Abbott's Formula Research Articles

The article presents research materials on assessing the effect of crop treatment with a biopreparation based on the endophytic bacterium Bacillus mojavensis PS-17 and its mixtures with various humic biostimulants on the productivity, disease resistance, and grain quality of spring barley. Field studies were carried out on the territory of the experimental fields of Agrobiotechnopark of Kazan State Agrarian University in 2023-2024. The scheme of the stationary field experiment provided for the study of the following options: control (without spraying); spraying plants with Humate +7 at a dose of 0.5 l / ha; spraying plants with Bigus extra at a dose of 0.5 l/ha; spraying plants by PS-17 at a dose of 1 l/ha; spraying plants with a tank mixture of the preparations Gumat +7 at a dose of 0.5 l/ha and PS-17 at a dose of 1 l/ha; spraying plants with a tank mixture of the preparations Bigus Extra at a dose of 0.5 l/ha and PS-17 at a dose of 1 l/ha. The initial humus content was 4%, mobile phosphorus - 275 mg/kg of soil according to Kirsanov and exchangeable potassium - 185 mg/kg of soil according to Kirsanov, pH - 6.1 in the salt extract. The experiment was repeated three times, the plots were placed using the randomized repetition method, the area of the experimental plots was 25 m². The system of primary and pre-sowing soil preparation included stubble cultivation, plowing, cultivation, pre-sowing harrowing, and the application of azophoska at a rate of 150 kg/ha. The least development of net leaf spot was observed when using a biopreparation based on the endophytic bacterium B.m. PS-17 (biological efficiency - 28.6%, compared to the control). Minimal development of root rot was noted when using a mixture of the humic preparation Humate +7 with the biopreparation based on B.m. PS-17 (biological efficiency - 13.8%, compared to the control). Biological efficiency was determined by the Abbott formula based on average values for 2 years. The use of all plant treatment options stimulated the growth of the leaf surface area of plants. The maximum indicators (17.3 m2/ha) were in the option - Humate + 7 + PS-17. Double application of the biopreparation Bigus Extra ensured the maximum yield increase of 13.88%, but its positive effect was due to a more significant increase in yield in the dry year of 2023. In 2024, the yield for all experimental options with treatments was approximately at the same level.

Chorioptic mange is a challenging condition to treat due to the superficial locations of the nonhematophagous mite Chorioptes bovis, and while topical acaricides are recommended, the clinical feature relapses are frequent. In a double-blinded clinical trial, three randomized groups of Spanish-Breton horses (n = 32) naturally infected with C. bovis on their legs were evaluated over a period of 70 days. All treatments were applied once every 14 days for three treatments. Before treatment and on Day (D)10, D25, D37, D56, and D70, each leg per animal was scored according to equine pastern dermatitis clinical presentations and severity (1 = mild, 2 = exudative, and 3 = chronic proliferative), and mite reduction was calculated using a 2 cm × 6 cm adhesive tape counting total mites on D36, D56, and D70. The trial aimed to assess the clinical improvement and efficacy of a topical pyrethroid emulsion alone (Group 1), and in combination with benzoyl peroxide (Group 2), compared to a control group (Group 3). The trial also included environmental disinfection. The acaricide efficacy was determined using Abbott's formula. Our analysis reveals no adverse reactions attributable to the treatment, yet lesions showed limited clinical improvement. Both treatment groups exhibited mite reduction compared to the control. The mite reduction on the evaluated days was 14.58%, 47.62%, and 55.77% for Group 1 and 85.42%, 88.10%, and 78.85% for Group 2, respectively. The mite reduction was significant in Group 2 on D56 and D70 (p < 0.0156) compared to the pretreatment and superior to Group 1 (p < 0.0229) at the end of the study (D70). The age and mite numbers showed no significant connection. In horses with higher clinical scores, there were no significant changes, most probably due to the short length of the study. The combination of benzoyl peroxide with topical pyrethroids can reduce the numbers of C. bovis mites, and it can be considered an alternative therapeutic option in horses.

A utilização do manejo integrado de pragas, associado ao controle biológico, tem sido uma estratégia eficiente, econômica e mais sustentável no controle de agentes danosos à agricultura. A fase larval de Spodoptera frugiperda, umapraga agrícola presente em diversas culturas, é causadora de prejuízos financeiros para o agronegócio, e os entomopatógenos têm sido amplamente utilizados no controle biológico dessa espécie. Assim, o objetivo do trabalho foi avaliar a patogenicidade de bactérias e vírus no manejo de S. frugiperda, em condições de laboratório. Para os bioensaios, utilizamos seis tratamentos por cinco repetições contendo seis lagartas (com segundo e terceiro instares) em cada. Os entomopatógenos utilizados foram S. frugiperda Multiple nucleopolyhedrovirus (SfMNPV), Autographa californica multiple nucleopolyhedrovirus (AcMNPV), Bacillus subtilis, B. thuringiensis subsp. thoworthy, e B. thuringiensis subsp. kurstaki. A avaliação da mortalidade ocorreu diariamente até a finalização do ciclo larval. Para a avaliação da mortalidade, utilizou-se a análise de variância (teste F), comparada posteriormente ao teste Scott-Knott a 5% de probabilidade e à eficiência dos bioinseticidas através da fórmula de Abbott. De modo geral, os entomopatógenos mais eficientes foram SfMNPV e B. subtilis, obtendo 100% de mortalidade nas lagartas de segundo instar, enquanto para as de terceiro instar, o AcMNPV mostrou letalidade máxima em 76,67% das amostras.

The mango mealybug Rastrococcus invadens Williams causes enormous damage to fruit trees in Burkina Faso, with losses of up to 90% for mango trees and 53% for citrus fruits. The objective of this study was to evaluate the insecticidal effects of native plant extracts against this insect pest. The insecticidal activity and biological effectiveness of the extracts were evaluated on Petri dishes and mango leaves previously contaminated by spraying them with the native plant extracts. The experimental was a completely randomized Fischer block, and compared six doses of the hydroalcoholic extracts of A. conyzoides and H. suaveolens with abamectin 18 EC and water (control). These treatments were repeated up to ten times. The determination of the efficiency coefficients was achieved using Abbott's formula (1925). Both extracts of A. conyzoides and H. suaveolens were effective, but the one based on A. conyzoides at 50 gl -1 was the most effective with 100% mortality in 48 hours compared to 95.00% for H. suaveolens’ extract in 72 h. Their respective LC50 were 12.50 gl -1 and 17.49 gl -1, showing that A. conyzoides’ extract is more toxic to R. invadens. The high content in phenols, flavonoids, alkaloids, etc. of leafy stems of A. conyzoides and of H. suaveolens could help to sustainably control R. invadens in an integrated approach and effectively protect mango orchards.

There is a growing demand for natural products to be used to control fleas in pets. A prospective, double-blind, randomized, placebo-controlled study evaluated the efficacy of the biological plant-based food supplement Bioticks® (thyme, rosemary, lemon balm, fenugreek, wormwood, and lemongrass extracts) as a flea control product in naturally flea-infested cats with an indoor-outdoor lifestyle. Ten cats were used as placebo controls (group A). Ten other cats were fed the same daily diet but supplemented with Bioticks® (group B). Fleas were counted by combing at D0 and D0 + 14 days, then one, two, three, four, and five months after the start of this study. No flea treatment was administered, and no environmental changes were made for six months prior to the start and throughout this study. The product was well-tolerated. The mean flea population in group B progressively and steadily decreased to reach 3.3 ± 2.1 at month five. At the same time and under similar maintenance conditions, the average flea population in group A remained stable (14.3 ± 2.5) until the fifth month. The percentages of efficacy (Abbott formula) in group B compared to group A was 27%, 20%, 52%, 66%, and 77%, respectively, at one, two, three, four, and five months after the start of this study.

Immediate and long-term efficacy of Felpreva®, a new spot-on formulation containing tigolaner, emodepside and praziquantel, applied as a single application to cats artificially infested with the cat flea Ctenocephalides felis

Beauveria bassiana is an entomopathogenic fungus that causes the white muscadine disease in insects. The majority of entomopathogenic fungi are soil and insect borne, 15 soil samples were collected from seven different locations during 2021, from January to December. Similarly, during 2022, March to December, 15 fungus-infected insect specimens were collected from five different locations hence soil and insect samples from various ecosystems were collected. As a result, 30 B. bassiana isolates from 11 different geographical areas were identified using morphological characteristics and multilocus sequence data in this investigation. The taxonomical positions of the isolates were determined using morphological characteristics and phylogenetic inferences based on three loci (Internal Transcribed Sequence, Elongation Factor-1α, and B. bassiana chitinase 1). In phylogenetic analysis of B. bassiana, the Maximum Likelihood analytical method produced distinct tree topology when compared to Neighbor-joining and minimum evolution. Three isolates viz., Bb3, Bb7 and Bb20 were found closely linked with reference isolate (KTU-24) and other showed the higher population diversity among them. The genetic distances of 30 B. bassiana isolates revealed that 15 were not closely related (D varied from 0.003 to 0.036). The pathogenicity of B. bassiana isolates from various hosts along with one commercial formulation (Beveroz) was assessed against Tetranychus truncatus under in vitro conditions by a completely randomized design (CRD) experiment. The same experiment was repeated thrice to confirm the pathogenicity of B. bassiana against T. truncatus. Later, the collected T. truncatus mortality data was converted into corrected mortality by using the Abbott formula and the values were examined using analysis of variance (ANOVA) in SPSS 23.0 software. Duncan’s Multiple Comparison Test was also done to compare the percentage mortality rates among the 30 B. bassiana isolates. The recorded results showed that the Bb6, Bb15 and Bb12 isolates caused significantly higher mortality of T. truncatus, i.e., 97.73, 96.73 and 94.50% respectively, than the other isolates. This study showed the relativeness among the B. bassiana isolates and establishes their bio-efficacy against T. truncatus, which further can be used for commercialization as bio-pesticide.

In this study, Tea Tree Oil, (Timorex Gold), Orange Oil (Prev-Am), Reynoutria spp. extract (Regalia), Bacillus subtilis QST 713 (Serenade SC), Lactobacillus acidophilus, Lactobacillus paracasei (Vitanal) and a reference product Fluopyram+Tebuconazole (Luna Experience) were applied to pepper plants to determine the efficacy against powdery mildew disease caused by Leveillula taurica (Lev.) Arm on pepper. The disease on plants was evaluated based on the 0-5 scale when the disease reached to 20% on untreated plots. Trials were established as a randomized plot design with four replications. The disease severity was assessed using Towsend-Heuberger’s formula and the percentage effect of the applications was calculated using the Abbott formula. The conducted experiments were revealed that the highest % efficacy values of the preparations against powdery mildew were obtained from Timorex Gold (80%), Prev-Am (45%), Regalia (44.7%), Serenade (26.3%) and Vitanal (26.2%), respectively. The efficacy of the reference product, Luna Experience, against powdery mildew in pepper was found 89%. It has been concluded that Timorex Gold preparation performed enough efficacy against Leveillula taurica, and can be safely used and offered against powdery mildew.

Control of Curculio caryae (Coleoptera: Curculionidae) with Reduced Rates of a Microbial Biopesticide

Objective: To test the efficiency of four chemical resistance inducers on Maradol papaya to reduce Phytopthora nicotianae var. parasitica infections in rainfed crops at Chontalpa, Tabasco, Mexico. Design/methodology/approach: Three doses of four resistance inducers were tested on 60-day-old papaya plants in a greenhouse with a randomized design, with four replications and 10 plants as experimental plots. Three days after the inducers' application inoculations with mycelium discs were made, there were negative and positive control treatments to evaluating their efficiency by applying Abbott's formula. Results: The four chemical inducers for resistance (sodium silicate (SS), potassium silicate (PS), potassium phosphite (PF) and acibenzolar-s-methyl (ASM)) were statistically different from the control (P &lt; 0.0001**). The inducers SS 1 %, PS 1 %, FP 0.35 % and ASM 0.1 mM showed higher effectiveness (81.2, 75.9, 74.7 and 74.0 %). Study limitations/implications: The retained effective concentrations were tested in a single application, and their durability is unknown, so this point should be broadened. however, it may be an alternative for repeated use after transplanting. Findings/conclusions: Optimal concentrations of SS, PS, FP, and AMS, that respond against P. nicotianae var. parasitica infections can reduce damages in rainfed crops.

Common bacterial blight (CBB) caused by Xanthomonas axonopodis pv. phaseoli is the most destructive bacterial disease affecting all bean varieties in production areas. In this study, the effectiveness of different copper preparations against CBB disease on dry beans of Alberto variety, which are widely grown in Konya and Afyonkarahisar provinces with different climatic characteristics, were investigated. In field conditions, after 5-week-old bean plants were inoculated with a bacterial suspension of 108 CFU mL-1 of high virulent Xap k133 isolate, and subsequently twice every with 5 days intervals after inoculation, copper hydroxide, copper sulphate pentahydrate, copper oxychloride + copper hydroxide and copper oxychloride were applied at the doses recommended by the manufacturers. Disease severity (%) and disease score were evaluated using the 0-9 scale, and the effectiveness of the chemicals was compared with the control plants sprayed with water and determined with the help of the Abbott formula. According to the statistical data obtained, the most effective copper compound was determined by the application of copper oxychloride with 42.59-47.25% efficiency rates, copper sulphate pentahydrate had the lowest efficiency with about 7.69-12.96%. In addition to the negative effects of excessive use of copper in agriculture on the environment and human health, copper-resistant strains develops in bacterial pathogens. In order to determine the most effective copper compounds against CBB disease in dry beans in our country, the effectiveness of used as common compounds have been investigated for the first time and an organic and environmentally friendly sustainable bean production is revealed by using less copper.

Erwinia amylovora, the causative agent of fire blight disease, threatens a lot of species of the Rosaceae family. Antibiotics and copper compounds in chemical applications are most frequently are applied, but these can be phytotoxic and cause resistant strains of the pathogen. In our experiments, 20 herbal materials were tested for their antimicrobial effectiveness against the fire blight pathogen in vitro and in planta. The air-dried plants ground into fine powder and extraction was performed at room temperature by maceration with 80% (v/v) methanol/distilled water. The minimum inhibitory concentration values were determined by using disc diffusion method and streptomycin was used as control in all experiments. Antimicrobial activity was evaluated by measuring the inhibition zones in reference to the pathogen. Among the tested plants, Szygium aromaticum, Thymus vulgaris and Rhus cararia showed a good antibacterial activity and they inhibited the growth of E. amylovora with inhibition zone diameter ranging from 21 to 27 mm at 20% (w/v) in absolute methanol compared to streptomycin (31 mm) in vitro conditions. In vivo tests were performed by using highly virulent E. amylovora isolate (Eak24b, 91%) grown on TSA medium and inoculation on young shoots of 3-year-old Gala variety of apple and Santa Maria variety of pear seedlings at 107 CFU ml-1 density of the pathogen. Disease severity (%) was assessed by by proportion of blighted shoot length to the whole shoot length and also efficacy of the extracts was determined by using Abbott formula. The highest efficacy was obtained by S. aromaticum and T. vulgaris extracts of reducing shoot blight of cv. Gala and cv. Santa Maria by 67.81% - 64-12% and 51.50% - 51.04% ratios, respectively. Obtaining results showed that some medicinal and aromatic plant extracts might be used against fire blight disease as potential new generation chemicals on pome fruits within integrated and organic control programs.

Repellency effect of Pilocarpus spicatus A. St.-Hil essential oil and nanoemulsion against Rhipicephalus microplus larvae

Evaluation of a plant-based food supplement to control flea populations in dogs: A prospective double-blind randomized study

Currently, agricultural production is impossible without the use of chemical plant protection products, so the search for new effective fungicides is an important and urgent task. A significant part of the systemic fungicides and antimycotics used today are azole derivatives. Research conducted at the Department of Chemistry is devoted to the analysis of the fungicidal and biological activity of substances of various classes of organic compounds, including derivatives of azoles. Previously published data on the fungicidal activity of 2-methyl-5-nitrobenzoxazole and its derivatives showed that 2-methyl-5-nitrobenzoxazole shows the highest fungicidal activity for all types of fungal cultures used in the study. The second nitro group introduced into the 2-methyl-5-nitrobenzoxazole molecule reduces fungitoxicity by 1.5-2 times. Replacing the methyl group with phenyl significantly reduces the fungicidal activity. In continuation of these studies, tests of 5-(4'-chlorophenylazo)-7-nitro-8-hydroxyquinoline, 5-(3',5'-dimethoxyphenylazo)-7-nitro-8-hydroxyquinoline and 5-(3'-methyl-4'-nitrophenylazo)-7-nitro-8-hydroxyqui-noline with respect to V. inaequalis, the causative agent of apple scab, R. solani, the causative agent of rhi-zoctonia, F. oxysporum, F. moniliforme, causative agents of cereal crops, B. sorokiniana – causative agent of root rot and S. sclerotiorum – causative agent of white rot. The radial growth of mycelium was determined according to the method developed by NIITEKHIM, according to which the fungal cultures were sown in nutrient media with the addition of the studied substan-ces. In parallel, a control experiment was conducted in the aquatic environment. The growth of mycelia was controlled by measurements on days 3, 6 and 9. The percentage of inhibition of fungal growth was calculated using the Abbott formula. Analysis of the experimental data demonstrates a higher fungicidal activity of 5-(3',5'-dimethoxy-phenylazo)-7-nitro-8-hydroxyquinoline compared with other azoquinolines for all types of fungal cultures used in the study.

&lt;p&gt;&lt;em&gt;Meloidogyne incognita&lt;/em&gt; is one of the main biological agents that affects tomato production, alternatives to chemical pesticides are currently being evaluated, looking for compounds for nematode control. The objective of the study was to evaluate the nematicidal activity of limonene, allyl isothiocyanate, eucalyptol (2000, 1000, 500, 250, 100 and 0 ppm), β-citronellol (200, 100, 50, 25, 10, 0 ppm) and azadirachtin (12000, 10000, 8000, 6000, 4000, 0 ppm), on J2 of &lt;em&gt;M. incognita&lt;/em&gt;. Samples were carried out in greenhouses in the State of Morelos, where soil and root samples were taken, to obtain the nematodes. The bioassays were carried out following the Cristóbal - Alejo methodology, in a controlled environment, the biological activity of five compounds was evaluated, under six treatments with five repetitions each; and as an experimental unit a Petri dish with 30 juveniles (J2) of &lt;em&gt;M. incognita&lt;/em&gt; was used and 3 mL of each concentration was added to see the mortality response, the evaluations were carried out at 24 hours considering dead individuals they responded to the stimulation of the entomological pin, the correction of mortality was made by Abbott's formula and the mean lethal concentration was obtained using SAS 9.0. The mortality results were between 12 and 87.9%, however; &lt;em&gt;β-&lt;/em&gt;citronellol was the one that presented the highest mortality rates and lowest LC50, so it can be considered as an alternative for nematode control.&lt;/p&gt;

ABSTRACT Aleurocanthus woglumi Ashby (Hemiptera: Aleyrodidae) is an important pest of many plant species in particular citrus species. The aims of this study were: (1) to observe ;'in vitro'; biological aspects in three hosts and (2) to evaluate the bioactivity of plant species on immature A.woglum. Aqueous neem extract (Meliaceae), cassava wastewater, pepper sauce and gravy peduncle floral carnation guinea button and commercial neem were used in the experiment. Egg viability (%), nymphal period duration, nymphal mortality (%), puparium stage duration and pupae viability (%) were evaluated in 50 egg positions, with minimum of five eggs in "Pera" orange, mango and malay apple leaves obtained in the field. The insecticide effect (translaminar action and direct spray) at different concentrations on immature A.woglumi was evaluated. The first bioassay conducted to evaluate the bioactivity of species by translaminar action, each sample unit corresponded to three leaves, with minimum of 20 eggs and 20 1st instar nymphs, the variables were unviable eggs and nymph mortality (%); the experiment had a completely randomized design with four replications. In the second bioassay, fully infected branches were sprayed on upper and lower face of leaves with all treatments. Leaves with at least 40 eggs and 40 1st instar nymphs were marked, and mortality (%) and emergence (%) of adults were evaluated for seven days; each sample unit was represented by 40 eggs and 40 1st instar nymphs and the experiment had a completely randomized design with four replications. The average duration of the nymphal period ranged from 7.76 to 24.18 days in 'Pera'; orange, and from 8.86 to 25.20 days in mango. There was no significant difference between the viability of eggs and nymphs in ;'Pera'; orange and mango or pupae viability between ;'Pera'; orange and malay apple. Treatment efficiency was evaluated using the Abbott's formula [E(%) = T-I/T x 100], where E ( % ) = efficiency percentage, T = number of live insects in the control treatment and I = number of live insects in treatment with insecticide. Therefore, in the first bioassay conducted to evaluate the bioactivity of species by translaminar action, all treatments showed efficiency greater than 50%. In the second bioassay by direct spraying to cassava wastewater (100% and 50 %) and commercial neem oil (1%), treatment had nymphal mortality efficiency greater than 80%.

Background and Aims Xylotrechus arvicola (Coleoptera: Cerambycidae) is a new vineyard pest. Six insecticides were tested on X. arvicola eggs arranged in Petri dishes and in two parts of the vine: branch and trunk. Method and Results According to the Abbott formula, on Petri dishes, chlorpyrifos had total ovicidal control, significantly different from that of pyriproxyfen (88.3%), Beauveria bassiana (84.3%) and imidacloprid (80.9%). On branches, chlorpyrifos (91.6%), pyriproxyfen (79.1%) and flufenoxuron (75.0%) showed improved toxic effect, and on trunks, chlorpyrifos (83.3%) gave the best control, significantly different from that of imidacloprid (50.0%), pyriproxyfen (45.8%) and flufenoxuron (37.5%). Larval mortality was registered from the seventh to the fourteenth day after treatment: spinosad (50.0%), imidacloprid (45.8%) and B. bassiana (33.3%) were the insecticides that showed greater larval mortality on branches. These insecticides also showed greater larval mortality on trunks, but only B. bassiana (50.0%) had a greater residual effect on trunks than on branches. Conclusions All insecticides evaluated gave better ovicidal control when applied directly on Petri dishes than when applied on branches and trunks, where all insecticides (except chlorpyrifos and imidacloprid) show greater toxic effect when applied on branches. Spinosad and B. bassiana have the best larval residual mortality, when applied, respectively, on branches and on trunks. Significance of the Study Beauveria bassiana is the best insecticide with residual effect on neonate larvae on trunks, where the greater thickness of the rhytidome and cracks favoured the development of this fungus to invade actively the larvae through their shell and proliferate inside.

Plant diseases generate challenging problems in commercial, agriculture and pose real economic threats to both conventional and organic farming systems. The red palm weevil (Rhynchophorus ferrugineus) (RPW) is one of the most destructive pests of palms in the world. Nowadays, control methods revolve around treatments based on chemicals, biotechnological systems using semi-chemicals or the development of the sterile insect technique (hardly sustainable at this time) and biological control. Biological control as the use of natural microorganisms, extracted products from microorganisms or genetically improved to resist or eliminate of pathogens. Our aim was to evaluate the entomopathogenicity of indigenous Beauveria bassiana and Metarhizium anisopliae obtained in Gaza strip against larvae and adults of R. ferrugineus in order to identify indigenous strains potentially suitable for Red Palm Weevil biological control. B. bassiana & M. anisopliae were isolated from larvae and adult dead of RPW from different position of Gaza strip. Morphological analysis of the isolated fungi and molecular identification was determined using PCR technique. Also, the efficiency of the isolated fungi were evaluated under lab conditions and optimized as a biological agent. On the anther hand, the ability of treated RPW male to infect females is examined and calculated using Abbott's formula. Our results showed that the B. bassiana and M. anisopliae exhibited a good biological control agent against larvae and adults of RPW. The pathogenicity of the two most virulent isolates and the toxicity assay on larvae showed a highest mortality percentage nearly to 100% by 6 days after spraying the larvae with 3.4 × 108 spores/ml of B. bassiana. The mortality percentage reaches to 90% after spraying the larvae with 3.6 × 108 spores/ml of M. anisopliae. The mortality for the adults treated with pesticide arrives to 50% and the control group 10% at the same time. The results revealed that the infection of the adult males by Entomopathogenic fungi (EPF) can be disseminated into the healthy population, after RPW treatment with B. bassiana and M. anisopliae. Our research concludes that B. bassiana and M. anisopliae locally isolated can be used as biological very effective.

Accuracy and precision of alternative estimators of ectoparasiticide efficacy