Frateuria defendens reduces yellows disease symptoms in grapevine under field conditions

Life table studies are essential tools for understanding population dynamics. The life table parameters of Aphis gossypii Glover (Hemiptera: Aphididae) feeding on the host plant, Hibiscus syriacus L. were studied under laboratory (25±1°C and relative humidity of 65±5% and a photoperiod of 16L : 8D h) and field conditions (23-43°C, and relative humidity of 27-95%). The data were analysed using the age-stage, two-sex life table theory. The life table studies were started with 50 and 40 nymphs in laboratory and field conditions, respectively. Under laboratory conditions, A. gossypii reared on H. syriacus had a higher survival rate, fecundity, and longevity than those reared under field conditions. When reared under field conditions, A. gossypii had a longer nymphal developmental time, shorter adult longevity, and lower fecundity than those reared under laboratory conditions. The intrinsic rate of increase (r), net reproductive rate (R0), and the finite rate of increase (λ) under laboratory conditions, were higher than those obtained under field conditions. Nevertheless, there were no significant differences in the mean generation time T (days) between field and laboratory conditions. In the present study, the results clearly showed that life table parameters of A. gossypii were significantly different under field and laboratory conditions. These results could help us to understand the A. gossypii population dynamics under field conditions. The results could also help us make better management decisions for economically important crops

Toxic effects of glyphosate-based herbicide, Excel Mera 71 on gill, liver, and kidney of Heteropneustes fossilis under laboratory and field conditions

This study aims to evaluate the insecticidal activity of four bacterial strains against M. cerasi under both laboratory and field conditions, in order to provide a more sustainable and eco-friendly alternative to chemical insecticides. Four environmentally friendly bacterial strains were evaluated for their potential as biocontrol agents: Brevibacillus brevis (FD-1), Bacillus cereus (FD-63), Bacillus thuringiensis subsp. kenyae (FDP-8), and Bacillus thuringiensis subsp. kurstaki (FDP-41). Experiments were conducted under both controlled laboratory and field conditions. Data showed that mortality rates ranged from 33.33% to 93.33% under controlled conditions and from 13.33% to 50% under field conditions over the 96 h period. B. thuringiensis subsp. kurstaki (FDP-41) and B. thuringiensis subsp. kenyae (FDP-8) were the most effective bacterial strains against the aphids in controlled conditions. The percentage of mortality related to these applications was 93.33% and 80% in 96 h under laboratory conditions. However, the effectiveness of B. thuringiensis subsp. kurstaki (FDP-41) was 50% at 96 h in the field. These findings suggest that B. thuringiensis subsp. kurstaki and B. thuringiensis subsp. kenyae hold significant potential as biological control agents against M. cerasi. Additionally, FDP-41 showed the lowest LT50 value of 25.37 h in the laboratory and 86.40 h in the field. This indicates a much more rapid and potent effect on M. cerasi compared to other strains. As a result, it was concluded that these bacterial strains may be used successfully as biocontrol agents in the biological control of M. cerasi. Their successful use could reduce reliance on synthetic insecticides, thereby minimizing pesticide residues on crops and contributing to safer agricultural production and environmental sustainability.

Conventional tillage and planting method for rice (Oryza sativa L.) production in northern Iran is wet tillage (puddling). Effect of different puddling intensities on physical properties of a silty clay soil (Typic Haplodalfs) was investigated under laboratory and field conditions. Changes in soil physical parameters and water requirement for puddling were measured. For laboratory experiments, undisturbed cylindrical soil samples (diameter and height of 50 cm), were used. A laboratory puddling apparatus was designed and constructed. The puddling intensity was measured by duration of puddling. Four levels of puddling intensity were used as: P0 (no puddling, control), P1 (low), P2 (medium) and P3 (high). For field tests, 12 plots of 8 × 4 m were selected. The first tillage was performed with a moldboard plow and then the plots were puddled with different intensity using a rotary tiller. The results showed that under laboratory conditions, water content of the puddled layers decreased with an increase in settling time. During drying period, P0 dried faster than P1, P2 and P3. Puddling with low intensity in laboratory and field conditions caused bulk density of 0–15 cm soil layer to decrease by 24.07 and 25.45%, respectively. Increasing puddling intensity increased the bulk density. Bulk density increased with time as particles settled after halting the puddling. Bulk density increased with depth as well. Under laboratory conditions, increasing puddling intensity from P1 to P2 reduced percolation rate significantly. For all puddling intensities, soil moisture characteristic curves of both field and laboratory samples showed that puddling increased the amount of water retained over the whole range of suctions. More water was needed for P3 as compared to P1 and P2. Under the laboratory and field conditions, the P3 required 27.72 and 28.58% more water as compared to P2, respectively. Although the mechanisms implemented for puddling were different under laboratory and field experiments, the results were similar. Bulk density, soil moisture content and water percolation rate decreased faster in the puddled soil under field and laboratory conditions. Therefore, to reduce the cost and time, the laboratory method could be used to study the effects of puddling intensity on physical properties of paddy soils. Medium intensity puddling was shown to be the proper tillage practice for paddy fields with silty clay soil.

Efficacy of insecticides and biological control agents in an Integrated Pest Management (IPM) program requires a full understanding of both these factors and their interactions. With this in mind, a study was conducted to build an IPM strategy to control Myzus persicae (Homoptera: Aphididae) in field Mustard (Brassica compestris) crops using a combination of insecticides and biological control agents. Five different insecticides (methomyl, matrine, carbosulfan, thiamethoxam, and pymetrozine) were used to test the survival of Aphidius matricariae wasps under field and laboratory conditions. Under laboratory conditions five different concentrations (1%, 0.5%, 0.25%, 0.13% 0.06%) along with the control were made of each insecticide. Parasitoids exposed to Pymetrozine showed the highest percent emergence at 82.96%, 65.18%, 64.07%, 53.70% and 46.66% of from mummified aphids followed by thiamethoxam, carbosulfan, matrine and methomyl, whereas under field conditions none of these insecticides showed negative impacts on the emergence of A. matricariae wasps. In the presence of insecticides, no significant effect on emergence of A .matricariae wasps from mummified aphids was observed with pymetrozine showing 90.91% emergence of A. matricariae wasps, carbosulfan 81.25%, matrine 80.27%, thiamethoxam 77.29% and methomyl 75.49% emergence, respectively. In addition to observing the effect of insecticides on the emergence of A. matricariae, efficacy of these insecticides against populations of M. persicae was also studied. In order of efficacy, thiamethoxam > matrine > pymetrozine > carbosulfan > methomyl showing 91.37%, 89.61%, 72.46%, 56.6% and 54.35% reductions in aphid populations, respectively. The results of this study show that a biological control agent together with these insecticides can be used simultaneously as part of an IPM program to control M. persicae in field Mustard.

Diaphorina citri Kuwayama is considered the most important pest of citrus since it transmits the bacterium Candidatus Liberibacter spp., causing the death of millions of citrus trees all over the world. This research studied the ability of Ceraeochrysa valida (Banks) as a biological control agent against D. citri. The study was conducted under field and laboratory conditions, considering four different criteria: 1) distribution and presence of C. valida in lemon orchards in the state of Colima, 2) maximum predation of C. valida on D. citri nymphs under laboratory conditions, 3) life tables of D. citri with release of C. valida under field conditions, and 4) predation of C. valida on D. citri in the field. The results showed that Ceraeochrysa valida was present in the orchards evaluated throughout the year. The average amount of D. citri nymphs consumed by C. valida under laboratory condition was 258.26 ± 3.80. The release of 20 larvae of C. valida in the field produced an average mortality of 160.29 ± 26.32 nymphs of D. citri against 27.33 ± 3.39 without release (F = 11.98, Pr > F = 0.0134). The analysis of life tables for the months of December, January, February and March showed that egg and nymph mortality was higher in treatments in which C. valida was released (0.9768; 0.8482; 1; 0.9922) compared to those in which no release occurred (0.8481; 0.4467; 1; 0.8032). Ro reached values lower than one under release treatments (0.1628; 0.5893; 0.000; 0.4870), while these were close to or higher than one (0.7278; 1.1733; 0.1231; 1.0787) in the treatments without release. It can be concluded that C. valid can be considered as a biological control agent against D. citri.

Grey and blue mould diseases are among the most important diseases of grapes worldwide. They are causing extensive decay in postharvest grapes. Chemical fungicides remain the primary treatment for managing these diseases. However, consumer’s interest in organic produce, restrictions on chemical use by some countries, and concerns about human and environmental safety have driven research to identify safe and effective alternatives. Among several alternative approaches, the use of biological control agents (BCAs) is getting more acceptance and has been comprehensively studied. This review summarizes the use of BCAs as a postharvest treatment to control the postharvest grey and blue mould of grapes. The review also emphasizes the economic importance of these two major postharvest diseases of grapes. In addition, other non-chemical postharvest treatments, the advantage of an integrated approach and finally problems, challenges, and future trends of the BCAs are described. Several yeasts that have a promising result to control grey and blue mould disease of grapes are thoroughly reviewed. The current market share of BCAs and their future directions on commercialization are also suggested in this review. Biocontrols can be a potential control method for postharvest diseases of fruits and vegetables in place of chemical fungicides. Antagonistic yeasts have high ability to suppress fungal growth. Integrated approach utilizes a combination approaches, which often results in a synergistic effect to control the diseases. USA and Europe are currently the largest markets for biocontrol products.

Currently there is very little information on the response of fruiting perennial plants to applied P. This is especially true for tropical production areas where soils have a high capacity of P fixation, and are poor in native phosphorus. An alternative to soil P fertilization, which is inefficient in fixing soils, is to apply phosphorus as a foliar spray. P is quickly absorbed by leaves, and is redistributed quite well through the plants because its phloem mobility, and foliar application may be a viable practice. The purpose of this present work, is to determine the effectiveness of foliar P application on the nutritional status and yield of guava. The experiment was done in a Typic Hapludox, for three consecutive agricultural years, in an adult orchard of ‘Paluma’ guava. Five treatments were tested: four rates leaf applications of P (0 0.5 1.0 and 2.0% of P2O5) and a control where P was applied to soil (200 g of P2O5/plant). Through the results it was verified that the foliar application of P altered the concentration of the nutrient in the soil (13 to 48 mg dm P-resin), and in the guava leaves (1.2 to 1.8 g of P kg), but did not affect the production of fruits. In conclusion, in field conditions, it is viable to combine the phosphorus foliar fertilization with disease control, without increasing the operations and, consequently, the production cost. INTRODUCTION Brazil contains large areas with a climate and soil favorable to the production of fruit trees. Phosphorus is a significant concern in Brazilian agriculture. The development of fruit trees after plantation is favored by a supply of P through the soil, which stimulates the growth of roots and, as a reflex, the development of the aerial part (Marschner, 1995). The relative demand for phosphorus decreases with the age of trees (Malavolta, 1979). Although the application of phosphated fertilizer in perennial cultures is not widely used, there is sufficient evidence to demonstrate that the application of the element may increase production. One of the most difficult aspects in the study of perennial plant nutrition is the large masking role internal nutrient circulation may have on the short term response of crops to the application of fertilizers. Although this phenomenon happens with all the mobile nutrients in the phloem (Marschner, 1995) this may be more important when there is a natural shortage of element in the soil, as in the case of phosphorus. In experiments conducted in field over three consecutive years, in different soils and with different cultivars, Natale (1993) did not obtain any response when he applied increasing doses of phosphated fertilizer to the soil in developing guava tree orchards. The absence of a response to conventional fertilization in the soil induced the development of a new experimentation using P, which confirmed the capacity of the guava tree to absorb and redistribute the element from the application of fertilizer on the leaves (Natale et al., 1999). The aim of fertilizer application to the leaves is to provide trees with the elements which must be assimilated immediately (to correct some deficiency for example) or those which may encounter problems in the soil, as in the case of phosphorus (Gautier, 1993). Malavolta (1980) reports that, according to the culture and conditions of the soil maintainance, foliar fertilization may provide the required elements in small proportions (g.ha) exclusively through the leaves. In the specific case of the guava tree, Natale (1993) observed that the phosphorus export for Proc. IS on Foliar Nutrition Eds. M.Tagliavini et al. Acta Hort. 594, ISHS 2002 172 production of 1 ton of fresh fruits was of just 121 grams of P. According to Alexander (1986) in cultures which receive regular pesticide spraying, foliar application of nutrients is increasingly important. Although foliar fertilization with macronutrients may not be a recommended technique, there are some situations when application of foliar fertilizer, incombination with pesticides, may be used without any extra application cost. Very few publications in the literature may be found on the effects of foliar applications on guava trees (Arora & Singh, 1970; Singh & Rajput, 1977; Thanaa et al., 1994). Once P has been rapidly absorbed by the leaves, it is redistributed in the plants hence the foliar application of the element may be effective technically as well as economically. MATERIAL AND METHODS The experiment has been developed in a guava tree orchard, upon a Typic Hapludox, located in the district of Sao Carlos, in the state of Sao Paulo, in Brazil. The geographical situation of the site is 22°15' latitude South, 47°54’ longitude West, altitude 810 m. The chemical analysis of the 0-20 cm soil layer in the lines, before installing the experiment, revealed: pH (CaCl2) 4.0; organic matter 30 g dm; P (resin) 19 mg dm; K, Ca, Mg and H + Al, 2.3 5 3 88 mmolc dm, respectivily. The orchard contained five year old guava from cuttings (Psidium guajava) ‘Paluma’. The test was carried out during three consecutive agricultural years, from 1994. Random blocks were chosen for the experiment with five treatments and four repetitions. The doses of phosphorus (MAP-monoammonium phosphate) treatment were the following ones: zero 0.5 1.0 2.0% of P2O5 (foliar method) and at the fifth treatment 200 g of P2O5 per plant, with a single application through the soil. The experimental plots consisted of four trees at 7m x 5m spacing, the first four plants represented the border. All the trees received constant doses of nitrogen, potassium and liming. Doses of N and K were parceled in four times and were applied at the same times as the phosphorus foliar fertilizations. According to the objective of this study, the foliar application combined phosphorus with pesticides typically used in the culture of Guava. The evaluation of the nutritional state of the plants was made by means of yearly foliar samplings, according to recommendation of Natale et al. (1994). Soil was analysed annually to determine fertility in soil samples removed at the end of the production period. The effect of treatments on the guava tree production was estimated by weighing all the fruit of the effective surface of each plot. RESULTS AND DISCUSSION The chemical characteristics of the 0 20cm layer of the Oxisol, in the three years of the test, underwent small variations according to the treatments, but without any statistical difference. With relationship to the phosphorus it is observed that, except for the year 1994/95, there was statistical difference among the application in the soil and the foliar application, with the first presenting, average, higher values of P (Table 1). During the three years of the experiment, the concentration of phosphorus in the soil was in all the treatments in the range considered average for the perennial crops by Raij et al. (1996). With the increase of the P dose, there was a linear increase of phosphorus in the soil (Fig.1). The normal winter fall of leaves (and the consequent mineralization) as well as some dripping of the solution which was applied on the plants, or some washing of the macronutrient, from the leaves during the rain period, may explain these results. Boaretto and Muraoka (1995) report that in general, when foliar spraying is used, approximately 40% of the applied solution falls on the soil and the nutrients with it. The chemical analysis of the space between tree rows revealed phosphorus values between 7 and 10 mg dm, in the three years of the experiment, which confirms that the area of soil under the plants which received foliar fertilization was enriched. When we compare the concentration of P comprise between 8-18 mg dm, ideal according to Koen and Hobbs (1990) for the conditions of soil of South African orchards, we may consider that in this study those values were observed with the smallest dose of phosphorus application and even in the control treatment. Foliar

Long-term benefit contribution of chemical and biological nematicide in coffee nematode management in soil microbial diversity and crop yield perspectives

The research study was carried out under the cotton field conditions (kept free from insecticides) at SALU – Khairpur during, 2017. The data was taken on a weekly basis from randomly selected on 20 plants for pest population and it’s proper biological control from seedling up to the harvest of the crop. The population of jassid was recorded from different parts of the plant (top, middle, and bottom portions). Thus, the biological control of jassid pest was confirmed under laboratory conditions with its proper emergence and percent population was also evaluated. Further, the results showed that the maximum population of jassid population was recorded in the month of August on top portion 4.34±0.87 and minimum in September on bottom portion 0.78±0.71 whereas; the biological control of jassid known as jassid endo-parasite, Arescon enocki is first time reported from this region (upper Sindh) which was observed in the month of July 30% and in October 18% under laboratory conditions at Department of Zoology, SALU – Khairpur. It was concluded that the population of A. biguttula biguttula was found fluctuated under field conditions and its proper biological control throughout the season. It is further recommended to encourage the biological control, A. enocki that may cause to get rid of from the vigorous jassid pest of the major cultivated cotton crop at the upper region of Sindh province.

Leaf rust of wheat (Triticum aestivum L.), incited by Puccinia recondita ex Desm. f. sp. tritici Eriks, is one of the most important wheat diseases in Egypt. Methyl jasmonate (MJ) is a potential plant elicitor which induces a wide range of chemical and anatomical defense reactions in conifers and might be used to increase systemic resistance against biotic damage. In the greenhouse, different concentrations of MJ (10, 20 and 30 mM) were applied as seed soaking plus foliar spray or only as foliar spray to control leaf rust and induction of secondary compound production in leaves of wheat plants. Foliar spray was applied after 30 and 50 days of sowing. Results indicated that all concentrations and treatments reduced the severity of rust disease caused by P. recondita f. sp. tritici in wheat leaves during 45 days of inoculations. Disease incidence was decreased significantly in MJ-treated plants as seed soaking plus foliar spray with 20 and 30 mM when compared to 10 mM MJ or control plants. The study revealed that, with increasing concentrations of MJ, the secondary metabolites were greatly increased. Endogenous levels of both free and conjugated putrescine, spermidine and spermine increased in response to the elicitor. Activities of polyamine biosynthetic enzymes of ornithine decarboxylase (ODC) and polyamine oxidase (PAO) displayed up to threefold increases relative to untreated control. Moreover, significant increases in activities of plant defense-related protein, enzymes as peroxidase and chitinase as well as free and conjugated phenols contents were recorded in treated plants compared with untreated and infected plants. Furthermore, MJ treatment increased the chlorophyll-a, chlorophyll-b and carotenoids pigments contents, the higher increase was obtained with combined treatment between seeds soaking plus foliar spray at 20 and 30 mM of MJ. Under field conditions, three concentrations of MJ, i.e. 10, 20 and 30 mM as combined treatment between seeds soaking plus foliar spray or only as foliar spray were applied to study their effect against rust disease. Foliar spray was applied after 30 and 80 days of sowing. Results showed that the high reduction in disease severity was obtained with combined treatments between seeds soaking plus foliar spray with MJ at 20 and 30 mM compared with other treatments and control. At the same time, all treatments increased the growth and grain yield of wheat plants. It could be suggested that combination treatment between seeds soaking plus foliar spray with methyl jasmonate might be used commercially for controlling rust disease of wheat plants under field conditions.

In this study, the effect of some antagonist bacterial strains was investigated for biological control of fire blight caused by Erwinia amylovora that causing serious loss of product and drying on pome trees, especially on pear trees, in laboratory and field conditions. As alternative the chemical control, 3 different antagonistic bacteria Pantoea agglomerans RK-79, Pantoea agglomerans RK-84 and Pseudomonas putida RK–142 strains were used against E. amylovora on detached pear flower in laboratory and pear shoots in field conditions. As the result of the experiments conducted on flowers bunch in laboratory condition, P. putida RK–142 P. agglomerans RK–84 and P. agglomerans RK–79 isolates reduced the disease severity by the rate of 57,2%, 48,9%, and 14,4% respectively. Experiments in field was conducted between 2010 and 2011 in orchard of Erzincan Horticultural Research Station. In the experiments conducted on exile of the plant in the field condition, it was observed that the effects of the biological control agents prevented the development of the disease, but this effect disappeared after a while, depending on the number of applications. It was observed that the protective applications to do with biological control agents against the fire blight had the effect of preventing the development of disease on shoot during the vegetation period.

Simple SummaryThe prickly pear Opuntia ficus-indica L. has an important economic role as a source of food for human consumption, for cosmetic and pharmaceutical purposes, and as fodder for livestock in Morocco. This crop is now attacked by a new sap-sucking insect pest, the wild-scale Dactylopius opuntiae (Cockerell). The aim of this study was to investigate the insecticidal potential of essential oils as alternative to synthetic insecticides for the control of D. opuntiae nymphs and adult females under laboratory and field conditions. Results revealed that Mentha pulegium and Origanum vulgare oils provided a rich source of bioactive compounds and exhibited high contact toxicity against D. opuntiae. In addition, M. pulegium and O. vulgaris oils applied in combination with black soap induced the highest toxic activity on adult females under field conditions.The carmine cochineal Dactylopius opuntiae (Cockerell) is the major insect pest of the prickly-pear cactus Opuntia ficus-indica (L.) in Morocco. The present study investigated the insecticidal activities of six essential oils (EOs) against nymphs and adult females of D. opuntiae applied singly or in combination with a detergent under laboratory and field conditions. Under laboratory conditions, M. pulegium and O. vulgare L. essential oils showed a high level of insecticidal activity at 5%, with 98% and 92% females’ mortality, respectively, 5 days after treatments. The M. pulegium and O. vulgaris oils at 5% applied in combination with black soap at (60 g/L) induced the highest toxic activity on adult females, 100% and 96% at 5 days after treatments, respectively. Under field conditions, M. pulegium and O. vulgare oils at 5% in combination with black soap (60 g/L) showed the highest adult female mortalities with 96.33 and 92.56%, respectively, 7 days after the first application. The double application of M. pulegium oil at 5% significantly increased the mortality of adult females up to 91%, 5 days after the second spray. GC-MS analysis revealed that the most abundant constituent of M. pulegium and O. vulgare oils was pulegone (84.69%) and durenol (76.53%), respectively. These findings showed that the use of M. pulegium and O. vulgare in combination with black soap or in double sprays could be incorporated in the management package for the control of the wild cochineal D. opuntiae, as a safe and natural alternative to chemical insecticides.

BackgroundThe root-knot nematode, Meloidogyne spp., are one of the most dominant and dangerous group of pests. The deformations and discolorations make tubers unmarketable and/or of less quality. Therefore, management of Meloidogyne spp. becomes an obligatory challenge that warrants intervention. Biological control agents are the best alternative tools for controlling plant-parasitic nematodes that comply with the requirements of the development of the green agriculture and that reduce the reliance on these harmful chemicals. Therefore, this study aimed to evaluate the effectiveness of compost singly, and in combinations with the bio-agents Heterorhabditis bacteriophora, and two bacterial isolates Nem 212 and Nem 213 against the root-knot nematode Meloidogyne incognita infecting potato plants under field conditions.ResultsAmong 15 bacterial isolates (Nem205-Nem219) obtained from the rhizosphere of tomato and eggplant from Giza, Egypt, the two isolates (Nem 212 and Nem 213) were molecularly characterized based on the partial 16S rDNA sequencing analysis. These two bacterial isolates were deposited in the GenBank as Bacillus cereus Nem 212 and B. cereus Nem 213 and were tested against M. incognita J2s in vitro. Results showed that the cell filtrates of B. cereus Nem 212 and B. cereus Nem 213 gave the highest percentage of M. incognita J2s mortality (100%), after 48 h of the in vitro application. Moreover, all the applied treatments significantly suppressed the reproductive of M. incognita on potato plants and enhanced the potato crop yield under the field conditions. Compost enriched with B. cereus Nem 212 cell suspension was the most effective treatment. The combination between the bacterial cell suspension and the compost offered an increase in the disease curing and the potato plant growth and yield production, compared to the treatment with compost alone. The entomopathogenic nematode, Heterorhabditis bacteriophora, was relatively less effective in controlling M. incognita on potato, compared to B. cereus Nem 212 and/or B. cereus Nem 213 treatments. However, when compost was enriched with H. bacteriophora, it increased its capability to control the nematodes.ConclusionsThis study provides insights into the practical usage of EPNs H. bacteriophora, and the endophytic bacteria (B. cereus Nem 212 or B. cereus Nem 213) as biocontrol agents against M. incognita on potato plants. The application of compost enriched with the bacterial cell suspensions of either B. cereus Nem 212 or B. cereus Nem 213 and H. bacteriophora within Galleria mellonella cadaver proved efficient control of M. incognita infecting potato plants and improved the growth and yield of potato plants under field conditions.

Context/Purpose: The urban ecosystem of Akanda behind the airport of the capital city of Libreville in Gabon, harbors diverse and dense mosquito larval habitats and hotspots for malaria and arboviruses transmission. To effectively conduct vector control, it is imperative to adopt an integrated approach by adding biolarvicides to the toolbox. The main objective of this study is to evaluate the efficacy of a biolarvicide under laboratory and field conditions. Methods: In Gabon, this current pilot and preliminary study sought to test the efficacy of the biolarvicide VectorBac® Water dispersable Granule (WG) (VBG) during the rainy season period (March to May 2024) under field and laboratory conditions following the 2005 World Health Organisation protocol. Results: For the bioassay of VBG, in the laboratory, the required dose to kill 88% and 100% of the larvae in rearing cups was 0.001 g/mL and 0.01 g/mL respectively. Under field conditions, the percentage larval density reduction irrespective of the microhabitat type ranged from 90 to 100% and the mosquito larval density reduction between test and control groups in the field differed statistically (X2=34; p = 0.026). Conclusion: The larvae from Akanda tested under field and laboratory conditions were very sensitive to the standard dose recommended by the manufacturer after 24 hrs post-treatment with VBG. This pilot study provides baseline information that is required to conduct a longitudinal study to evaluate the residual effect of VBG in different ecological settings in Gabon.