scholarly journals Efficacy of Ricinus communis L., Cassia occidentalis L. and Bacillus thuringiensis against Helicoverpa armigera Hübner (Lepidoptera: Noctuidae)

2021 ◽  
Vol 3 (3) ◽  
pp. 46-53
Author(s):  
Waleed Elamin Elhaj ◽  
Abdelgadir Ahmed Osman ◽  
Loai Mohamed Elamin Elawad

Helicoverpaarmigera is one of the most destructive pests of field crops worldwide. The Study was designed to investigate through laboratory screening the insecticidal activity of Ricinus communis, Cassia occidentalis and Bacillus thuringiensis var. Kurstaki (Btk) and their combinations against 2nd larval instar of H. armigera. Five concentrations (4%, 6%, 8%, 10% and 12%) of each plant extract and (0.62, 1.25, 2.5, 5, and 10 mg/ml) of Bt were used in this experiment. Mortality (%) was recorded after 24,48,72 and 96 hrs post treatment. The results showed that R. communis, C. occidentalis and Btkhave insecticidal activity against 2nd instar larvae of H. armigera. The highest concentration (12%) caused 80% and 70% larval mortality after 96 hrs for R. communis and C. occidental respectively. The statistical analysis revealed that there is a significant differences between all treatments and control. Additionally, all combinations (plant/plant or plant/Bt) increased the mortality %. The results also clearly demonstrate that the R. communis are significantly more toxic than C. occidental where the LC50 values were 6.4 % for R. communis and 8.1% for C. occidental. On the other hand LC50 value for Bt was 0.41 mg/ml. The binary mixture of R. communis and C. occidental have a potentiation effect after 48 hrs. Regarding the mixture of Bt and plant extracts the results revealed that R. communis and Bt mixture induced a potentiation effect whereas C. occidental and Bt mixture induced a an additive effects.

2010 ◽  
Vol 11 (1) ◽  
pp. 41 ◽  
Author(s):  
Edgar Herney Varón ◽  
Márcio Dionizio Moreira ◽  
Jenny Paola Corredor

<p>El chinche de encaje, Corythucha gossypii (Fabricius) (Hemiptera: Tingidae), es un insecto plaga del algodón, pero ha sido reportado en más de veinticuatro hospederos, incluyendo higuerilla (Ricinus communis L). El objetivo de este trabajo fue evaluar si esta plaga disminuye el periodo de vida útil de las hojas, establecer la superficie de muestreo de la hoja que mejor representa las poblaciones de esta plaga y la eficacia de seis insecticidas para su control en higuerilla. La vida útil de las hojas fue negativamente influenciada por la presencia del insecto plaga; a mayor número inicial de insectos, menor fue el tiempo para la pérdida de hojas. La superficie del envés fue la que mejor representó la población de C. gossypii con un promedio ± Error Standard (ES) de 55,10 ± 4,76 de individuos y una correlación con la población total de 99,60%, R2 =0,99 y p &lt; 0,0001; comparado con 3,44 ± 0,57 individuos y una correlación de 66,32%; R2=0,44 y p &lt; 0,0001 para la superficie del haz. El orden de eficacia de control para 3 días después de la aplicación de los tratamientos fue tiametoxam + lambdacihalotrina (0,00%), spinetoram, (0,00%), malation (20,35%), tiametoxam (38,62%), dimetoato (86,94%) e imidacloprid (87,33%); para 7 días fue tiametoxam + lambdacihalotrina (0,00%), spinetoram (21,46%), malation (38,77), tiametoxam (50,84%), dimetoato (86,14%) e imidacloprid (90,37%). Los datos de muestreo, a partir de 16 días, presentaron una gran pérdida de unidades experimentales, lo que imposibilitó el análisis de los resultados, después de ese tiempo.</p><p> </p><p><strong>Effect of Corythucha gossypii on Castor Oil Plant Leaves: Sampling Criteria and Control by Insecticides</strong></p><p>The lace bug, also called the “cotton or bean lace bug”, Corythucha gossypii (Fabricius) (Hemiptera: Tingidae) is a common pest from cotton. However it has been reported in another twenty four plant hosts including castor bean (Ricinus communis L.). This work aimed to establish if this insect pest can reduce the life-period of leaves, to assess which is the leaf surface that best represents the total pest population for sampling and to test the efficacy of six insecticides for C. gossypii control in a castor bean crop. The life-period of leaves was negatively affected by the presence of the insect, the larger the number of C. gossypii, the shorter their leaf life. The lower surface best represented the entire population of lace bug with a mean ± standard error of 55.10 ± 4.76, with a 99.60% of correlation, a R2=0.99 and a p &lt; 0.0001; compared to 3.44 ± 0.57, with a 66.32% of correlation, a R2=0.44 and a p &lt; 0.0001 for the upper surface. Efficacy of control after three days of insecticide application was: thiamethoxam + lambdacyhalothrin (0.00%), spinetoram, (0.00%), malathion (20.35%), thiamethoxam (38.62%), dimethoate (86.94%) and imidacloprid (87.33%). After seven days of insecticide application the efficacy was thiamethoxam + lambdacyhalothrin (0.00%), spinetoram (21.46%), malathion (38.77), thiamethoxam (50.84%), dimethoate (86.14%) and imidacloprid (90.37%). Results obtained after 16 days lacked many sampling unit leaves, which made their analysis meaningless, after that period of time. </p>


2014 ◽  
Vol 81 (4) ◽  
pp. 329-334 ◽  
Author(s):  
Alciani da Silva Pessoa ◽  
Everton Ricardi Lozano ◽  
Andréia Vilani ◽  
Michele Potrich ◽  
Lísia de Lima Matos ◽  
...  

O objetivo deste trabalho foi avaliar o efeito de extratos vegetais aquosos de jambolão, Syzygium cumini (L.) Skeels (Myrtaceae), mamona, Ricinus communis (L.) (Euphorbiaceae), uva-do-japão, Hovenia dulcis (Thumberg) (Rhamnaceae) e urucum (Bixa orellana (L.) (Bixaceae), na concentração de 10%, sobre Bacillus thuringiensis subesp. kurstaki(Btk) e sobre Anticarsia gemmatalis (Lepidoptera: Erebidae) e a associação destes sobre A. gemmatalis, em condições de laboratório. Os tratamentos constaram dos extratos aquosos e Btk isoladamente e a mistura de cada extrato com Btk. Estes foram incubados em agitador horizontal (30 ± 2°C, 150 rpm por 2 h) e, em seguida, aplicados sobre cubos de dieta artificial para A. gemmatalis, em placas de Petri. Como testemunha utilizou-se água destilada esterilizada. Cada tratamento constou de 4 placas de Petri (repetição), com 25 lagartas de segundo ínstar cada. Estas foram acondicionadas em câmara climatizada (27 ± 2°C umidade relativa 70 ± 10% e fotofase 14 h), avaliando-se a mortalidade após 24, 48 e 72 h. Também foram avaliados o percentual de empupamento e o peso das pupas dos insetos sobreviventes. Nenhum dos extratos apresentou efeito inseticida para A. gemmatalis e efeito negativo para os cristais de Btk. A mortalidade acumulada causada pelos extratos de uva-do-japão, jambolão, urucum e mamona foram, respectivamente, de 54,73; 46,09; 47,19 e 65,73%; diferindo significativamente da testemunha (95,74%). O peso médio das pupas não diferiu significativamente entre os tratamentos. A associação dos extratos de uva-do-japão, colorau e mamona com Btk provocou mortalidade acumulada de 100% em A. gemmatalis.


2001 ◽  
Vol 36 (1) ◽  
pp. 23-33 ◽  
Author(s):  
Muhammad Ashfaq ◽  
S. Y. Young ◽  
R. W. McNew

Larval mortality, survivorship and movement of the bollworm, Helicoverpa zea (Boddie), on and away from Bacillus thuringiensis-treated cotton leaves were investigated in the laboratory. Bacillus thuringiensis (Costar®, Novartis Crop Protection, Inc; Greensboro, NC) was applied to the upper surface of cotton leaves via a spray table in five concentrations, i.e., 0.0 (control), 0.14, 0.29, 0.58, and 1.15 kg/ha. Three-day-old H. zea larvae were released on treated leaves, kept at 30°C, and transferred to artificial diet after 12, 24, and 48 h. Significantly higher numbers of larvae were found on the lower than upper leaf surface after all three transfer times, but the numbers surviving in all treatments were similar to the control. Larval movement from the leaf to cup surface was significantly higher in B. thuringiensis-treated leaves than in the control. The mortality of larvae that were transferred from leaves to diet at 7 d after treatment was significantly higher in all treatments than in the control and highest at the highest rates (0.58 and 1.15 kg/ha). Data on survival of larvae at different locations suggest that for the first 24 h, the increase in the percentage of larvae on the inner cup surface in B. thuringiensis treatments was not due to larvae that had consumed a lethal dose, but an attempt to avoid the B. thuringiensis on the upper leaf surface. Highest larval weight was recorded in the control for all transfer times. The length of the larval period increased with the B. thuringiensis rate at the 12-h transfer. The pupal weight was reduced at the highest B. thuringiensis rates at the 48-h transfer.


2005 ◽  
Vol 82 (2) ◽  
pp. 73-82 ◽  
Author(s):  
J.-C. Côté ◽  
C. Vincent ◽  
K.-H. Son ◽  
S. H. Bok

DiPelTM, a registered Bacillus thuringiensis var. kurstaki (Btk)-based formulation, and experimental bio-encapsulated Btk formulations were sprayed in an apple orchard. Their persistence was assessed in the laboratory against obliquebanded leafroller (Choristoneura rosaceana) larvae for three consecutive years. In 1995, DiPel and the bio-encapsulated formulation caused significantly higher larval mortality than the control at least 1 day, and up to 27 days after treatments, respectively. In 1996, although 6.4 mm of rain fell during the day of treatments, DiPel and the bio-encapsulated formulation caused respectively 21 and 33% larval mortality immediately after treatments. DiPel caused significantly higher mortality than the control for up to 3 days while the bio-encapsulated formulation caused significantly higher mortality for up to 14 days. In 1997, two Btk strains (HD-1 and BMP123) were sprayed at different concentrations in a.i. (3 and 8%) and doses (30 and 240 g 15 L-1 applied). Higher concentrations of a.i. in the Btk formulations and higher doses sprayed increased the persistence of the insecticidal activity. Among the meteorological factors that were measured (i.e. precipitations, temperature and solar radiations), precipitations reduced the persistence of the insecticidal activity. Solar radiations may have modulated the persistence of the formulations.


Author(s):  
Jyoti Limbu ◽  
Bijay Kumar Shrestha ◽  
Jenish Shakya ◽  
Sabin Bahadur Khatri ◽  
Hemanta Khanal

Bacillus thuringiensis (Bt) synthesize a large diversity of crystal proteins (Cry and Cyt) during sporulation which exhibit insecticidal activity against insects and protozoa. The main aim of this study was to isolate Bacillus thuringiensis and study its insecticidal effect against Galleria mellonella. Soil samples from four different geographical locations of Koshi Zone viz. Itahari, Tarhara, Dharan and Vedetar of Eastern Nepal were collected. The isolation of Bt was done by acetate selection method. The insect bioassay of Bt isolates were performed against greater wax moth (G. mellonella) by feeding the third instar larvae by extracted crystal spores with three different concentrations. The overall distribution of Bt from the study sample was found to be 30% (30/100). Bt was isolated from all four geographical location with higher incidence; 9 (36%) in Tarhara region followed by Dharan (32%), Itahari (28%) and Vedetar (24%). However, the incidence of Bt with potent insecticidal activity against G. mellonella was reported to be 4% (4/100). The insecticidal activity of isolated Bt between test and control groups was found to be statistically significant (p<0.05). LC50 value of Bt from Tarhara (Tar1) was 388.29μg/mL, Dharan; Drn8 and Drn1 was 416.20μg/mL and 463.15μg/mL respectively and from Vedetar (Vd5) was 476.63μg/mL. In overall study the Bt isolated from Tarhara (Tar1) region exhibited greater incidence, Bt index, efficacy and effective level of LC50 against greater wax moth. Native Bt strains isolated from soil of Eastern Nepal possess effective insecticidal activity and hence can used as biocontrol agent in controlling honeycomb pest like G. mellonella.


2000 ◽  
Vol 35 (2) ◽  
pp. 105-117 ◽  
Author(s):  
C. D. Parker ◽  
V. J. Mascarenhas ◽  
R. G. Luttrell ◽  
K. Knighten

The insecticidal activity of transgenic cottons expressing endotoxin protein of Bacillus thuringiensis Berliner (Bt cotton) was quantified by measuring survival of tobacco budworm, Heliothis virescens (F.), larvae caged on different plant structures for varying lengths of exposure. Percentages of larvae surviving were measured on Bt cottons expressing Cry1Ab and CrylAc protein. Plant structure (terminal, leaf, square or boll) did not affect larval survival, and survival did not differ significantly between CrylAb and CrylAc cottons. Larvae exposed to Bt cotton for only 24 h had higher initial survival than larvae exposed for 48, 72 and 96 h. Larvae first exposed to Bt cotton at 4 d of age had higher survival than those first exposed as neonate or 2-d-old larvae. Survivorship of neonate and 4-d-old larvae exposed to CrylAc cotton was significantly reduced with only 48 h of exposure to the insecticidal plants. Seven-day-old larvae exhibited no significant reduction in survivorship with exposure to CrylAc cotton for 48 h.


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