Significant Reduction In Adult Emergence Research Articles

Effect of extract of Argemone mexicana L. seeds on the mortality, fecundity and emergence of Callosobruchus maculatus (F.) for the protection of the stored grains

Cowpea beetle, Callosobruchus maculates (Fabricius) (Coleoptera: Chrysomelidae: Bruchidae), is the most notorious store grain pest. Pulses constitute the major source of protein in most of the developing countries including India. The stored grain pests are difficult to control because of chemical insecticides if used causes health hazards to us. Adult C. maculates were exposed to 4, 8, 12 and 16ml concentration of extract/Kg grains of mung bean (Phaseolus aureus (Roxb) and were homogenized separately. After the treatment with acetone extract the mortality was recorded at 4ml concentration of extract per kg grains of mung bean, was observed i.e. 50%. The number of eggs laid were 115±5.00, grains infected were 109.33±3.21 and adult emerged were 98±3.00 respectively while at above 12 ml concentration of extract per kg grains of mung bean, the adult mortality was high i.e. 100%. There was no infestation and emergence of adults recorded. In chloroform and ethanol extracts of Argemone mexicana L seed the adult mortality was high 100%, there was no infestation and emergence of adult recorded at all concentrations per kg grain of mung bean. Methanol extract had very poor toxic effect and low inhibitory effect on the reproductive activity and hence, large number of the adults emerged out, they can damage the P. aureus grains severely in the forthcoming generations. As the concentration increases, significant reduction in adult emergence takes place. Seed extract of A. mexicana L. in acetone, chloroform and ethanol solvent shows highest mortality, no infestation and no adult emergence as compared with control while based on these findings, it can be used to control the infestation of stored grain pest C. maculatus F.

Cry75Aa (Mpp75Aa) Insecticidal Proteins for Controlling the Western Corn Rootworm, Diabrotica virgifera virgifera, (Coleoptera: Chrysomelidae), Isolated from the Insect Pathogenic Bacteria Brevibacillus laterosporus.

This study describes three closely related proteins, cloned from Brevibacillus laterosporus strains, that are lethal upon feeding to Diabrotica virgifera virgifera LeConte, the western corn rootworm (WCR). Mpp75Aa1, Mpp75Aa2 and Mpp75Aa3 were toxic to WCR larvae when fed purified protein. Transgenic plants expressing each mMpp75Aa protein were protected from feeding damage and showed significant reduction in adult emergence from infested plants by both susceptible and Cry3Bb1 and Cry34Ab1/Cry35Ab1-resistant WCR. These results demonstrate that proteins from B. laterosporus are as efficacious as the well-known Bacillus thuringiensis (Bt) insecticidal proteins in controlling major insect pests such as WCR. The deployment of transgenic maize expressing mMpp75Aa along with other active molecules lacking cross-resistance have the potential to be a useful tool for control of WCR populations resistant to current Bt traits.IMPORTANCE Insects feeding on roots of crops can damage the plant roots resulting in yield loss due to poor water and nutrient uptake and plant lodging. In maize the western corn rootworm (WCR) can cause severe damage to the roots resulting in significant economic loss for farmers. Genetically modified (GM) expressing Bacillus thuringiensis (Bt) insect control proteins, has provided a solution for control of these pests. In recent years populations of WCR resistant to the Bt proteins in commercial GM maize have emerged. There is a need to develop new insecticidal traits for the control of WCR populations resistant to current commercial traits. New proteins with commercial level efficacy on WCR from sources other than Bt are becoming more critical. The Mpp75Aa proteins, from B. laterosporus, when expressed in maize, are efficacious against the resistant populations of WCR and have the potential to provide solutions for control of resistant WCR.

Facile synthesis of silver nanoparticles using harmala alkaloids and their insecticidal and growth inhibitory activities against the khapra beetle

In order to find new, less toxic and eco-friendly pest control agents, natural products are considered to be alternative options of potentially active compounds. In this context, the aim of the present study was the isolation and structural elucidation of the β-carboline and quinazoline alkaloids of Peganum harmala L. seeds. Silver nanoparticles (AgNPs) were prepared using alkaloids through a green synthesis procedure. Harmala alkaloids and their AgNPs showed considerable insecticidal and growth inhibitory activities against khapra beetle, Trogoderma granarium (Everts) (Coleoptera: Dermestidae). On a toxicity bioassay using treated filter papers, the total harmala alkaloids (THAs) were the most toxic followed by harmaline, harmine and harmalol, where LC50’s ranged between (30.6–61.7 µg/cm2) and (24.4–46.1 µg/cm2) 24 h post-treatment against larvae and adults, respectively. The two quinazolines, vasicine and vasicinone, showed moderate to weak activities. At 48 h post-exposure, efficacy of all alkaloids was increased. When tested as AgNPs (size 22.5–66.2 nm diameter), toxicity of alkaloids, especially the β-carbolines, was strongly increased, where LC50 values ranged between (4.7–11.4 µg/cm2) and (4.1–10.2 µg/cm2) 48 h post-treatment against larvae and adults, respectively. Feeding the 2nd instar larvae AgNPs-treated grains at sublethal concentrations led to significant drawbacks on the normal growth and development of the insect. These effects appeared as a high percentage of malformed larvae and pupae, a prolonged life span and a significant reduction in adult emergence. Results suggest the potential of using harmala alkaloids and their AgNPs as a natural approach for controlling T. granarium.

BIOEFFICACY OF NEEM KERNEL AQUEOUS EXTRACT (NKAE) AGAINST TEA RED SPIDER MITE, OLIGONYCHUS COFFEAE, NIETNER AND ITS EFFECT ON STETHORUS GILVIFRONS MULSANT, A POTENTIAL PREDATOR OF RED SPIDER MITE

Neem kernel aqueous extract (NKAE) was evaluated at different concentrations (1-10%) against red spider mite, Oligonychus coffeae under laboratory and field conditions. Also the impact of NKAE on survival of Stethorus gilvifrons, a potential predator of red spider mite was studied. Parameters assessed were ovicidal and acaricidal activities, adult emergence, oviposition deterrent in case of red spider mite and larval & adult mortality and adult emergence for the predator. Significant ovicidal activity was exhibited at higher concentrations (6-10%). Nymphs were more susceptible to NKAE than adults. Higher concentrations (6-10%) showed 53-95% mortality of mite population under laboratory conditions. LC50 values of NKAE for nymph and adult red spider mite were found to be 47.73 mg/ml and 66.02mg/ml respectively after 24h of treatment. Field evaluation however exhibited 43-69% reduction of mite population at 6-10% concentrations. Egg laying by tea red spider mite on the NKAE treated tea leaf surface was significantly decreased (1.16-1.50 eggs/female/day) than control (3.83 eggs/female/day). Significant reduction in adult emergence (20.0-56.7%) and increased duration of total developmental period (1.00-4.33 days) were noticed at higher concentrations (4-10%) only. However, the application of NKAE on different life stages of S. gilvifrons showed no adverse effect in respect of their growth and development.

Pathogenicity of Beauveria bassiana isolated from Moroccan Argan forests soil against larvae of Ceratitis capitata (Diptera: Tephritidae) in laboratory conditions

The Mediterranean fruit fly, Ceratitis capitata Wiedemann (Diptera: Tephritidae), is the major tephritid pest in Morocco. This pest survives in Moroccan forests Argania spinosa and continually invades the nearest agricultural areas. Entomopathogenic fungi are an interesting tool for fruit fly control and hold a useful alternative to conventional insecticides. However, primary selection of effective pathogens should be taken in laboratory condition prior to applying them in the field. Here, we used third late instar larvae of C. capitata to investigate the effectiveness of 15 local Beauveria bassiana isolates. Results showed that all isolates were able to infect the larval stage, producing a large mortality rate in puparia ranging from 65 to 95 % and caused significant reduction in adult emergence. The fungal treatments revealed that the mycosis occurred also in adults escaping infection as pupariating larvae. The percentage of mycosed puparia was highest in strain TAM6.2 (95 %) followed by ERS4.16 (90 %), therefore they were the most virulent. Median lethal concentration (LC₅₀) was studied for five isolates at four concentrations ranging from 10⁵ to 10⁸ conidia ml⁻¹. The results showed that the slopes of regression lines for B. bassiana ERS4.16 (slope = 0.386) and TAM6.2 (slope = 0.41) were the most important and had the lowest LC₅₀ values (2.85 × 10³ and 3.16 × 10³ conidia ml⁻¹ respectively). This investigation suggests that the soil of Argan forests contains pathogenic B. bassiana isolates and highlights for the first time their potential as biological control toward C. capitata larval stage in Morocco.

Insecticidal potential of an endophytic fungus, Cladosporium uredinicola, against Spodoptera litura

The tobacco cutworm, Spodoptera litura (Lepidoptera: Noctuidae) (Fabricius), is a polyphagous pest which has developed physiological resistance against a number of known insecticides. In order to reduce the load of synthetic insecticides, ecofriendly alternative strategies are needed. The present studies were conducted to evaluate the insecticidal potential of the endophytic fungus Cladosporium uredinicola isolated from Tinospora cordifolia (Thunb.) on S. litura. Development of S. litura was significantly prolonged when larvae were fed on diet amended with ethyl acetate extract of C. uredinicola at concentrations of 1.25–2.00 μl g−1. The negative effects of fungal toxin on development of S. litura further resulted in a significant reduction in adult emergence, longevity and reproductive potential at higher concentrations. A significantly higher number of adults showed morphological deformities when larvae were fed on diet amended with 2.00 μl g−1 concentration. The inhibitory effects on growth and development of S. litura indicate toxicity of ethyl acetate extract of C. uredinicola, which is further evidenced by reduced food utilization by larvae. The antifeedant and toxic effects of ethyl acetate extract of C. uredinicola observed in the present studies can be attributed to a bioactive compound produced by the fungus, so this study provides evidence that C. uredinicola isolated from T. cordifolia possesses anti-insect properties and may play an important role in protecting plants against insect pests.

Laboratory Evaluation of Insecticidal Potentials of Kane Plant (Anogeissus leiocarpus Guil and Perr) for the Control of Bambara Groundnut Weevil (Callosobruchus subinnotatus Pic.) on Stored Bambara Groundnut ( Vigna subterranean (L.)Verdcourt)

Laboratory experiment was conducted during the year 2010 to evaluate the insecticidal potentials of different parts of Kane plant, Anogeissus leiocaipus Guil and Perri (leaves, stem and root barks), compare their efficacy with conventional insecticide (pirimiphos-methyl) and determine the concentration/rate that is effective in the control of damage caused by Bambara groundnut weevil, Callosobruchus subinnotatus Pic. on stored grains of Barn bar a ground nut (Vigna subterranae (L.) Verd.). The different parts of the plant materials were tested in powdered form at three different concentrations viz: 1, 3 and 5g/100g grain while the synthetic insecticide was applied at the recommended rate of 0.25g/100gseed. The experiment was laid out in a completely randomized design with each treatment replicated three times. The result shows that root bark at 1g/100g grain was the most effective in reducing oviposition (10.78) thereby bringing about a significant reduction in adult emergence (4.72), number of emergence holes (4.72), mortality (4.69) at 3 days after treatment (DAT) and grain damage (3 .07) while it competed favorably with the synthetic insecticide (pirimiphos-methyl). A significantly higher mortality of 2.89 and 2.89 in the first generation progeny was recorded in the leaf treated grains at 60 and 90 DAT, respectively. All the three different plant parts did not exhibit any significant negative effect on viability of the seeds tested. The stem bark and the leaves proved equal in efficacy to the root lark only at the highest rate/concentrations of 5g/100g grain. Based on the results of the experiments conducted, applications of the root bark of A. lelocarpus at the rate of 1- 5g/100g grain is recommended for an effective, cheap and safe protection of V. subterranean grains against damage caused by C. subinnotatus in storage.

Bioefficacy assessment of Melia azedarach (L.) seed extract on tea red spider mite, Oligonychus coffeae (Nietner) (Acari: Tetranychidae)

Aqueous seed extract of Melia azedarach (L.) was evaluated against tea red spider mite, Oligonychus coffeae (Nietner), in relation to mortality of adult mites, viability of eggs and subsequent adult emergence and oviposition deterrence in the laboratory, and the extract underwent field evaluation in terms of per cent reduction of the mite population. Direct spray methods were used in the laboratory with concentrations of 1%, 2%, 4%, 6%, 8% and 10%. Mortality of O. coffeae was dependent on both concentration and time (56.4% mortality on the first day; 95.6% mortality by the seventh day). The viability of eggs was reduced significantly compared with untreated mite's eggs. Significant reduction in adult emergence and increased duration of total developmental period were noted. Deposition of eggs by adult mites on treated leaf surface was decreased significantly compared with the control. No phytotoxic effect (score 0–5% and grade 1) was observed in the field when tea bushes were sprayed with different doses of aqueous seed extract of M. azedarach. The made tea samples were taint free. An organoleptic test scored both leaf infusions and liquor strength as good, scoring 6.5–7.0 on a 10-point scale. The availability and distribution of this plant (M. azedarach) in and around the tea-growing areas of the sub-Himalayan region, along with its processing for economic utility and inclusion in the current integrated pest management program, is discussed.

Effect of Catharanthus roseus (L.) (Apocyneaceae) extract on developmental stages of Erias favia stall

Developmental defect in Erias favia was investigated due to aqueous extract of Catharanthus roseus. The extract caused significant reduction in adult emergence as well as in percentage of egg hatch in Erias favia.

Laboratory evaluation of the insect growth regulator lufenuron againstHelicoverpa armigera on cotton

An insect growth regulator (IGR), lufenuron (Match 5EC), was tested for its toxicity toHelicoverpa armigera on cotton. Potency of the IGR against the larval stage of the pest was demonstrated with respect to larval instars; the LC90 values of 1st, 2nd, 3rd, 4th and 5th instar larvae were 5.63, 7.89, 8.03, 11.39 and 14.76 mg a.i.l −1, respectively. However, different larval instars did not differ significantly with respect to LC50 and LC10. IGR-treated larvae had swollen heads and were significantly smaller (1.5–2.3 mm) than the untreated control (2.9 mm). Larval weight was significantly reduced from 190 mg in the control to 50–70 mg in the lufenuron treatment. IGR treatment in the larval stage significantly affected both pupal length and pupal weight. Pupal duration of the test insect was significantly extended by IGR treatment. Pupal deformities, including an inability to shed the last larval skin and formation of larval-pupal intermediates, occurred following treatment. A significant reduction in adult emergence was recorded. In addition, abnormalities in the form of development of cavities in the forewings of adult were evident. A significant decline in fecundity was noted in the studies.

Mortality in Three African Tephritid Fruit Fly Puparia and Adults Caused by the Entomopathogenic Fungi, Metarhizium anisopliae and Beauveria bassiana

The pathogenicity of 13 isolates of Metarhizium anisopliae and two isolates of Beauveria bassiana to Ceratitis capitata and Ceratitis var. rosa fasciventris exposed as late third instar larvae in sand was evaluated in the laboratory. All isolates caused a significant reduction in adult emergence and a corresponding large mortality on puparia of both species. All isolates also induced large deferred mortality in emerging adults following treatment as late third instar larvae. On C. capitata , seven isolates ( M. anisopliae ICIPE 18, 20, 32, 60 and 69 and B. bassiana ICIPE 44 and 82) caused significantly higher mortality on puparia than other isolates. With the exception of ICIPE 32, the other four isolates of M. anisopliae above were the most pathogenic against C. r. fasciventris . Dose-response study carried out with these isolates of M. anisopliae on the two species of flies above plus another species, Ceratitis cosyra showed that the dose-mortality regression lines of ICIPE 18 and 20 were steeper with lower LC 50 values when compared with ICIPE 60 and 69 on the three species. When these two isolates were evaluated with regard to their pathogenicity to different pupal age, adult emergence was found to increase with increasing pupal age with a corresponding decrease in mortality in puparia and emerging adults in the three species of fruit flies. M. anisopliae ICIPE 18 and 20 were equally pathogenic to all pupal ages tested in C. capitata and C. cosyra but ICIPE 18 was more pathogenic to older puparia of C. r. fasciventris than ICIPE 20. Our results suggest that soil inoculation with M. anisopliae under mango trees might form an important component of integrated pest management strategies in areas where these three species of fruit fly coexist.

Effects of copper, nickel and zinc on the life cycle of the caddisfly Clistoronia magnifica (limnephilidae)

AbstractThe caddisfly Clistoronia magnifica (Banks) (Limnephilidae) was exposed to copper, nickel and zinc in life cycle tests. The copper test included continuous exposure of first‐generation aquatic larvae and pupae, second‐generation larvae and pupae and third‐generation larvae. The aerial adults and eggs were exposed only to body burdens obtained as larvae and pupae. Nickel and zinc tests included first and second‐generation exposure. Copper concentrations of ≥17 μg/L prevented completion of the life cycle, and significant reduction in adult emergence occurred at 13.0 μg/L. The no‐observed‐effect level for copper was 8.3 μg/L. Nickel concentrations of ≥250 μg/L prevented completion of the life cycle. The no‐observed‐effect level for nickel was 66 μg/L. At the highest zinc concentration (5,243 μg/L), no effects were observed on any of the life stages.