh weight （141.4%） and shoot dry weight （189.7%） and ranked second to N. oleander ＋ oxamyl in this respect over the untreated plants, respectively. One the other hand, among all tested materials single application of either L. esculentum or oxamyl gave the least values of such criteria which averaged 34.4% and 61.7% or 39.5% and 11.2%, respectively. All tested treatments significantly reduced the total number of galls, egg-masses and eggs in egg-masses especially, dried callus powder of N. oleander which applied singly or combined with oxamyl. The least values of reduction percentages of galls and eggs in egg-masses among all treatments were recorded from tomato plant received dried callus powders of L. esculentum applied alone or concomitant with oxamyl.
文摘Bemisia tabaci is one of serious insect pests attacking vegetables and has been difficult to control using conventional insecticides. In the past 10 years, new insecticides have been introduced that provide a diversity of novel modes of action and routes of activity to effectively control whitefly. Consequently, intensive used of insecticides in vegetable cultivation has resulted in reduced susceptibility and develops resistance in agriculture industry. In controlling B. tabaci population, insecticides are the common method used by farmers. This study aimed to determine the most effective insecticide against B tabaci by using LC5o value. This study was conducted at the Crop Protection Laboratory, Faculty of Applied Science, Universiti Teknologi MARA Malaysia with the controlled room temperature of 24.33 ± 0.14℃ with dark and light ratio of 1：1 （12 hours： 12 hours） is an ideal condition for rearing the insect. The hypothesis of the study is to test if insecticides can control the nymph of whitefly. A total of 50 two-day-old nymphs were treated with insecticides using leaf-dip bioassay procedure. This experiment was replicated three times. The survival rates of the nymphs were analyzed using analysis of variance （ANOVA）. Data on toxicity was analyzed by a special Probit Programme-Single Line Analysis based on Finney （1971）. There was a significant difference （df = 8, F = 85.84, P = 0.000） in survival rate of nymph ofB. tabaci to eight insecticides tested. Among the insecticides tested, dimethoate, chlorpyrifos ＋ cypermethrin and diafenthiuron showed significantly higher survival rate of nymph compared to other treatments. When LC50 values were compared for diafenthiuron which is less potent （LCs0 ---- 2.44）, abamectin was found to be 3.44 times more potent than diafenthiuron, followed by esfenvalerate,acetamiprid, profenofos, chlorpyrifos ＋ cypermethrin and dimethoate, and the least potent was deltamethrin. The toxicity of eight insecticides tested against nymphs was in the following orders： abamectin = esfenvalerate = acetamiprid = profenofos =- chlorpyrifos ＋ cypermethrin ≥ dimethoate ≥ deltamethrin 〉 diafenthiuron respectively. This study implies that a proper application of the insecticide is a key component to a successful control programme of insect oests.
