Application Of Synthetic Pesticides Research Articles

Biorationals and Synthetic Insecticides for Controlling Fall Armyworm and Their Influence on the Abundance and Diversity of Parasitoids

Spodoptera frugiperda (fall armyworm, FAW) is a significant economic pest of maize in Uganda. Many Ugandan maize farmers employ synthetic insecticides as their main form of control despite the negative impacts of these chemicals. We tested the effectiveness of Beauveria bassiana; General Biopesticide Cocktail (mixture of B. bassiana, M. anisopliae, Isaria fumosoroseus, Lecanicillium lecani and Purporeocillium lilacanus three strains of Metarhizium anisopliae, Nimbecidine® (azadirachtin 0.03%EC), and Roket® (cypermethrin 4% and profenofos 40%); and Amdocs® (emamectin benzoate 2% and abamectin 1%) on fall armyworm and parasitoids, respectively, in 2020 and 2021. The treatments with the greatest decrease in leaf damage and infestation were Amdocs® and Roket®, followed by Nimbecidine®. The biopesticides were not always more effective than the untreated control, though; their efficacy was often lower than that of the synthetic and botanical pesticides. We recovered one egg parasitoid, Telenomus remus, and seven egg and egg-larval parasitoids (Coccygidium luteum, Coccygidium sp., Cotesia icipe, Chelonus sp., Micranisa sp., Charops cf. diversipes, and an unidentified Tachinidae). Among these, C. cf diversipes, Chelonus sp., C. luteum, C. icipe and the Tachinidae were the most abundant. Parasitism was low, averaging 10% for egg masses and 5.3% for larvae. Application of synthetic pesticides and Nimbecidine® often resulted in higher yield when compared with the untreated control. In general, a low population of parasitoids was observed. Although the parasitoid population reduced in plots treated with Amdocs® and Roket®, the percentage of parasitism of FAW was not affected. In some instances, higher yields were realized in untreated control when compared with the treated plots. Pest management practices more compatible with biological control need to be considered for the management of fall armyworm.

The effectiveness of garlic extract against Spodoptera litura on Chili

Spodoptera litura is a polyphagous pest and attack many families of cultivated plants, such as chili plants. Application of synthetic pesticides is still the mainstay for controlling this pest in the field. To support eco-friendly plant protection management, it is important to explore potential natural materials such as garlic extract. This research aims to determine the potential of garlic extract in controlling S. litura on chili plants, and to see its indirect effect on chili yield. The research was carried out in two sites, in the laboratory and the field. The experiment used a completely randomized design with 6 treatments and 4 replications. The concentrations of garlic extract, i.e., control (0%), 24%, 26%, 28%, 30%, and 32%. The results showed the application of garlic extract had a significant effect on the mortality of S. litura, the frequency of attacks, and the intensity of pest attacks in the field, and had an effect on the variable number of fruit and fruit weight of chili plants. The LC50 and LC90 values reached 19.66% and 29.97% in the laboratory, and 28.30% and 34.3%% in the field, respectively. The LT50 and LT90 values from the 32% garlic extract in the laboratory were respectively 3.37 and 7.23 days. The application of garlic extraction affected growth and yield, i.e. healthy leaves, number of fruits, and weight of fruits in chili. The garlic extract is potentially used as an organic pesticide to suppress the S.litura attacks while keeping the plant's growth and yield.

Efficacy of Entomopathogenic Fungi as Prevention against Early Life Stages of the Red Palm Weevil, Rhynchophorus ferrugineus (Coleoptera: Curculionidae) in Laboratory and Greenhouse Trials.

The red palm weevil (RPW) Rhynchophorus ferrugineus is a highly destructive invasive pest for palms whose management is mainly by application of synthetic pesticides. As a key pest of date palm plantations, it is necessary to integrate environmentally safe measures for its management. Entomopathogenic fungi (EPF) have been primarily studied as a preventative control measure due to the horizontal transfer of conidia within the RPW population. We previously demonstrated the horizontal transmission of fungal conidia from an egg-laying surface to the female weevil and then to the eggs and larvae. Based on that strategy, this study aimed to evaluate the virulence of commercial EPF products and laboratory EPF preparations to RPW females and their progeny, and their ability to protect palms against infestation. As such, it serves as a screening platform for field experiments. Mortality rates of females and eggs depended on the applied treatment formulation and fungal strain. Velifer®, a Beauveria bassiana product, and Metarhizium brunneum (Mb7) resulted in 60-88% female mortality. Mb7-as a conidial suspension or powder-resulted in 18-21% egg-hatching rates, approximately 3 times less than in the non-treated control. Treating palms with Mb7 suspension or dry formulation significantly inhibits infestation signs and results in protection. These results lay the foundation for investigating the protective rate of EPF products against RPW in date plantations.

Laboratory evaluation of selected botanicals and insecticides against invasive Spodoptera frugiperda (Lepidoptera: Noctuidae)

BackgroundMaize is an economical crop of China, and its production has been severely affected by the invasive Spodoptera frugiperda in recent year. Application of synthetic pesticides are one of the most effective practices against FAW as an emergency control. This pest causes serious damage to the maize crop worldwide in recent decade, especially in China. MethodsTo find an alternative to synthetic insecticides there were total 16 different chemicals were used including ten botanical insecticides comprising of seven botanicals, azadirachtin, pyrethrin, nicotine, osthole, rotenone, Celastrus angulatus, matrine, and three insect growth regulators, diflubenzuron, lufenuron and buprofezin. Six synthetic insecticides, including emamectin benzoate, indoxacarb, imidacloprid and thiamethoxan, chlorantraniliprole, chlorfenapyr, were evaluated against 2nd instar of S. frugiperda larvae using leaf-dip method. ResultsThe results revealed that osthole, azadirachtin, buprofezin and pyrethrin were showed the significant larval mortality of 98.0, 96.7, 94.0 and 90.7%, in 120 h observation and exhibiting minimum LC50 (39.04, 35.58, 61.45 and 48.46 mg/L, respectively) and LT50 (48.91, 68.85, 58.67 and 58.57 h, respectively) values. Among tested synthetic insecticides, emamectin benzoate, chlorantraniliprole and chlorfenapyr were showed significant higher mortality against larvae of S. frugiperda (99.3, 96.0 and 89.3%, respectively) in 72 h observation by exhibiting minimum LC50 (0.26, 0.39 and 0.72 mg/L, respectively) and and LT50 (10.18, 10.57 and 13.42 h, respectively) values. More study is needed to test the laboratory findings in the field, although the efficient biorational pesticides might be utilized as part of integrated pest management against S. frugiperda. ConclusionThe effective chemicals could be used in the management for S. frugiperda. The highest discriminating concentrations of tested botanical insecticides, insect growth regulators and insecticides caused significant mortality of S. frugiperda larvae.

The effects of herbicide application on two soil phosphate solubilizing bacteria: Pantoea agglomerans and Serratia rubidaea.

The application of synthetic pesticides is one of the fastest acting tools at farmers' disposal to prevent and mitigate the threats posed by plant pests in agriculture. However, the effects of these above-ground applications of pesticides are known to be detrimental to some belowground, non-target soil biota. At present, the effects many pesticides have on key functional microbial groups associated with phosphate (P) solubilization in the soil are still largely unknown. The purpose of this study was to compare the effects of two herbicides, glyphosate, and paraquat, on phosphate solubilizing bacteria (PSB) with and without pH adjustment (after herbicide addition) since pH is a major indicator of P solubilization. In our assay, two PSB strains (Pantoea agglomerans and Serratia rubidaea) were chosen to assess their ability to solubilize tricalcium phosphate (TCP) by using the vanadate-molybdate method (to measure the amount of P solubilized) in the presence of glyphosate (5.4 g/L and 10.8 g/L) or paraquat (2 g/L and 4 g/L) separately. To assess the effect of PSB treated by the herbicides, a growth experiment using PSB inoculated wheat seedlings was performed under greenhouse conditions (25 °C, light 16 h/8 h dark). After four weeks, wheat above-ground growth parameters were measured. Our results showed that even under recommended doses of glyphosate (5.4 g/L) and paraquat (2 g/L), a decrease in P solubilization activity was observed in P. agglomerans and S. rubidaea. Whilst paraquat affected TCP solubilization more than glyphosate with and without pH adjustment, there was a significant decrease (p < 0.05) in TCP solubilization, up to 39% and 93% in the presence of glyphosate and paraquat, respectively, for S. rubidaea, and up to 45% and 95% in the presence of glyphosate and paraquat, respectively, for P. agglomerans. The effect of the herbicides on the PSB had the same results as in the greenhouse test on wheat seedling growth, confirming that these herbicides have both above and belowground negative effects, despite being used at recommended doses.

Eco-friendly management of the flea beetle, &lt;i&gt;Podagrica&lt;/i&gt; species (Coleoptera: Chrysomelidae) on okra (&lt;i&gt;Abelmoschus esculentus&lt;/i&gt; (L.) Moench) with &lt;i&gt;Artemisia annua&lt;/i&gt; L. seed extract

&lt;p&gt;Okra, grown and consumed in every ecological zone, is amongst the most sort after fruit vegetable crops in Nigeria. The crop is often infested by diverse field insect pests, especially the flea beetle &lt;em&gt;Podagrica&lt;/em&gt; species, which impinges on its growth and productivity. The application of synthetic pesticides has been the generic insect pest control measure due to its touted effectiveness. These synthetics, however, has safety concerns which include; hazard to human health, amplification of toxins in the food chain, pest resurgence, domestic animals and human poisoning, environmental pollution, insect resistance, natural enemies destruction; springs, wells, rivers, and underground water contamination. Stakeholders are advocating an alternative management approach that is sustainable with less negative social and environmental impact. This study, therefore, compared the insecticidal efficacy of &lt;em&gt;Artemisia annua&lt;/em&gt; (source of the antimalarial artemisinin) seed extract in comparison with Cypermethrin 10 EC, a synthetic insecticide, in controlling &lt;em&gt;Podagrica&lt;/em&gt; species, the major field insect pests of okra. The trial was set out in a 7 x 4 factorial arrangement integrated into a randomized complete block design and replicated thrice. Cypermethrin 10 E.C was tested at 0.25 ml, 0.50 ml, and 0.70 ml/100 ml of water, while &lt;em&gt;Artemisia annua&lt;/em&gt; extract was applied at 1.00 ml, 2.00 ml, and 3.00 ml/100 ml of water respectively. The control for both treatments was designated 0.0 ml. Data on leaf damage and flea beetle abundance were carried out from 4-10 weeks after planting (WAP) whilst the pods’ weight was measured at maturity. The result shows that i) the concentrations of Artemisia extract and Cypermethrin sprayed provided comparable protection to okra against the flea beetle; ii) the yield of okra (pod weight) does not vary between &lt;em&gt;Artemisia annua&lt;/em&gt; extract and Cypermethrin treated plots; and iii) flea beetle infestations vary with okra developmental stages.&lt;/p&gt;

ANTIFUNGAL ACTIVITY OF VOLATILE ORGANIC COMPOUNDS (VOC) BY AN ENDOPHYTIC FUNGUS, Lasiodiplodia avicenniae P2P4 FROM Avicennia alba AGAINST Fusarium oxysporum

Fusarium oxysporum is a significant phytopathogenic fungus in the agricultural sector which causes a substantial loss to the yield of commercial crops and economical benefits. The fungal species is a primary agent of vascular wilt diseases on various crops that are currently mitigated through the application of synthetic pesticides. The prolonged use of synthetic pesticides may lead to the initiation of microbial resistance to pesticides despite their other detrimental effects on the environment and human health. Biopesticides are safer bioproducts that can be applied to hinder F. oxysporum growth with varying efficacy and mechanism of action. This study deals with the investigation of volatile organic compounds (VOCs) produced by an endophytic manglicolous fungus as one of the potential biopesticides to control F. oxysporum. Lasiodiplodia avicenniae P2P4 was isolated from the pneumatophore of Avicennia alba growing in the mangrove forest near Belawan City, North Sumatra, Indonesia, and was tested for its antifungal activity against F. oxysporum using poison food technique. The highest inhibition (&gt;80%) was observed from 1000 ppm treatment with an effective concentration (EC50) value of 888.228 ppm after 7 d of incubation. GC-MS analysis of the EtOAc extract of L. avicenniae P2P4 revealed a mixture of volatile and non-volatile organic compounds (27 in total). Acetic acid, glycerol, and 1,3/2,3-Butanediol were identified as the major portion of compounds in the extract that could be responsible for its antifungal activity against F. oxysporum.

Attraction of leaf hopper, Amrasca biguttulla biguttulla, and whitefly, Bemisia tabaci, toward natural essential oils in cotton

Abstract Leaf hopper, Amrasca biguttula biguttula, and whitefly, Bemisia tabaci are the most economical sucking pests of cotton (Gossypium spp.) causing stunting, shortening of internodes and transmitting plant pathogenic viruses. The management of these pests is primarily based on application of synthetic pesticides, which not only triggers resistance to insecticide molecules but also contributes to environmental pollution. We aimed to study the attraction of A. biguttula and B. tabaci toward six natural essential oils (NEOs) viz., sandalwood, basil, grapefruit, rose, clove and mint oils using yellow sticky traps under field conditions. The results showed that traps treated with sandalwood and basil oils attract significant numbers of A. biguttula and B. tabaci as compared to the other traps during the seasons 2016-2017 and 2017-2018. Further, the Attractive Index (AI) of sandalwood and basil oils to these pests were significantly higher (i.e., &gt;1). In addition, the traps treated with sandalwood and basil oils caught relatively lower numbers of natural enemies. The GC-MS analysis specified the presence of vital attractive volatile compounds, viz., santalene, funebrene and pentadecane in sandalwood; and linalool, β-farnesene, caryophyllene and methyl eugenol in basil oil. Based on the results obtained it can be concluded that application of sandalwood and basil oils increased the attracting efficacy of sticky traps for the management of A. biguttula and B. tabaci in cotton.

Integrated Pest Management Strategies for Asian Citrus Psyllid Diaphorina citri Kuwayama (Hemiptera: Psyllidae) and Huanglongbing in Citrus for Sarawak, East Malaysia, Borneo.

Simple SummaryThe severe Asian form of huanglongbing is the most serious disease of citrus in Malaysia. It is caused by a phloem-limited bacterium ‘Candidatus Liberibacter asiaticus’ and transmitted by the Asian citrus psyllid, Diaphorina citri Kuwayama. Minimising the devastating impacts of the disease requires effective integrated pest management (IPM) programs to limit detrimental environmental and health consequences of over-reliance on synthetic pesticides. Key components of such programs include grower awareness, planting of pathogen-free trees, monitoring psyllid and disease incidence, removal of diseased trees, and judicious use of insecticides, mineral oils, and natural enemies to suppress incidence of the psyllid. Significant progress has been made towards implementing the programs.The Asian citrus psyllid (ACP), Diaphorina citri Kuwayama, transmits ‘Candidatus Liberibacter asiaticus’ (CLas), a phloem-limited bacterium associated with the severe Asian form of huanglongbing (HLB), and the most destructive disease of citrus. The pathogen and the psyllid, both of South Asian origin, are now widespread in citrus regions of Asia and the Americas. There is no cure for the disease. Application of synthetic pesticides, in some instances more frequently than fortnightly, to minimise incidence of ACP in citrus orchards, has not prevented inevitable impacts of the disease in regions of Asia where CLas is present. Despite the inevitable spread of the disease, significant progress has been made in Sarawak since the mid-1990s towards effectively implementing integrated pest management (IPM) programs for stemming the impact of the disease and detrimental consequences of over-reliance on synthetic pesticides. Growers are encouraged to plant pathogen-free trees, remove diseased trees, monitor incidence of the psyllid, and to use pesticides judiciously to reduce their detrimental impacts on natural enemies. Knowledge has been enhanced through research on seasonal incidence of the psyllid, use of mineral oils, development of protocols and iodine–starch test kits for detecting infected trees, PCR for confirming the presence of CLas in symptomatic leaves, methods for monitoring incidence the psyllid, and training extension staff and growers. However, major impediments to increasing the average longevity of trees beyond <5 years in poorly managed orchards, based on marcotting (air layering), and >12 years in well-managed orchards, based on pathogen-free trees, still need to be addressed. These include grower knowledge, marcotting, aggressive marketing of synthetic pesticides, high prices of mineral oils, spray application procedures, and better reliance on natural enemies of the psyllid.

Efficacy of antifungal substances of three Streptomyces spp. against different plant pathogenic fungi

BackgroundSoil-borne plant pathogenic fungi with a wide host range of crops cause a significant limitation on the global production of agronomic crops. Applications of synthetic pesticides are an important tool for managing plant diseases, but have deleterious influences on the environment as well as its incompatibility with organic agriculture. Recently, Streptomyces spp. became one of the best bio-control agents as a promising environmentally eco-friendly method for effective management of plant diseases.ResultsIn a previous research, three species of Streptomyces spp., i.e., S. griseus (MT210913 “DG5”), S. rochei (MN700192 “DG4”) and S. sampsonii (MN700191 “DG1” strains) were identified, as exhibiting potent antifungal activities against plant pathogenic fungus, Sclerotinia sclerotiorum in vitro and greenhouse. GC–Mass analysis revealed the presence of 44, 47 and 54 substances of S. sampsonii DG1, S. griseus DG5 and S. rochei DG4, respectively. GC–MS revealed substances, with bio-control activity, were categorized as volatile organic compounds (VOCs), fatty acids and plant growth regulators, etc. GC–MS analysis exhibited the presence of 7, 13 and 20 volatile compounds produced by S. sampsonii, S. rochei and S. griseus, respectively. These substances exhibited potent antifungal activity against various plant pathogenic fungi, i.e., Botrytis cinerea, Macrophomina phaseolina, Rhizoctonia solani and S. sclerotiorum in vitro, by dual-culture assay. The three strains inhibited all the pathogenic fungi in dual-culture assay in the range of 30–73.67%. Also, the produced substances were applied in vivo (in the field) and supported their potential biocontrol agent against S. sclerotiorum as well as possessed significant biological properties for plant health and growth. Applying Streptomyces spp. culture broth in the field enhanced physiological responses of phenols, sugar, chlorophyll, protein contents and parameters as well as the yield of bean plants.ConclusionIn field experiments, foliar application of Streptomyces spp. and their metabolites proved to be a great potential, as promising biocontrol agents, for controlling S. sclerotiorum and enhanced plant growth and yield. S. rochei and S. griseus proved to be strong antifungal, plant growth promoters and environmentally eco-friendly fungicides.

Biocontrol potential of Pseudomonas stutzeri endophyte from Withania somnifera (Ashwagandha) seed extract against pathogenic Fusarium oxysporum and Rhizoctonia solani

Agricultural crops are susceptible to abiotic and biotic factors. Among biotic factors, plant pathogens attacks are prominent and significantly reduce the crop productivity and production. Long term application of synthetic pesticides in agriculture not only causes resistance development in pathogens but also deteriorates the soil quality and pollutes the ecosystem. In the current study, an investigation has been made with an objective to isolate an endophytic bacterium from Withania somnifera seed and evaluate its potential biocontrol activity against soil-borne pathogens like Fusarium oxysporum var. ciceri and Rhizoctonia solani. The molecular approach of bacterium identification using 16S rRNA sequencing methods includes kit based DNA extraction and PCR amplification and the isolated endophytic bacterium was identified as Pseudomonas stutzeri. In dual culture assay, the endophytic bacterium P. stutzeri PSIISS-1 effectively suppressed growth of pathogenic fungi F. oxysporum var. ciceri (61.0%) and R. solani (53.3%), respectively. In vivo studies were conducted with initial microbial inoculum size of 108cell/ml and the studies revealed that the bacterium P. stutzeri PSIISS-1 co-inoculated with R. solani had significantly inhibited the sheath blight disease with the efficacy of 76% in susceptible paddy MTU-7029. Simultaneously, co-inoculation of P. stutzeri PSIISS-1 along with the pathogen F. oxysporum var. ciceri in chickpea JG-14 variety resulted in reduction of wilt symptom up to 80.45%. Bacterial inhibitions against the pathogens were corroborated with chitinase, protease and lipase enzymatic activities. Based on the results obtained from the study, P. stutzeri showed biocontrol activity against plant pathogens which can be used as potential bio-pesticides.

Plant powders protect stored wheat from infestation by lesser grain borer Rhyzopertha dominica (fabricius) (Bostrichidae: Coleoptera)

Rhyzopertha dominica (Bostrichidae: Coleoptera) is one of the most serious devastating insect pests attacking stored wheat grains in Nigeria. The most common strategy adopted in controlling this insect pest is the application of synthetic pesticides which is costly, toxic to non-target organisms and is non eco-friendly. Botanical pesticides are recently used as alternatives to synthetic pesticides due to their non-hazardous effect on the environment and non-target organisms, cost effectiveness and direct impacts on the target organisms. This study was carried out to determine the toxicity of leaf powders obtained from three species of plants: Ageratum conyzoides, Momordica charantia and Tephrosia vogelii in the control of R. dominica infestation on stored wheat grains. Five doses (0.50, 1.00, 2.00, 4.00 and 8.00 g) per 20.00 g were measured from the powdered leaves of the tested plants with ethanol treatment as the control (0.00 g 20.00 g-1). The powdered doses were applied onto wheat grains before the insects were introduced. The experiment was laid down in completely randomized design (CRD) with three replications. The data obtained was analyzed using analysis of variance at 5% probability level with Least Significant Difference used to separate the means. The results showed significant (p ≤ 0.05) differences in the magnitude of toxicity imparted by various doses of the powders on R. dominica. The treatments influence high rate of mortality, reduced number of laid eggs and emerged adults when compared with the control. The toxicity of the powders increased with increase in dosage. It was concluded that 8.00 g 20.00 g-1 of the powders were more toxic to R. dominica, inducing 28.00-77.30% insects’ mortality thereby protecting grain damage to as low as 1.04% at 6th month of storage. T. vogelii leaf powders were recommended for use against R. dominica in stored wheat grains.&#x0D; Key words: botanicals, dose, lesser grain borer, wheat

Mycobiome Transplant Increases Resistance toAustropuccinia psidiiin an Endangered Hawaiian Plant

The accelerated global movement of plant pathogens has become a substantial threat to rare and endangered plants. Although application of synthetic pesticides on endangered plants is often necessary to control disease in greenhouse settings, these chemical treatments degrade the leaf microbiome. This reduction in diversity can eliminate foliar microbes that are essential for pathogen resistance, making plant hosts more susceptible to disease once outplanted in the wild. Beneficial microbes that naturally occur in plant tissue are a resource that is quickly gaining traction as a viable means to increase plant fitness and pathogen resistance in both agricultural and wild habitats. This is of particular interest for threatened and endangered wild plant populations with limited genetic variation where breeding for resistance is not possible. In this experiment, we tested the effectiveness of microbial inoculations to inhibit the fungal pathogen Austropuccinia psidii, which is currently threatening the critically endangered Hawaiian Eugenia koolauensis with extinction. Using molecular and culture-based methods, we characterize foliar fungal communities of Myrtaceous hosts resistant to A. psidii and introduced these diverse fungi into the microbiome of E. koolauensis leaves. Our results indicate that transplanting an intact mycobiome community is more effective at reducing foliar disease resistance when compared with single-fungal-species inocula. These findings demonstrate the potential of whole-microbiome transplants as a powerful tool to inducing disease resistance and enhancing plant health within a conservation context.

Plant botanicals as controlling agents against pests Sitophilus oryzae and Callosobruchus chinensis: A review

Agriculture is adversely affected by numerous insects and pests, nematodes, and invasive weeds. It reduces the yield and produces low-quality grains by 5% of world food production. Stored grain pests are the primary cause of decreased quality, seed viability, grain weight, and commercial value. Chemical pesticides and insecticides proved to be effective and cheaper. The use of chemical pesticides and insecticides harms the environment by affecting soil fertility, developing resistance in pests through genetic variations, and increasing toxic residues. Botanical insecticides cost-effective, biodegradable, and eco-friendly. Botanical insecticides can never entirely replace synthetic pesticide production, but they may solve problems associated with the application of synthetic pesticides. This review summarises the use of plant botanicals as controlling agents against pests Sitophilus oryzae and Callosobruchus chinensis .

Pengembangan teknologi pengendalian hama utama kacang hijau menggunakan biopestisida

Hama merupakan salah satu kendala utama dalam upaya peningkatan produksi kacang hijau di Indonesia. Saat ini, pengendalian konvensional menggunakan pestisida sintetik kurang berhasil karena populasi dan kerusakan akibat hama masih tinggi. Penelitian ini bertujuan untuk mengembangkan biopestisida sebagai teknologi pengendalian hama utama kacang hijau yang dibandingkan dengan efikasi pestisida sintetik. Penelitian ini dilaksanakan menggunakan rancangan acak kelompok, lima perlakuan diulang lima kali. Perlakuan yang diuji, yaitu P1: aplikasi serbuk biji mimba (SBM), virus ulat grayak (Virgra) dari Spodoptera litura nuclear polyhedrosis virus, dan konidia cendawan entomopatogen Beauveria bassiana (BeBas) secara preventif; P2: aplikasi SBM, Virgra, dan BeBas berdasarkan ambang ekonomi (AE); P3: aplikasi pestisida sintetik sesuai jadwal; P4: aplikasi pestisida sintetik berdasarkan AE; dan P5: tanpa pengendalian (kontrol). Hasil penelitian menunjukkan bahwa hama yang berkembang adalah ulat grayak (Spodoptera litura (Fabricius)), kutukebul (Bemisia tabaci (Gennadius)), Empoasca sp., Megalurothrips usitatus (Bagnall), kepik coklat (Riptortus linearis (Fabricius)), kepik hijau (Nezara viridula (Linnaeus)), dan hama penggerek polong (Maruca testulalis (Geyer)). Aplikasi biopestisida SBM, Virgra, dan BeBas secara preventif dan aplikasi pestisida sintetik sesuai jadwal efektif menekan populasi hama utama kacang hijau, sedangkan aplikasi biopestisida dan pestisida sintetik berdasarkan AE tidak mampu menekan perkembangan populasi hama utama. Aplikasi biopestisida secara preventif maupun berdasarkan AE lebih aman terhadap kelangsungan hidup musuh alami, sedangkan aplikasi pestisida sintetik dapat membunuh musuh alami yang ada. Biopestisida SBM, Virgra, dan BeBas yang diaplikasikan secara preventif dan terintegrasi berpotensi sebagai inovasi teknologi pengendalian hama utama kacang hijau untuk menggantikan pestisida sintetik.

Modulations in growth, structure, cell viability and antioxidant enzyme of a nodule bacterium Mesorhizobium ciceri induced by pesticides

A rapid increase in the application of synthetic pesticides in agricultural practices causes a severe hazard to agro-sustainability and soil microflora. Considering these threatening problems, the present study aimed to investigate the impact of different groups of pesticides on growth, cellular morphostructure, permeability and antioxidant enzyme of a symbiotic Gram-negative bacterium recovered from chickpea nodules. Pesticide-tolerant strain BRM5 was characterized and phylogenetically (accession no. KY013481) identified as Mesorhizobium ciceri. Strain BRM5 tolerated up to the level of 1200, 1600, 1600, 2400, 2400, 1800, 2400, 2400 and 3200 μg mL−1 of glyphosate, quizalofop, atrazine, kitazin, metalaxyl, hexaconazole, fipronil, monocrotophos and imidacloprid, respectively. Among all concentrations, 3X concentrations of each pesticide had most fatal to bacterial cells. The growth pattern of strain BRM5 was decreased linearly with increasing incubation times. Scanning electron micrograph (SEM) images of pesticide-treated bacterial cells revealed the distorted, broken, irregular, misshaped and larger-sized cell as compared to untreated cells. Upon staining with acridine orange (AO)/propidium iodide (PI), active/living cells appeared as green colour, whereas dead cells appeared as red colour under confocal microscope (CLSM). This is the clear indication of loss in cell viability following the pesticide exposure. The generation of oxidative stress (catalase) by strain BRM5 induced under pesticides pressure further revealed the pesticidal toxicity. CAT activity of BRM5 was decreased with the enhancement in pesticide concentrations. For instance, CAT activity of BRM5 was decreased by 45%, 71% and 83% when cultured in liquid medium treated with 3X doses of each glyphosate, kitazin and fipronil, respectively. Overall, the present study visibly indicated that pesticides inhibited the growth, disrupted the morphology and reduced the permeability and antioxidant producing ability of bacteria. So, from this study, it is suggested that before applying the pesticides in legume production strategies, the recommended pesticides be carefully examined to avoid the toxicity problems, if any.

Acalypha wilkesiana: prospects as an agricultural biocide

The dynamism of global trade and a changing climate has aided the threats posed by plant pests and diseases on food security. Combating the long-standing challenges posed by pests and diseases has been a frontline issue among the various stakeholders in the agricultural food value chain. Investment in newer synthetic pesticides with increased selectivity towards target pests and decreased toxicity to mammals, the introduction of genetically-modified crops, and development of automated technology for early detection and monitoring of pest population are some 21st-century research advancements to curb the menace. In Africa, agriculture lies majorly in the hands of smallholding farmers, and most of them live below the poverty line and cannot afford these expensive modern technologies. Documented reports over decades have also revealed that the average farmer in Africa relies solely on the use of synthetic pesticides to combat pests and disease problems. Their complacency and indiscriminate application of synthetic pesticides have resulted in deleterious impacts on non-targeted organisms, human health, and the environment. The clarion call has been towards the search for panaceas which eschew the use of synthetic pesticides and promote food safety and security. Plants have been documented with an extensive reservoir of under-tapped and un-tapped bioactive compounds for chemical and biological studies. These plants have been proven efficacious in the management of crop pests and diseases, are readily biodegradable, and with low toxicity on non-target organisms. Acalypha wilkesiana is one of these plants whose information on its application as an agricultural biocide is limited. Therefore this review explores available information on the broad spectrum potentials embedded in the plant, intending to promote its application as an agricultural biocide.

Direct and indirect effects of plant diversity and phenoxy herbicide application on the development and reproduction of a polyphagous herbivore

Widespread application of synthetic pesticides and loss of plant diversity are regarded as significant drivers of current global change. The effects of such phenomena on insect performance have been extensively studied separately, yet the interactions of these two drivers have been poorly explored. Here, we subjected the polyphagous grasshopper Pseudochorthippus parallelus (Zetterstedt, 1821) to a full-lifecycle field experiment with 50 cages containing experimental plant communities differing in grass species richness (2 vs. 8 grass species), half of them treated with a phenoxy herbicide commonly employed to control broadleaf plants in grasslands. We measured plant elemental content as a proxy for plant physiology, and a wide range of insect traits in both female and male grasshoppers. In females, grass diversity increased herbivory, insect nitrogen content and egg load, while herbicide reduced herbivory but increased the number of offspring, likely mediated by altered plant community composition. In males, grass diversity also increased herbivory, had positive effects on fat body, muscle volume and lifespan, and negative effects on body mass. Herbicide negatively affected herbivory in both females and males. Overall, plant diversity and herbicides may shift resource allocation in generalist terrestrial insect herbivores, indicating complex and unexpected effects of human-induced environmental change.

The Diversity of Insect in Paddy Field in Karawang, West Java with Different Pest Management Techniques

The practice of rice crop cultivation will affect the trophic structure and the diversity of insects that are formed. One of the common cultivation practices carried out by farmers was the control of pests by using pesticides. This study aimed to find out which pest management strategies that are effective in maintaining environmental health and understanding how natural enemies were affected by the application of synthetic pesticides. The first treatment was paddy field with integrated pest management (IPM), the second treatment was conventional rice field with a technique of chemical pest management (C-T), while the third treatment was mixed pest management (M-T). Insect sampling was conducted using sweep net, pitfall trap, and direct observation for 10 weeks after planting. Overall, it was found 100 morphospecies, 9 Orders, 56 families, with a total abundance of 6242 individuals per planting season. Based on functional roles it was found 39% as herbivores, 30% as predators, and 14% as parasitoids, 1% pollinators, and 13% decomposers. High insect diversity and abundance were found in the plots using low synthetic pesticides. The C-T control plot had a lower relative abundance of herbivorous insects, parasitoid insects, predators, and decomposers than the other control plots. H' and D index in the Integrated Pest Management (IPM) and Mixed Pest Management (M-T) plots did not show significant differences but differed significantly from the Chemical Control plot (C-T). Therefore, controlling the herbivore insects could apply the pest management based on IPM strategies. Keywords: Diversity of insects, integrated pest management (IPM), natural enemies, pesticides, rice pests

Toxic assessment, growth disrupting and neurotoxic effects of red seaweeds' botanicals against the dengue vector mosquito Aedes aegypti L.

Application of synthetic pesticides over decades to control insects, pests, and disease vectors has resulted in negative impacts on environment and health. The current study assessed the toxicological effects of 12 botanicals obtained from 4 different red seaweeds against the dengue vector mosquito Aedes aegypti L. (Diptera: Culicidae). Four species of red seaweeds, namely Laurencia karachiana, Gracilaria foliifera, Jania rubens, Asparagopsis taxiformis, were collected from Karachi coast and extracted with hexane, dichloromethane and methanol. The efficiency of these extracts was determined by using a dose-response bioassay method against 4th instar larvae of Ae. aegypti. Separate investigations on the toxicity and IGI effects were done. Comparative studies showed that the hexane extracts induced more toxic effects. Based on the LC50 values, obtained after 24h of treatments, hexane extract of J. rubens (HJ) exhibited toxic effects with LC50 32μg/mL, (equivalent to GHS category 3), followed by G. foliifera (HG) (LC50 76.8μg/mL). HJ also showed prominent neurotoxic effects within 1-6h. Comparatively, higher morphological abnormalities and growth inhibiting (IGI) effects were obtained in the dichloromethane and methanol extracts treated larvae, after 48-96h, resulting in the formation of immature life forms such as larvi-pupae and pupi-adult. Presumptive growth inhibiting effects were also noted. These included formation of albino and black pupae, deformities in the internal structure of the treated larvae and the chitin synthesis related effects such as 'inhibiting effect on adult emergence'. Finding revealed that red seaweeds, harvested from the Arabian Sea, have potentials to affect Ae. aegypti survival and thus can be utilized as green pesticides.