Use Of Synthetic Pesticides Research Articles

The odorant receptor co-receptor gene contributes to mating and host-searching behaviors in parasitoid wasps.

Biological control of pest insects by parasitoid wasps is an effective and environmentally friendly strategy compared with the use of synthetic pesticides. Successful courtship and host-search behaviors of parasitoid wasps are important for biological control efficiency and are often mediated by chemical odorant cues. The odorant receptor co-receptor (Orco) gene has an essential role in the perception of odors in insects. However, the function of Orco in the mating and host-searching behaviors of parasitoid wasps remains underexplored. We identified the full-length Orco genes of four Drosophila parasitoid species in the genus Leptopilina, namely L. heterotoma, L. boulardi, L. syphax and L. drosophilae. Sequence alignment and membrane-topology analysis showed that Leptopilina Orcos had similar amino acid sequences and topology structures. Phylogenetic analysis revealed that Leptopilina Orcos were highly conserved. Furthermore, the results of quantitative real-time polymerase chain reactions showed that all four Orco genes had a typical antennae-biased tissue expression pattern. After knockdown of Orco in these different parasitoid species, we found that Orco-deficient male parasitoid wasps, but not females, lost their courtship ability. Moreover, Orco-deficient female parasitoid wasps presented impaired host-searching performance and decreased oviposition rates. Our study demonstrates that Orcos are essential in the mating and host-searching behaviors of parasitoid wasps. To our knowledge, this is the first time that the functions of Orco genes have been characterized in parasitoid wasps, which broadens our understanding of the chemoreception basis of parasitoid wasps and contributes to developing advanced pest management strategies. © 2022 Society of Chemical Industry.

Mesofauna as effective indicators of soil quality differences in the agricultural systems of central Cuba

Soil mesofauna play an essential role in soil functioning. However, in studies on the impact of agricultural management on soil quality, the overall abundance of soil mesofauna and specific groups thereof has not been widely used as an indicator in developing countries. Here, we used soil mesofauna as a soil quality indicator compared to more traditional soil chemical, physical, and microbial indicators, in a comparison of the impact of three diverse agricultural management systems in Central Cuba: state (CSt), conventional private (CPr), and organic private (OPr) farms. We sampled the top 20 cm of soil of 30 fields from 12 farms and 1 natural reference site (NR) and analysed a number of soil chemical, physical, and microbial soil parameters as well as mesofauna (Acari and Collembola, further subdivided into Mesostigmata–Prostigmata–Oribatida–Astigmata and Isotomidae–Entomobryidae, respectively). Differences in soil properties between agricultural fields and natural soil were observed (especially in the multivariate analysis), but no significant differences were observed between agricultural systems, probably due to a lack of differences in soil organic carbon (SOC) content. The mesofauna differed strongly between the NR and the two conventional management practices (CSt and CPr), both in total numbers and in group numbers for most groups and in both rainy and dry seasons, whereas there were almost no significant differences between NR and OPr. Principal component analysis based on mesofauna clearly distinguished NR from all farming systems and OPr from CSt and CPr. Differences in soil mesofauna were mainly attributed to the use of synthetic pesticides. We conclude that in this context, without clear differences in SOC content between agricultural fields, mesofauna is a superior soil quality indicator. Our results indicate that simple counts of total abundance are as useful as counts of specific mesofauna groups irrespective of the sampling period (dry or wet season).

Food sovereignty in sub-Saharan Africa: Reality, relevance, and practicality

The recent discourse on food sovereignty places much emphasis on democracy in determining localized food systems, and whether the food is culturally appropriate while leaning heavily on sustainable agricultural practices such as organic agriculture, ecological intensification, agroecology, nature-based solutions, and regenerative agriculture. Sustainable agricultural practices are intended to ensure that the land is managed without the use of synthetic fertilizers and pesticides, while going further by focusing on improvements on soil and land health. However, what are the practicalities of food activism and relying entirely on nature while yields are still very low in much of sub-Saharan Africa (SSA)? We attempt to answer this question in four main sections: (a) we start by defining the concept of food sovereignty and the associated practices, (b) we highlight some of the main socio-ecological conditions that are common in SSA, and (c) we present evidence of some of the limitations of food sovereignty due to the diversity in ecological, political, cultural, and socio-economic contexts that characterize SSA; finally, (d) we focus on food preferences, marketing and certification aspects. We conclude that agroecology alone cannot solve the multiple objectives of increasing crop productivity and replenishing soil nutrients especially on small farms and relying on natural rainfall. There is an urgent need to combine superior crop varieties and judicious use of external inputs in tandem with the manipulation of the agroecological processes to increase the efficiency of input use and achieve higher food productivity, resilience to climate change, and preservation of the natural resource base in specific locations.

Extract yield, dilution methods and antifungal potential of fruits of Picralima nitida (Stapf.) T. A. Durand & H. Durand

Today, despite its status as a key sector, agriculture faces many problems due to fungi and the use of synthetic pesticides. This study evaluated the antifungal potential of Picralima nitida fruits against Fusarium oxysporum . The extracts were obtained by the Total Aqueous Extraction method (TEA) and Hydroethanolic extraction (EE70%) method. Two dilution types of the extracts in PDA medium were tested: (1) dilution before autoclaving (AvA) and (2) dilution after autoclaving (ApA). The extracts of two fruit morphotypes from two climatic zones were tested at a concentration of 3 mg.ml −1 . The yield of fruit extracts from Dahomey Gap (DG) was significantly higher (>8%) than that from the Guinea-Congolese region (GC). A significant difference was observed in yield (p < 0.05) between TEA type and the EE70% type with a higher inhibition rate (27%) of EE70% on Fusarium oxysporum. No significant difference was observed between the pathogen inhibition rates in the dilution type (p > 0.05). The inhibition rate of the pathogen was 25.65% for the short fruit morphotype and 25.08% for the large fruit morphotype. This study demonstrated possibility of using extracts of Picralima nitida in agriculture.

Environmental Safety and Ecotoxicity of Biopesticides

The growing increase in the world population, associated with increased demand for food, has promoted the increased use of synthetic Plant Protection Products (PPPs as pesticides) in agriculture, which can raise environmental concerns. Nowadays, it is generally believed that the use of Biopesticides (BioPPPs) may contribute to reducing the undesirable environmental effects usually associated with the use of synthetic pesticides. However, the risk assessment required by the EU Member States Authorities (EMSA) to evaluate the ecotoxicity of PPPs may not be the most suitable for BioPPPs due to their particular properties and mode of action that are distinct from those of synthetic PPPs.

The effect of integrated pest management on Scirpophaga innotata population and natural enemies on rice field in South Sulawesi, Indonesia

Abstract. Rahmawasiah, Abadi AL, Mudjiono G, Rizali A. 2022. The effect of integrated pest management on Scirpophaga innotata population and natural enemies on rice field in South Sulawesi, Indonesia. Biodiversitas 23: 4510-4516. White rice stem borer, Scirpophaga innotata, is an important pest on rice plants that needs attention because the population is quite large in Luwu Raya. This pest attacks rice plants at all growth stages and can result in yield losses in rice production. Synthetic insecticides are a common control technique used by farmers to control these pests. The continuous use of pesticides will certainly have a negative impact. Therefore, pursuing effective control strategies and maintaining environmental sustainability is necessary. This study aimed to determine the white rice stem borer population and its natural enemies on rainfed land, and permanent irrigated lands managed conventionally and integrated pest management. The research was carried out using insect sampling techniques and calculating the white rice stem borer population and natural enemies in rice cultivation. In rainfed and irrigated rice fields, rice cultivation was carried out using conventional methods and integrated pest management (in the form of planting refugia and regulating the use of synthetic pesticides). The sampling was carried out on plants from the vegetative phase to the generative phase. The type of insect taken was the white rice stem borer in the form of collecting groups of eggs and larvae. Imago was observed visually and using a farmcop. In addition, the collection of natural enemy insects on the plantation was also carried out. The results showed that the application of the integrated pest management system caused no significant effect on the decline of the white rice stem borer population in both rainfed and permanently irrigated lands in Luwu Raya. The white rice stem borer population was more commonly found in rainfed land than permanently irrigated land. The parasitoids found were Telenomus rowani, Tetrastichus schoenobii and Trichogramma japonicum. The population of Telenomus rowani was more numerous than other types of parasitoids. On average, the parasitoid population was more in the land managed by integrated pest management (IPM) application than the conventionally managed land. The predators found on the land were Oxyopes javanus, Agriocnemis femina, Conocephalus longipennis, Menochilus sexmaculata, Ophionea nigrofasciata, Micraspis lineata, and Paederus fuscipes. Predator populations were more on land managed with the application of IPM than on land managed conventionally.

Histopathological effects of methomyl and crude extracts of Jatropha curcas against the terrestrial snail, Monacha obstructa (Gastropoda:Hygromiidae)

BackgroundThe negative effect of over-reliance on the use of synthetic pesticides have led to the search for natural alternatives to pest control. This study was designed to evaluate the toxicity effect of the crude plant extracts of Jatropha (Jatropha curcas Linn.) seeds in comparison with methomyl on some histopathological changes of the terrestrial snail species Monacha obstructa (Pfeiffer, 1842). The toxicity effect of methomyl and crude extracts of ethanol and acetone extracts of Jatropha curcas seeds were determined on some histological changes of the land snail, Monacha obstructa at four concentrations using the contact technique under laboratory conditions.ResultsThe results revealed that the crude extracts of Jatropha exhibited obvious adequate effects compared with methomyl against M. obstructa land snails. The highest toxicity effects were obtained by methomyl followed by the ethanolic extract of Jatropha and hexane extract of Jatropha. The histopathological effect of LC50 of Jatropha crude extract and methomyl on the digestive gland and foot tissues were examined in the land snails M. obstructa. The treated snails showed several histological changes in the digestive gland and foot compared with the control group snails. The histological examinations of the digestive tubules included destroyed and detached in the outer layer covering digestive tubules. In addition, marked increase in the width most of the digestive tubules lumen. The intertubular connective tissue between the digestive tubules showed great destruction, while the foot of treated snails showed rupture of the epithelium covering the foot and desquamation of the epithelium. We also observed the presence of areas of connective tissue necrosis and destruction of the muscular tissue.ConclusionsIt has been found that extracts of Jatropha seeds have a toxic activity that caused histopathological damage that led to the death of land snails, and thus it can be recommended as a source for the development of molluscicides.Graphical

Sustainability assessment of coffee production in Brazil.

This paper aims to assess the sustainability of coffee production in Brazil by a framework at the farm level. The framework developed comprises four dimensions of sustainability structured from the literature review. Primary data were collected from 20 coffee farms selected from the most producing communities in the Planalto de Vitória da Conquista locality, sited in Centro-Sul Baiano middle region at the Bahia state. The main environmental issues identified related to coffee farmers are inadequate management of water consumption, influenced by the lack of knowledge about irrigation techniques in some cases, and the use of synthetic fertilizers and pesticides. The economic evaluation of the activity revealed a low index of producers belonging to a class organization. In social aspects the issues are low level of technical/technological instruction for coffee producers, temporary workers are often used, the old age of most producers, the lack of family succession for the activity, low incomes, the high number of temporary workers, and the absence of the worker gains. As for the technical dimension, only half of the farmers invest in innovation, which causes high obsolescence of their equipment and machinery and a low participation rate in training courses. In the environmental dimension, the farmers return the packages of pesticides to the stores where they bought them. In the technical dimension, most farmers perform soil analysis. Besides addressing the identified challenges, the initiatives can help achieve the Sustainable Development Goals, especially the 9th, 12th, and 13th.

The hunt for beneficial fungi for tomato crop improvement – Advantages and perspectives

Beneficial fungi with antagonistic and entomopathogenic properties have shown promising effect in the biological control of diseases and pests in a variety of commercially significant crops, including tomato, in recent years. Despite the fact that such treatments are environmentally safe, their risk on non-target species in tomato fields remains unknown. Beneficial fungi that have been commercialised for field use have had little effects on the population of arthropod pests and the incidence of diseases in tomato fields due to various reasons. The use of fungal antagonists and entomopathogenic fungi-based products for the management of diseases and pests of tomato crop has been done all over the world. The investigated reports, however, are scattered throughout the research papers, so they need to be compiled and discussed. Therefore, efficiency of antagonistic and entomopathogenic fungi against important pests and pathogens of tomato crop, as well as their practical use as biofungicides and bioinsecticides to reduce the use of synthetic pesticides, are discussed in this review paper. Besides, plant growth promotion activity of beneficial fungi, their appropriateness as an alternative of synthetic pesticides, and future prospects are also discussed.

Interview with Dr Minshad Ansari, Founder and CEO of Bionema Ltd

Bionema is a leading UK biopesticide technology developer. We create chemical-free, pest management solutions for the horticulture, turf &amp; amenity, landscaping, and forestry sectors. We have more than 30 years' experience in research, development, and the commercialisation of biopesticides. The company was founded in 2012 by Dr Minshad Ansari, a former academic who had already worked at research institutions across India, Belgium, and the UK. He joined Swansea University in 2005 and started working on the development of biopesticides for the control of insect pests in the horticulture and forestry sectors. When he visited growers and farmers, he was often asked about pest control methods that did not require the extensive use of chemical solutions. These queries made him investigate the development of non-toxic, natural methods of pest control that would reduce the need for chemical use. Once Dr Ansari developed his thinking around biopesticide alternatives, he set up Bionema in 2012 a spinout from Swansea University. The focus of Bionema's research was the development and commercialisation of naturally occurring microorganisms for crop protection against pests and diseases thereby reducing the use of synthetic pesticides, enhancing food security, and increasing crop yields. The company established its headquarters at the Institute of Life Science at Swansea University in the UK. In 2017, Bionema made a breakthrough discovery in the development of NemaTrident, a tri-component patented solution, and the conception of the microencapsulation formulation delivery system in 2018 for foliar challenges. Shortly afterwards, Dr Ansari raised £680,000 equity investment and received £1.1 million in grant funding from Innovate UK and the Welsh Government which was used for the development and commercialisation of UniSporeG, a unique fungal bioinsecticide for weevil control in soft fruits. Innovation in biopesticide formulations is a core objective for Bionema, enabling the company to commercialise multiple product lines and to generate a pipeline of advanced and early-stage products that include beneficial nematicides, bioinsecticides, compatible surfactants and delivery platforms. Bionema has also developed a robust patent portfolio and collected a library of more than a hundred commercially viable microorganisms for pipeline candidates.

Institutional and policy bottlenecks to IPM.

This paper summarises institutional and policy bottlenecks to IPM in Africa. Agricultural policy in Africa generally prioritises production and productivity above environmental sustainability, so the use of synthetic pesticides for controlling pests is encouraged. Funding for research in IPM is limited, and extension systems struggle to provide the level of farmer support that adoption of IPM often needs. Improved research and extension policies could facilitate uptake of IPM. Public and private food-safety standards can incentivise adoption, but currently this is mainly in production for export. Pesticide and other input regulatory systems unintentionally constrain adoption of IPM, through expensive registration procedures, weak compliance monitoring and limited regional harmonisation. IPM must be seen as a key element of food-systemtransformation.

Overview on Recent Developments in the Design, Application, and Impacts of Nanofertilizers in Agriculture

Nutrient management is always a great concern for better crop production. The optimized use of nutrients plays a key role in sustainable crop production, which is a major global challenge as it depends mainly on synthetic fertilizers. A novel fertilizer approach is required that can boost agricultural system production while being more ecologically friendly than synthetic fertilizers. As nanotechnology has left no field untouched, including agriculture, by its scientific innovations. The use of nanofertilizers in agriculture is in the early stage of development, but they appear to have significant potential in different ways, such as increased nutrient-use efficiency, the slow release of nutrients to prevent nutrient loss, targeted delivery, improved abiotic stress tolerance, etc. This review summarizes the current knowledge on various developments in the design and formulation of nanoparticles used as nanofertilizers, their types, their mode of application, and their potential impacts on agricultural crops. The main emphasis is given on the potential benefits of nanofertilizers, and we highlight the current limitations and future challenges related to the wide-scale application before field applications. In particular, the unprecedent release of these nanomaterials into the environment may jeopardize human health and the ecosystem. As the green revolution has occurred, the production of food grains has increased at the cost of the disproportionate use of synthetic fertilizers and pesticides, which have severely damaged our ecosystem. We need to make sure that the use of these nanofertilizers reduces environmental damage, rather than increasing it. Therefore, future studies should also check the environmental risks associated with these nanofertilizers, if there are any; moreover, it should focus on green manufactured and biosynthesized nanofertilizers, as well as their safety, bioavailability, and toxicity issues, to safeguard their application for sustainable agriculture environments.

The bacterial world inside the plant

Sustainable agriculture requires the recruitment of bacterial agents to reduce the demand for mineral fertilizers and pesticides such as bacterial endophytes. Bacterial endophytes represent a potential alternative to the widespread use of synthetic fertilizers and pesticides in conventional agriculture practices. Endophytes are formed by complex microbial communities and microorganisms that colonize the plant interior for at least part of their life. Their functions range from mutualism to pathogenicity. Bacterial endophytes colonize plant tissues, and their composition and diversity depend on many factors, including the plant organ, physiological conditions, plant growth stage, and environmental conditions. The presence of endophytes influences several vital activities of the host plant. They can promote plant growth, elicit a defense response against pathogen attack, and lessen abiotic stress. Despite their potential, especially with regard to crop production and environmental sustainability, research remains sparse. This review provides an overview of the current research, including the concept of endophytes, endophytes in plant organs, endophyte colonization, nutrient efficiency use, endophytes and crop nutrition, inoculation with synergistic bacteria, the effect of inoculum concentration on plant root microbiota and synthetic communities. It also examines the practical opportunities and challenges when utilizing endophytes in the field of sustainable agriculture. Finally, it explores the importance of these associations with regard to the future of agriculture and the environment.

Three strategies of transgenic manipulation for crop improvement.

Heterologous expression of exogenous genes, overexpression of endogenous genes, and suppressed expression of undesirable genes are the three strategies of transgenic manipulation for crop improvement. Up to 2020, most (227) of the singular transgenic events (265) of crops approved for commercial release worldwide have been developed by the first strategy. Thirty-eight of them have been transformed by synthetic sequences transcribing antisense or double-stranded RNAs and three by mutated copies for suppressed expression of undesirable genes (the third strategy). By the first and the third strategies, hundreds of transgenic events and thousands of varieties with significant improvement of resistance to herbicides and pesticides, as well as nutritional quality, have been developed and approved for commercial release. Their application has significantly decreased the use of synthetic pesticides and the cost of crop production and increased the yield of crops and the benefits to farmers. However, almost all the events overexpressing endogenous genes remain at the testing stage, except one for fertility restoration and another for pyramiding herbicide tolerance. The novel functions conferred by the heterologously expressing exogenous genes under the control of constitutive promoters are usually absent in the recipient crops themselves or perform in different pathways. However, the endogenous proteins encoded by the overexpressing endogenous genes are regulated in complex networks with functionally redundant and replaceable pathways and are difficult to confer the desirable phenotypes significantly. It is concluded that heterologous expression of exogenous genes and suppressed expression by RNA interference and clustered regularly interspaced short palindromic repeats-cas (CRISPR/Cas) of undesirable genes are superior to the overexpression of endogenous genes for transgenic improvement of crops.

Effectiveness of Neem Seed Extract Formulation (Azadirachta Indica) and Bitung (Barringtonia asiatica) against Mealybug Papaya (Paracoccus marginatus) (Hemiptera: Pseudococcidae)

The papaya mealybug (Paracoccus marginatus) Williams &amp; Granara de Wilink (Hemiptera: Pseudococcidae) is a main pest of papaya plants. Attacks by these pests can cause plants failed to produce the fruit and even to death. The usual control technique used by farmers is the use of synthetic pesticides that have a negative impact on human health and the environment. The alternative to control using botanical insecticides is a good solution to control the population of P. marginatus. The purpose of this study is to know the effect of neem seed oil formulation and bitung to know which treatments with concentrations are most effective in reducing the population density of papaya mealybug pests. The experiment took place in Rejasari Village, Langensari Subdistrict, Banjar City, West Java, from March 2021 to July 2021. Experiment using the Randomized Block Design consisted of ten treatments with three replications. The results were obtained that a formulation of bitung 3% could suppress the densities of papaya mealybug ( P. marginatus) populations at 65%. The average weight of the resulting papaya contained a 3% formulation of bitung found at 9.8 kg/tree. botanical pesticides of bitung oil 3% can be used instead of synthetic pesticides to control the population of P.marginatus.

In vitro evaluation of aqueous leaf and peel extracts of Musa species for low-input management of fungal leaf spots of sweet potato (Ipomea batatas Linn.)

Sweet potatoes are important food staples in tropical sub-Saharan Africa. Orange flesh sweet potato (OFSP) varieties are especially important for combating vitamin A deficiencies and nutrition-induced blindness. Fungal leaf spots are one of the many challenges constraining its production in Umudike, Southeast, Nigeria. The aims of this experiment were to isolate the causal fungi of leaf spots of OFSP and to attempt their control using aqueous extracts of banana peels, plantain peels and plantain leaf in vitro. Mycotic agents isolated from infected plant were Verticillium longisporum, Rhizoctonia solani, Penicillium chrysogenum and Aspergillus niger. Pathogenicity test conducted on the organisms revealed that the first three pecies were actively pathogenic, with infected sweet potato showing irregular brown spots/blights surrounded by chlorotic hallo around leaf veins and margins of the laminae; while A. niger showed weak infection of the plant. In the laboratory, four concentrations (10%, 25%, 50% and 75%) of ripe and unripe plantain peels, ripe and unripe banana peels, and senescent and new plantain leaves, griseovid® (a standard antifungal) and control (sterile water) were evaluated in vitro for inhibition of mycelial elongation of the test myco-pathogens associated with the leaf spot disease of the crop. The experiment was laid out as 3 x 4 x 8 factorial in CRD with 3 replications. The botanicals significantly (P≤0.05) and differentially retarded radial growth of the fungus over the control in a dose-dependent manner. However, the fungitoxicity of the botanicals were inferior but compared favourably with the standard antifungal griseofulvin (griseovid®). Exploiting the potency of these readily available, cost effective and eco-friendly agro-wastes against these fungal pathogens causing leaf blight of sweet potato will not only reduce the hazards and pollution challenges associated with use of synthetic pesticides but also increase food production in developing countries where synthetic fungicides are expensive and out of reach of low-input farmers.

Relationship between the Antifungal Activity of Chitosan-Capsaicin Nanoparticles and the Oxidative Stress Response on Aspergillus parasiticus.

The fungus Aspergillus parasiticus is a contaminant in agricultural crops and its eradication involves the indiscriminate use of harmful synthetic pesticides. In the search for antifungal agents of natural origin, chitosan (Q) and capsaicin (C) are coupled in the form of nanoparticles (Np), which can possess a direct application under specific conditions. Due to their small size, Np can cross through the cell wall, taking the cells into a pro-oxidant environment known as “oxidative stress”, which presents when the reactive oxygen species (ROS) surpass the number of antioxidants in the cell. In the present investigation, nanoparticles of chitosan (Np Q) and nanoparticles of chitosan-capsaicin (Np QC) with an average diameter of 44.8 ± 20.6 nm and 111.1 ± 14.1 nm, respectively, were synthesized, and there was a zeta potential of + 25.6 ± 0.7 mV and + 26.8 ± 6.1 mV, respectively. The effect of the concentration of Np Q (A, B, C, and D), of Np QC (A, B, C, and D), and capsaicin in a solution (control) was evaluated on the viability of the spores, the accumulation of intracellular ROS, and the morphometric changes of A. parasiticus. Acute toxicity of the Np was determined utilizing bioassays with Artemia salina, and acute phytotoxicity was evaluated in lettuce seeds (Lactuca sativa). According to ROS results, capsaicin (control) did not induce oxidative stress in the cell; otherwise, it was observed to have an elevated (p < 0.05) accumulation of ROS when the concentration of Np Q increased. For both, Np Q and Np QC, an inverse physiological pattern relating spore viability and ROS accumulation in the fungus was found; the viability of spores decreased as the ROS accumulation increased. The spore viability of A. parasiticus diminished upon increasing the concentration of chitosan (0.3–0.4 mg/mL) in the Np, while the intracellular accumulation of ROS increased proportionally to the concentration of the nanomaterials in the treatments of Np Q and Np QC. On the other hand, Np QC presented a lower (p < 0.05) toxicological effect in comparison with Np Q, which indicates that the incorporation of bioactive compounds, such as capsaicin, into nanoparticles of chitosan is a strategy that permits the reduction of the toxicity associated with nanostructured materials.

Assessment of the Larvicidal Potency of Bacillus thuringiensis Against the Moth of Spoladea recurvalis on Amaranths Plant

The control of Spoladeare curvalis, a major pest of amaranth plant, has been through the use of synthetic pesticides which have been reported to have detrimental effects. This study was aimed at assessing the larvicidal potency of B. thuringiensis against the larvae of Spoladea recurvalis on amaranth plant. The assessment of the larvicidal potency of B. thuringiensis isolates from cow range land and refuse dump sites in Zaria metropolis habouringCry1 gene (CR2, CR4, RD1) was carried out by spraying spore crystal mixture of B. thuringiensis isolates on amaranth plants infested with Spoladea recurvalis larvae. The mortality of S. recurvalis larvae, under a screen house were assessed after 24, 48 and 72hours of exposure to the spore crystal mixture of B. thuringiensis isolates. Spore crystal mixtures of B. thuringiensis isolates were effective in causing larvae mortality with more than 60% mean mortality rate of S. recurvalis larvae after 72hours of exposure. The mortality rate of Spoladea rescurvalis increased with increase in exposure period. Spore crystal mixture of Bacillus thuringiensis isolates should be considered as an alternative to synthetic pesticides for the control of Spoladea recurvalis larvae on amaranth plant. Keywords: Bacillus thuringiensis; spore; larvae; amaranth; larvicidal.

Effectiveness of Plants Extracts and Mycoinsecticide on Management of Cowpea Flower Thrips Megalurothrips sjostedti (Thysanoptera: Thripidea) under Field Conditions

To promote the use of natural substances for better management of the cowpea thrips Megalurothrips sjostedti, the potential of aqueous extract of Azadirachta indica, Boswellia dalzielii and Metarhizium anisopliae, alone and their combinations in comparison with the synthetic chemical insecticide (Decis) were tested. The experiments were carried out in two cowpea varieties under field conditions within the Sudano-Sahelian agro-ecological zone of Cameroon. Trials were arranged in a completely randomized block design with nine treatments. The nine treatments consisted of a negative control, A. indica; B. dalzielii; M. anisopliae, A. indica+B. dalzielii; M. anisopliae+B. dalzielii; M. anisopliae+A. indica; M. anisopliae+A. indica+B. dalzielii and Decis. Each treatment replicated four times. Vigna unguiculata plants were sprayed from flowering stage thrice with insecticidal products at 5 day intervals. The density of adults and larvae thrips was assessed on 5 flowers per block during 5 days after the last spraying of treatments. Results showed that, there were more thrips on Bafia variety than B125 variety (p&lt;0.0001). All the tested treatment significantly (p&lt;0.0001) reduced the cowpea flower thrips of 30% for A. indica, B. dalzielii and A. indica+B. dalzielii, 75% for M. anisopliae and its various combinations, and of 90% for Decis. Plants extracts, mycoinsecticide and their combinations considerably reduced damage induced by thrips compared to the negative control. A. indica, B. dalzielii, M. anisopliae and their combinations showed ability as natural traitement for the management of thrips in V. unguiculata. These products do not only protect V. unguiculata crop from its major pest, but also preserve the environment from harmful effects induced by the use of synthetic commercial pesticides.

Performance of cauliflower cultivars under different phytosanitary management in summer/autumn crops, under no-till in Santa Catarina

The performance of five cauliflower cultivars in conventional and alternative phytosanitary management—without the use of synthetic pesticides—was evaluated. Two experiments were conducted at Epagri, Ituporanga Experimental Station in February 2018 and 2019. A randomized block design with four repetitions was adopted, with twenty plants of each cultivar as plots. The seedlings were transplanted on millet and mucuna straw at a spacing of 0.5 m × 0.8 m. We evaluated agronomic yield, inflorescence quality, pest damage and plant diseases, especially bacterial and fungal rots. The cauliflower hybrids Vera, Verona and Serena stood out in productivity and quality, being the most indicated for sowing in off-season crops, in the Alto Vale do Itajaí region. The most productive cultivars were less damaged by bacterial diseases and defoliating caterpillars and without interference of whitefly infestation on yield. The results also reveal that it is possible to control pests and diseases with phytosanitary products of lower toxicity, i.e., with lower residues of synthetic pesticides.