Cowpea Weevil Research Articles

Bioinsecticidal efficacy of Eucalyptus camaldulensis (Dehn) and Hyptis suaveolens (L.) Poit. leaf extracts on Callosobruchus maculatus (Cowpea weevil)

The modern method of controlling insect pests, using synthetic insecticides has caused serious problems to human health and the environment. Hence, the need for alternative, cheap, readily available and acceptable insect pest control methods, among which are the use of plant leaf extracts. The aim of this study was to determine the bioinsecticidal efficacy of Eucalyptus camaldulensis and Hyptis suaveolens against cowpea weevils (Callosobruchus maculatus). The bioassay of the powdered methanol extracts of leaves of E. camaldulensis and H. suaveolens was carried varying quantities (3 g, 6 g, 9 g and 12 g) of powdered extracts of the respective plant samples were mixed separately with 50 g of cowpea. Synthetic insecticide, Al2(PO4)3 was used as positive control while the negative control contained no treatment. Proximate compositions of the treated and untreated cowpeas were done using standard procedures while the extracts were characterized using Gas Chromatography-Mass Spectroscopic. Although mortality rates of the C. maculatus in presence of the extracts did not follow any dose-dependant trend, the respective dosages used for treatments inhibited the growth and activities of Callosobruchus maculatus. A high rate of seed damage was observed in the untreated cowpea seeds. Gas Chromatography-Mass Spectroscopy of the extracts identified the presence of seven potential insecticidal compounds (Bargamotene, Globulol, Humulene, Linolein, Prasterone, Terpinen-4-ol and Traumatic acid) in Hyptis suaveolen. In the Eucalyptus camaldulensis extract, 13 potential insecticidal compounds (Barosma camphor, Carvacrol, Carbazon, Irone, Isoborneol, 5-methyl, 1,4-Naphthoquinone, Oleic Acid, Phytol, Piperitone, Pyrazole-3-carboxylic acid, Terpinen-4-ol, Viridiflorol) were identified. The bioinsecticidal activities of these plant extracts could be attributed to the presence of phytochemicals and isolated insecticidal compounds.

CHEMICAL COMPOSITION OF VOLATILE COMPONENTS PULICARIA SALVIIFOLIA AND P. GNAPHALODES AND THEIR INSECTICIDAL ACTIVITY

Pulicaria salviifolia and P. gnaphalodes belong to one of the richest terpenoid plants of the genus Pulicaria (family Asteraceae). The genus includes 63 species, 16 species grow in Uzbekistan. In folk medicine, plants are actively used to treat various diseases, and have long been used as a natural remedy for mosquitoes, flies and fleas. Secondary plant metabolites are of great practical interest as a natural raw material for the creation of biopesticides.
 The aim of this work was to study the chemical composition of the volatile components of gasoline fractions of Pulicaria salviifolia and P. gnaphalodes plants and to study their insecticidal activity against the number of insect pests.
 For the first time, the composition of volatiles in the aerial parts of Pulicaria salviifolia and P. gnaphalodes was studied by GC/MS. It was revealed that the predominant components of P. salviifolia are β-terpineol (10.44%), isospatulenol (8.00%), iceol (6.79%), sabinene hydrate (5.72%), l-caryophyllene (4.24%), terpinene-4-ol (4.07%), d-cadinene (3.65%), α-amorphous (2.30%). Calaminene (12.44%), 2-phenylpyrazol-3-amine (8.61%), 1,3,5-cycloheptatriene (7.71%), 1,8-cineole (6.06%), 2-heptene dominate among the volatile substances of P. gnaphalodes-1-ol, 2-methyl-6-(4-methylphenyl)-, (E)- (6.04%), 1-bromohomoadamantane (5.73%), 7-acetyl-2-hydroxy-2-methyl-5-isopropylbicyclo[4.3.0]nonane (4.83%). Gasoline fractions of Pulicaria salviifolia and P. gnaphalodes were tested for insecticidal activity against apple aphid (Aphis pomi), peach aphid (Myzus persicae Sulzer) and cowpea weevils (Callosobruchus maculatus). An insecticidal activity was studied in laboratory conditions. A comparative study of the biological activity of the fractions showed that the biological efficiency of the P. gnaphalodes extract fraction after 24 hours at 0.5% concentration was higher: in relation to Aphis pomi 96.6%, Myzus persicae Sulzer – 76.0% and Callosobruchus maculatus – 90.0%, for the fraction of Pulicaria salviifolia extract in a 0.5% dose, these indicators were 60.2%, 72.0% and 86.6%, respectively.

Effects of Excess Insecticide Application on Cowpea (Vigna unguiculata) Seeds by responses of Colonized Cowpea Weevil (Callosobruchus maculatus)

This study was designed to determine the effect of excess insecticide application on stored cowpea (Vigna unguiculata) seeds sourced from Lapai market, Niger State, Nigeria using appropriate standard techniques. The effect quantum was using cowpea weevil (Callosobruchus maculatus) as Biomarker. Result obtained show that lethal concentration of insecticide significantly (P < 0.05) affected duration of immature development, with highest concentration increasing the duration of larval development significantly. Larval and pupal mortality (11.20±1.24 and 67.20±4.65; 8.04±0.44 and 36.20±2.11 for negative control and highest treated concentration respectively) were significantly (P < 0.05) affected by increase in insecticide concentration. Mean temperature and relative humidity (28.77±1.2 and 35.88±5.14 respectively) of the immediate stored cowpea environment were within the ambient condition. Protein and Carbohydrate were the two proximate composition that varied significantly as a result of insecticide application. Cowpea weevil have shown a great potential of serving as a potential bio-markers of insecticide contamination of stored cowpea seeds in storage. Further research on similar and other biological effects of abused insecticide on colonizing weevil should be carried out in and outside laboratory condition.

Efficacy of Plant Derivatives in Protecting Mungbean Grains against Cowpea Weevil (Callosobruchus maculatus) under Storage Conditions in Southern Bhutan

Food grains infestation by insect pests in stores is a severe challenge in food production around the globe, especially in wet and humid regions. In Bhutan, mung bean is commonly grown for consumption as a superior source of protein. However, severe cowpea weevil infestation is observed while in storage condition. Controlling with synthetic pesticides is associated with health risks due to toxic residues which intervene in safe and healthy protection methods. Protecting the grains in-store through organic approach is imperative for consumption and seed purposes. Some botanical plant extracts are known for their protective properties which need location-specific studies based on availability and suitability. Therefore, this study was conducted to evaluate the efficacy of eight treatments (Acorus calamus rhizome powder, mustard oil, garlic cloves, turmeric rhizome powder, wood ash, Vitex negundo leaf powder, super grain bag including untreated control) against cowpea weevil (Callosobruchus maculatus) in mungbean under storage condition. The experiment was laid in a randomized complete block design with three replications. The result revealed that the lowest mean number of grains perforated and percent grain perforated were recorded in grains treated with Acorus calamus rhizome powder (0.46 & 0.20 %) followed by mustard oil (1.05 & 0.47 %) and grains stored in super grain bag (5.74 & 2.49%), which were significantly lower (P<0.001) as compared to other treatments. The lowest number of adult cowpea weevils was also recorded in grains treated with Acorus calamus and mustard oil followed by grains stored in super grain bag. Germination percentage was found highest in wood ash followed by mustard oil, Acorus calamus and garlic-treated grains while the lowest was in super grain bag. Therefore, Acorus calamus rhizome powder and mustard oil were found to be effective in managing cowpea weevil without affecting seed germination and vigour.

EFFECT OF MORINGA (MORINGA OLEIFERA) LEAF POWDER, NEEM (AZADIRACHTA INDICA) LEAF POWDER, AND CAMPHOR ON WEEVIL (CALLOSOBRUCHUS MACULATUS F.) IN STORED COWPEA (VIGNA UNGUICULATA (L.) WALP) SEEDS

Cowpea (Vigna unguiculata (L.) Walp.), one of the most important leguminous crops, is widely cultivated throughout the tropics, especially in the savanna regions of the world. However, its seed is attacked by several insect pests both in the field and in storage, especially the cowpea weevil. To control weevils, most farmers have adopted the use of chemical insecticides, but these insecticides come with health and environmental problems, and as a result, there is advocacy for the use of bio-pesticides in the form of tree botanicals. This study was conducted to assess the effects of neem leaf powder (NLP), moringa leaf powder (MLP), and camphor against the cowpea weevils (Callosobruchus maculatus) in a completely randomized design. Six treatments were used and allocated as T1 (control), T2 (4g of camphor), T3 (25g of NLP only), T4 (25g of MLP only) T5 (50g of NLP only) and T6 (50g of MLP). The treatments were replicated three times. The parameters studied were the numbers of damaged and undamaged seeds, the numbers of dead and live weevils, and the taste of cowpea seeds. The treatments effectively protected the cowpea seeds during the storage period of eight weeks. The preservation of cowpea seeds given by camphor was significantly different from the other treatments. However, there was no significant difference (p >0.05) between the neem and moringa leaf powders treatments. The use of moringa and neem leaf powders might be adopted by cowpea farmers in sub-Saharan Africa as alternative, cheap, and available sources of biopesticides to use as chemical insecticides. If cowpea seeds are to be stored for consumption purposes, moringa leaf powder should be used since most respondents preferred the taste of cowpea seeds treated with moringa. Additionally, the storage duration of eight weeks was too short for the experiment, so further studies can be carried out for an extended period of more than eight weeks.

Genetic diversity and structure of Callosobruchus maculatus populations in the different agro-ecological zones of Senegal

The objective of this study is to determine the diversity and genetic structure of cowpea weevil populations in the different agro-ecological zones of Senegal. Thus, to achieve this objective, individuals of Callosobruchus maculatus from localities in each zone were used, after sampling and massive breeding. The sequenced gene is Cyt-B. The results showed high haplotypic diversity (0.901 ±0.00033) and low nucleotide diversity (0.010 ±0.0000003). These diversities studied by agro-ecological zone show that the Casamance zone has the greatest haplotypic diversity (0.901; P>0.05) while the eastern Senegal zone has the lowest value (0.439; P>0.05). The nucleotide diversity is lower in the Sylvo-pastoral zone (0.00112; P<0.05) and higher in the Casamance zone (0.01052; P<0.05). The genetic structuring shows that the Senegal River Valley-eastern Senegal zone couple is more differentiated [FST(Fixation index)]=0.70687; P<0.05) and the Casamance-Groundnut Basin zone couple is less differentiated (FST=0.21248; P<0.05). The greatest genetic distance was found between the Sylvo-pastoral zone and the River Valley and the smallest between the eastern Senegal zone and the River Valley. However, a significant genetic variation within the populations was noted (64.93%). Overall we have a low level of diversity and weakly structured populations except those of Tamba and Fouta. A slight influence of the zones was also noted.

Evaluation Efficacy Of Some Oils Plant Against Of Callosobruchus maculatus (Fabricius) (Coleoptera: Bruchidae)

This study was conducted to know the impact of treatment of cowpea seeds plant oils as following: - Black seed, castor, sunflower, Alsi and Brassica on Southern cowpea weevil C. maculatus at concentration of (1.5, 3, 4.5) ml / kg seeds.
 The study showed superiority of mustard oil in reducing the average of number of eggs laid on the seeds as it reached 161.13 while the highest rate reached to 208.25 when the testing seeds treatment with sunflower oil. The study also showed that the longer period for exit of the members of the first generation (F1) 28.08 day when the seed treated with mustard oil, while minimum period of 27.00 days when treated with castor oil seeds. We see that the lowest rate for a number of emerging insects 48.50 at the treatment of linseed oil, while the highest rate for a number of emerging insects 53.50 at the treatment of black seed oil. It was found that the lowest rate of damage was 24.90% with linseed seed oil and the highest rate was 29.73 with black seed oil, While the highest rate was in seed weight 21.60% with black seed oil and the lowest rate was 16.88% with mustard oil, And the treatment of the seeds of cowpea plant oils which was used in this study did not show adverse effects on the vital seed treatment significantly. As the results showed that the amount of oil is inversely proportional to both the number of eggs and emerging insects and the percentage of damage, loss and germination, and directly proportional to the period of time required for the exit of members of the first generation (F1).

Root elongation test on seeds of Sinapis alba reveals toxicity of extracts from thirteen colour forms of the Asian multi‐coloured ladybird, Harmonia axyridis

AbstractLadybirds (Coleoptera: Coccinellidae) use toxic compounds such as alkaloids in their hemolymph to defend against predators and pathogens. Direct measurement of their toxicity to predators is unavailable as predators show various avoidance reactions without eating the beetles. Because inhibition by harmonine – the alkaloid of the alien invasive ladybird Harmonia axyridis (Pallas) – was observed in many organisms, its toxicity can also be tested on various non‐target organisms. This is the first study examining ladybird alkaloid toxicity to plants. We used a quick, inexpensive, and easy‐to‐perform method to quantify the phytotoxicity of 13 strains of H. axyridis, representing natural colour forms and spontaneous laboratory mutations. We used the seed germination rate and root elongation of seedlings of Sinapis alba L. (Brassicaceae). Following a logistic curve, root length decreased with increasing concentration of the extract from adult beetles. The effect of extracts from the cowpea weevil, Callosobruchus maculatus (Fabricius) (Coleoptera: Chrysomelidae) (negative control) did not differ from the control (water). Extract from the lesser mealworm Alphitobius diaperinus (Panzer) (Coleoptera: Tenebrionidae) (positive control) decreased the root length to about half of that of the negative control. Extract from young ladybirds (1 week old) decreased the root length to about one‐third of the control and the extract from 3‐month‐old ladybirds to one‐10th. Differences in toxicity among all 13 strains were minor and not consistent for the two age cohorts.

Critical components and loss factors in inoculated and non-inoculated cowpea varieties grown in the Brazilian Amazon

The cowpea (Vigna unguiculata [L.] Walp) is of social and economic importance in developing countries. There are several factors that lead to low cowpea yields in tropical regions, such as pests and low technological development. This study aimed to identify and quantify losses in the critical component of production, and the key loss factors for three cowpea varieties (buttermilk, milk, and vinegar) grown in Santarém, Brazil, and inoculated or not with Bradyrhizobium japonicum. Crop life tables, loss factors, and production components of the three varieties were evaluated. Differences in yield and total losses were observed between varieties, but not between treatments with and without inoculant. In all three varieties, flowers were a critical component of production, and flower abortion was the key factor behind losses. Grain losses contributed significantly to total losses. The factors that contributed the most to grain component losses in all three varieties were malformation of grains and non-fertilisation of eggs. Inoculation increased losses through increased abortion of flowers in the buttermilk and milk varieties. Inoculation also increased damage caused to cowpea plants by cowpea weevils, Callosobruchus maculatus, in the buttermilk variety. Inoculation increased the total losses in the three varieties studied.

Sustainable Strategies to Counteract Mycotoxins Contamination and Cowpea Weevil in Chickpea Seeds during Post-Harvest.

Mycotoxins contamination and pest infestation of foods and feeds represent a pivotal threat for food safety and security worldwide, with crucial implications for human and animal health. Controlled atmosphere could be a sustainable strategy to reduce mycotoxins content and counteract the vitality of deleterious organisms in foodstuff. Ozone treatment (O3, 500 ppb for 30, 60 or 90 min) and high nitrogen concentration (N2, 99% for 21 consecutive days) were tested in the post-harvest management of four batches of Cicer arietinum grains to control the presence of mycotoxigenic fungi and their secondary metabolites, as well as pest (i.e., Callosobruchus maculatus) infestation. At the end of the treatment, O3 significantly decreased the incidence of Penicillium spp. (by an average of -50%, independently to the time of exposure) and reduced the patulin and aflatoxins content after 30 min (-85 and -100%, respectively). High N2 concentrations remarkably reduced mycotoxins contamination (by an average of -94%) and induced pest mortality (at 100% after 5 days of exposure). These results confirm the promising potential of O3 and N2 in post-harvest conservation strategies, leading to further investigations to evaluate the effects on the qualitative characteristics of grains.

Atmospheric Cold Plasma (ACP) Treatment for Efficient Disinfestation of the Cowpea Weevil, Callosobruchus maculatus

Highlights The exposure of C. maculatus to reactive gas species (RGS) from atmospheric cold plasma treatment (ACP) resulted in significant mortality at all life stages tested. Three-minute ACP treatments at voltages of 70 kV have the best insecticidal effect. The greatest impact of treatment was during the egg and young larval stages of C. maculatus. Abstract. The insecticidal capability and mechanism of high-voltage atmospheric cold plasma were studied using a dielectric barrier discharge reactor against Callosobruchus maculatus, a significant insect pest in stored grain degradation. The mortality rate of > 90.0% for egg and larval stages can be achieved with a longer treatment time of 3 minutes and a higher voltage of 70 kV. However, this treatment condition, paired with a post-treatment retention time of 4 days, is required to kill 95% of adult insects. The use of atmospheric cold plasma has a considerable impact on the mortality of a range of insect life stages. Sufficient toxicity can be achieved by plasma process management using modified atmospheric pressure with a working gas of 65% oxygen, 30% carbon dioxide, and 5% nitrogen to address the insect lifecycle phases that are vectors for pathogens, which can increase mycotoxin contamination and degrade grain quality. Introducing atmospheric cold plasma treatment as an alternative to chemical fumigation may provide a safer alternative for integrated pest management. Keywords: Atmospheric cold plasma (ACP), Cowpea weevil, Dielectric barrier, Insecticidal effect, Integrated pest management (IPM), Pesticide, Reactive gas species (RGS).

Chemical Composition of Different Extracts of <i>Conyza bonariensis</i>: Insecticidal and Nematicidal Activities

C. bonariensis (L.) Cronq. known as hairy fleabane was first described in Argentina but it is now widely spread through most warmer regions of Europe, Africa, Asia, the Caribbean and Central America. In this work, a chemical analysis by liquid and gas chromatography coupled with mass spectrometry of the whole plant, aerial part, flowers and roots extracts of C. bonariensis harvested in Togo (West Africa) was carried out. Two acetylenic compounds Lachnophyllum ester and limonene were identified as the main components of essential oils while Lachnophyllum and Matricaria lactones were dominant in chloroform extracts. Based on the plant chemical compositions, essential oils and chloroform extracts were tested on cowpea weevil Callosobruchus maculatus adults which are considered as one of the most cosmopolitan pests of stored beans, and on freshly hatched second-stage juveniles of root-knot nematode Meloidogyne incognita. Results showed that the whole plant essential oil demonstrated an LC50/24h value of 1.75 μL oil/L air on C. maculatus while at 3.91 μL oil/L air, it showed 100% mortality. Furthermore, the plant root chloroform extracts partitioned in diethyl ether-hexane mixture showed the strongest nematicidal activity with an LC50/72h value of 0.47 mg/mL. Our findings suggest that the widely diffused plant C. bonariensis and its acetylenic constituents could be considered as potent botanical insecticidal and nematicidal agents.

Insecticidal Potentials of Capsicum chinense (Jacq) and Garcinia kola (Heckel) Extracts on Callosobruchus maculatus (Cowpea Weevil) Infestation

The use of synthetic organic pesticides has resulted in significant environmental pollution that threatens human health and kills unintended organisms, leading to their eventual restriction and a demand for better alternatives. In this study, the insecticidal potentials of ethanolic extracts of Capsicum chinense and Garcinia kola against Callosobruchus maculatus infestation on cowpea were assessed. From the results, it can be concluded that exposure time and extract concentration increased mortality. The data obtained demonstrated a significant change (p<0.05) in 2 g at 24 hours and 48 hours following exposure. The concentration and time-dependent mortality of C. maculatus in C. chinense extract increased. Mortality was observed 100 % at 4 hours in 2-8 g of the extract when compared to the control. Values ranged from 3.600.55 to 10.000.00 for the effect of the C. chinense extract at 2 g, and there was no discernible difference (p>0.05). The results were considerably different (p<0.05) at 4 g and 6 g compared to the control. The toxicity rate of the plant extracts on the test organism was also seen to increase from day 1 to day 3. The insects moved jerkily and quickly and tended to try to get out of the Petri dishes. The plants' strong insecticidal and repellent properties suggest that they are useful for managing and controlling the cowpea weevil and can be used as an alternative to commercially available harmful insecticides.

Species of Mung Bean Main Pests of Second Sowing Date, Their Distribution

An overview of the species of the main pests of mung bean (Vigna radiata (L.) R. Wilczek) is given. The research was carried out in 2017-2019 in the fields of farms in the Tashkent region. Systematic analysis of species was carried out according to standard methods. Dispersion analysis of the obtained results was determined by the method of B. A. Dospekhov. 26 species of pests and 10 species of natural entomophages were identified, of which 5 species are the main ones (spider mites, turnip moth, cotton bollworm, alfalfa plant bug, southern cowpea weevil). The least damage to the culture is caused by 3 species of weevils: southern cowpea weevil (Callosobruchus maculatus (Fabricius, 1775)), pea weevil (Bruchus pisorum Linnaeus, 1758) and American seed beetle (Acanthoscelides obtectus (Say, 1831)). These pests infect mung bean culture up to 47.7-53.2%. The spider mite infects second sowing date mung bean twice as much as the main crop. The damage to the main crop amounted to 25.2-28.1%, and with the second sowing date — 48.1-49.7%. Based on the conducted research, it was concluded that the development of environmentally friendly, environmentally friendly methods of combating the main pests of mung bean in accordance with modern technologies is one of the most important tasks today.

Evaluation of Insecticidal Potentials of Five Plant Extracts against the Stored Grain Pest, Callosobruchus maculatus (Coleoptera: Bruchidae).

Plant based insecticides are considered among the most economic and ecofriendly chemicals for the protection of plants and stored grains. The cowpea weevil (Callosbruchus maculatus) causes more than 90% damage to sored grains in three to six months. The current study investigates insecticidal potentials of five selected botanicals: Melia azedarach, Nicotiana rustica, Azadirachta indica, Nicotiana tabacum and Thuja orientalis. They are explored at six different concentrations (0.5, 1.0, 1.5, 2.0, 2.5 and 3.0%) against C. maculatus and compared to effects of distilled water which is used as a control. Toxicities of 3%(V/V) extracts of N. tabacum, N. rustica, A. indica and T. orientalis against C. maculatus were 100%, 86.11%, 80.56% and 72.22%, respectively. Maximum mortality was caused by N. tabacum and N. rustica (100%), followed by A. indica (82%), whereas minimum mortality was observed in T. orientalis (64%) at 2.5%. Several phytochemicals, alkaloids, saponins, diterphenes, phytosterol, flavonoids and phenols were identified in N. tabacum and N. rustica, while few were present in A. indica. Phytosterol was present in greatest abundance. Saponins were only detected in aqueous extracts of N. rustica and N. tabacum. Taken together, these results indicate the utility of N. tabacum, N. rustica and A. indica as potential botanicals to control pest beetle and cowpea weevil.

Chemical Composition and Evaluation of Antifungal and Insecticidal Activities of Essential Oils Extracted from Jambosa caryophyllus (Thunb.) Nied: Clove Buds.

Jambosa caryophyllus has been used in traditional phytotherapy as a treatment against infections. In the present work, essential oils extracted from clove buds (Jambosa caryophyllus ) (EO-JC) were investigated for their composition, antifungal, and insecticidal properties. Extraction of EO-JC was performed by use of hydrodistillation using a Clevenger-type apparatus, and the EOs were analyzed by gas chromatography coupled with mass spectrometry (GC-MS). Antifungal activity of EO-JC was evaluated by the use of solid-state diffusion (disc method) and microdilution to determine the minimum inhibitory concentration (MIC), against three strains of fungus, Aspergillus niger, Aspergillus flavus, and Fusarium oxysporum. Insecticidal activity of EO-JC against the cowpea weevil, Callosobruchus maculatus, was determined to assess utility of EO-JC to control this pest. Several exposures including inhalation and contact were used to determine lethality, as well as the repulsion test was conducted at concentrations of 4, 8, 16, and 32 μL EO-JC. Characterization of EO-JC by GC/MS revealed 34 compounds accounting for 99.98% of the mass of the extract. The predominant compound was eugenol (26.80%) followed by β-caryophyllene (16.03%) and eugenyl acetate (5.83%). The antifungal activity of EO-JC on solid media exhibited inhibitions in the range of 49% to 87%, and MIC was between 3.125 and 7.80 μg EO-JC/mL. Insecticidal activity, as determined by the use of the inhalation test, and expressed as the LD50 and LD95 after 96 hours of exposure was 2.32 and 21.92 μL/L air, respectively. In the contact test, a 96-hour exposure resulted in LD50 and LD95 of 5.51 and 11.05 μL/L of air, respectively. EO-JC exhibited insecticidal activity against fungi and pest chickpea weevil.

The Efficacy of Methyl Alcohol Extracts of Albizzia lebbeck (L.) Benth Seeds , Melia azedarach L. Fruits and their mixture in Comparisom with Actellic Insecticide on Eggs and adult emergence of cowpea weevil Callosobruchus maculatus (Fab.)(Coleoptera:Bruc

This study has carried out in laboratory to reveal the efficacy of methyl alcohol extract of Albizzia lebbeck (L.) Benth seeds and Melia azedarach L. fruits , in addition to their mixtures ( 1:1) , which is compared with the insecticide Actellic 50% EC., on Eggs and adult emergence of cowpea weevil , Callosobruchus maculatus (Fab.) under laboratory conditions of 30+ 2 C. and 60+5% relative humidity.Results have shown that there is significant differences in percentages of egg hatching of 1 , 2 and 3 days old which is treated with concentrations of 2,4,6,8,10% of methyl alcohol extract of Albizzia lebbeck seeds and Melia azedarach fruits ; the concentrations of 1,2 and 3% of the mixture of both and the concentrations of 0.05 , 0.075 % of the insecticide. There is a converse relationship between egg hatching and concentrations . Eggs of 1 day old are more resistant than other ages , since the highest egg hatching , 87.5% and 72.2% for Albizzia lebbeck seeds and Melia azedarach fruits respectively occur with 2% concentration compared with control which is 98.00 and 96.00% for both of them respectively. While Adult emergence has reached 80.36 and 75.6 % compared with control which is 94.00 and 100.00% for both of them respectively for the same age and concentration. The lowest hatching and emergence percentages are 52.5 and 69.79% of Albizzia lebbeck seeds extract at 6% concentration and 17.5 , 72.22 % of Melia azedarach fruits extracts at 8% concentration . No egg hatching occurs at 8% concentration of Albizzia lebbeck and 10% of Melia azedarach extracts for all ages .The highest egg hatching of 1day eggs old and adult emergence is 45.49 and 87.50 % at 1% concentration for mixed extraction compared with control which is 100.0 and 96.67 % . The lowest egg hatching is 5.00 % at 3% concentration and the lowest adult emergence 25.0% at 2% concentration compared with control which is 100.0 and 93.33% for eggs of 3 days old ; and there is no adult emerged at 3% for all ages . The highest egg hatching of 55% occurs at 0.05 concentration of actellic for 1 day old compared with control treatment which is 100.0% , and there is no hatching for the other ages and concentrations.

Synergistic effect of Balanites aegyptiaca essential oil and storage materials on cowpea seeds

The cowpea (Vigna unguiculata L.) is a legume produced and consumed all over Africa and especially in Nigeria. These beans are a major source of protein in the region. The cowpea weevil (Callosobruchus maculatus L.) is a major pest that affects cowpea seeds. Therefore, cowpea farmers need effective non-toxic pesticides to replace synthetic chemicals. The present research tested the effect of Balanites aegyptiaca L. essential oil on cowpea weevils.
 This research quantified weevil proliferation and cowpea seed qualities. The samples were treated with 5, 10, and 15 mL of B. aegyptiaca essential oil diluted in 1 mL of acetone and stored in five storage materials, i.e., jute bags, polythene bags, sacks, plastic containers, and glass bottles. The study featured a completely randomized design with three replications of each treatment: treatment time – 90 days, storage temperature – 30 ± 5°C, check – 0.125 g of aluminum phosphide, control – acetone.
 B. aegyptiaca essential oil proved to be an effective insecticide against cowpea weevils. The treatment achieved 100% mortality rate at 10 and 15 mL of B. aegyptiaca essential oil after 72 h of exposure in glass bottles, plastic containers, and jute bags. In addition, B. aegyptiaca essential oil demonstrated a potent activity against oviposition and survival of immature cowpea weevils. Cowpea seeds packaged in glass bottles, plastics containers, and jute bags showed significantly less damage than those stored in sacks and polythene bags. Glass bottles were the best storage material in terms of safety and shelf stability, followed by plastic containers and jute bags. 
 B. aegeptica essential oil has potent insecticidal properties and can be used as pest control during grain storage.

Evaluation of resistance of six chickpea cultivars to the cowpea weevil, Callosobruchus maculatus (F.) (Coleoptera: Chrysomelidae: Bruchinae) with age-stage, two-sex life table

The cowpea weevil, Callosobruchus maculatus (F.), is an important insect of stored grains with a worldwide distribution. The effect of six chickpea cultivars namely Adel, Azad, Azkan, Hashem, Goksu, and Mansour on the life history, population growth, and reproduction parameters of C. maculatus was investigated in the laboratory at 30 ± 2 oC, 60 ± 5% RH and 12L:12D, using the age-stage, two-sex life table method. The cowpea weevils fed on Azkan, Azad, and Goksu cultivars have a longer total development period, whereas those fed on Adel cultivar, have shorter ones. The longer longevity occurs in the insects fed on Goksu, Azad, and Adel cultivars, respectively, whereas, shorter ones in Hashem cultivar. The cowpea weevil females fed on Azkan and Hashem cultivars have higher and lower fecundity, respectively. The intrinsic rate of natural increase (r) shows a more increase in the cowpea weevil populations in Adel than Azad cultivar. The highest and lowest age-specific fertilities occur in Azkan and Hashem, respectively. The C. maculatus female weight decreases and increases with feeding on the cultivars Azad and Adel, respectively. Based on our findings, Adel is a moderately susceptible and Azad and Hashem are resistant hosts for feeding C. maculatus. So, resistant cultivars may be a safe and clean method for stored crop preservation and storage pest control.

Oviposition preference, population growth and digestive enzymatic function of Callosobruchus maculatus (F.) (Coleoptera: Chrysomelidae) on six legume grains

The cowpea weevil, Callosobruchus maculatus (F.) (Coleoptera: Chrysomelidae) is one of the most pernicious pests of stored legume grains in tropical and subtropical areas. Population performance and digestive enzymatic function of C. maculatus can be affected by nutritional quality and antinutritional compounds of legume grains on which it was fed. We reared C. maculatus on six legume grains (cowpea, chickpea, mung bean, soybean, faba bean, and peanut) to investigate the effects of the insect feeding on free-choice oviposition preference, population growth and digestive enzyme activity. The laboratory experiments were conducted at 28 ± 1 °C, relative humidity of 65 ± 5% and 24 h darkness. In a free-choice situation with other legume grains present, females laid the highest number of eggs on cowpea, and avoided laying eggs on peanut. Pre-adult survival of the weevil was the lowest on peanut and highest on mung bean. The developmental period on soybean and faba bean was longer than on mung bean and cowpea. Fecundity (number of eggs laid per female) of C. maculatus on cowpea grains was about 3.7-fold more than on peanut. The intrinsic rate of increase (r) and finite rate of increase (λ) on cowpea, mung bean and chickpea were higher than on soybean, faba bean and peanut. Amylolytic activity of fourth instar larvae fed with peanut, soybean and cowpea was higher than faba bean. Total proteolytic activity of these larvae fed with cowpea was higher than chickpea and mung bean. Our results indicate that cowpea, mung bean and chickpea are the most vulnerable hosts to C. maculatus infestation. The grain coat thickness and phenolic content of tested legumes play an important role in the development and population growth of C. maculatus, and these features could be used to develop effective management of this pest by the production of genetically engineered cultivars.