Honey bee (Apis mellifera) colony strength and its effects on pollination and yield in highbush blueberries (Vaccinium corymbosum)

Many pollination studies with honey bees have examined the effect of colony density on crop yield and yet overlook the effect of variation in the population size of these colonies. High colony density in northern highbush blueberry has been met with concerns from beekeepers who feel higher densities will intensify outbreaks of European foulbrood (EFB, Melissococcus plutonius, Truper and dé Clari), a honey bee brood disease. The purpose of this study was to confirm the prevalence of EFB in colonies pollinating blueberries and to determine whether field-level variation in the population of adult workers in colonies explained variation in blueberry fruit set and/or yield. We addressed these objectives over the course of two production seasons at 13 commercial blueberry fields in Oregon, USA, stocked with identical densities of 10 colonies/ha. We confirmed that all colonies had negligible symptoms of EFB at the start of blueberry pollination, but 53% of colonies in 2019 and 41% in 2020 had symptoms immediately following the pollination season. We also validated a method for rapidly assessing adult honey bee colony populations, namely by counting the rate of foragers returning to colonies, and it was found to be strongly correlated to true internal adult bee population independent of year and ambient temperature at the time of evaluation. Using returning forager counts, we determined there was considerable variation in the average population of colonies at each field, ranging from an estimated 10,300 to 30,700 adult worker bees per colony. While average colony strength did not predict variation in fruit set, it was related to variation in yield, independent of year. Our linear model of flight count (as a proxy for colony strength) predicts estimated yield increases of up to 25,000 kg/ha of blueberries could be achieved by colonies stronger than the recommended six frame minimum, suggesting that higher pollination benefits could be achieved without increasing hive density if stronger colonies are promoted.

Descriptive Epidemiology in Allergic Rhinoconjunctivitis in the Last 5 Years in Northern Mexico

Purpose: To determine the frequency of allergic conjunctivitis in the period from 2015 to 2020 at the Regional Center of Allergy and Clinical Immunology of the University Hospital “Dr. José Eleuterio González” in Monterrey, Nuevo Leon, Mexico. Methods: Observational, retrospective and descriptive study. The database of all patients with diagnosis of allergic rhinoconjunctivitis seen in the outpatient clinics from January 2015 to May 2020 was reviewed. Results: The incidence from 2015 to 2020 of allergic rhinoconjunctivitis in the Regional Center of Allergy and Clinical Immunology was 1.5% in 2015, 2.7% in 2016, 2.8% in 2017, 3.2% in 2018, 4.2% in 2019 and 2.3% in 2020. The age group with the highest frequency for allergic rhinoconjunctivitis was found in those over 18 years of age; no significant difference was found between men and women. The year 2019 had the highest number of cases. The most common positive allergens in the skin tests of these patients were Dermatophagoides, Cynodon dactylon and Fraxinus americana, for the last two their pollination season were parallel to the peaks where the highest number of consultations were registered in March, April and August. Conclusions: Allergic rhinoconjunctivitis is a disease that has been increasing in recent years and despite the economic and labor burden it represents, there are currently few studies that address the epidemiological characteristics of these patients.

Important issues of fungal sensitization: aerobiological aspects

Aim: to assess the dynamics of mold sporulation in Samara to predict the risk of allergy development and exacerbation. Patients and Methods: mold spore samples were collected from April 1 to September 30 in 2016–2019 using trap impactor and placed on slides coated with Vaseline-wax mixture. Mold spores were calculated and referred to various taxa. Allergy risks were predicted. Thresholds for evoking asthma are estimated to be 100 spores/m3 for Alternaria and 3,000 spores/m3 for Cladosporium. Results: in Samara, average mold vegetative period was 164 days. Cladosporium and Alternaria spores were identified. Their spores were estimated as 34.4% of total atmospheric spores in Samara. Cladosporium spores estimated as 15.3% of total fungal spores were identified during the whole observation period. Maximum concentration was less than 960 spores/m3 having been within the average range. Alternaria spores were estimated as 19.1%. The proportion of days exceeding the threshold value of 100 spores/m3 was 6% to 81% having been the highest in July-September. Conclusion: prerequisites for the development of fungal sensitization were revealed. Regional specificity of sporulation in Samara was illustrated. Major mold taxa were identified. Allergy risks in Alternaria and Cladosporium sensitization were assessed. The highest total average monthly amount of Alternaria spores was during Artemisia and Ambrosia pollination season. This could be challenging for the diagnosis and treatment of patients suffering from allergic symptom exacerbations during this period. Our findings will improve the diagnosis, treatment, and prevention of allergic disorders in Samara. KEYWORDS: aerobiological monitoring, allergy, mold spores, Cladosporium, Alternaria, fungal sensitization. FOR CITATION: Mazokha K.S., Manzhos M.V., Khabibulina L.R. et al. Important issues of fungal sensitization: aerobiological aspects. Russian Medical Inquiry. 2021;5(1):4–9. DOI: 10.32364/2587-6821-2021-5-1-4-9.

Alder pollen season in selected cities of Poland in 2020

This paper presents the course of alder pollination season in Poland in 2020. The measurements were performed in Bydgoszcz, Bialystok, Lublin, Olsztyn, Opole, Piotrkow Trybunalski, Sosnowiec, Szczecin, Warsaw, Wroclaw and Zielona Gora. Volumetric method with the use of Volumetric Spore Trap (Burkard, Lanzoni) was implemented. Pollen season was defined as the period in which 95% of the annual total catch occurred. The alder pollen season in 2020 started about 10–30 days earlier compared to 2017–2019. The pollen season started first in Szczecin, Opole and Zielona Gora (in the second half of January). In the other cities alder pollen season started in first half of February. The highest daily pollen count was recorded in Lublin (1211 P/m3). In other cities the maximum concentrations ranged from 160 P/m3 in Sosnowiec to 465 P/m3 in Piotrkow Trybunalski. The highest alder pollen concentrations were detected in the first decade of March (March 1st–3rd). Only in Zielona Gora, Wroclaw, Opole and Sosnowiec the maximum concentration was recorded in the third decade of February. The annual pollen sum of Alnus in 2020 was even 5–10 times lower than in years 2019.

Correlated dynamics of serum IGE and IGE+ clonotype count with allergen air level in seasonal allergic rhinitis

Mechanisms of maintenance of immunological memory in the chronic course of seasonal allergic rhinitis remain poorly understood. The detailed understanding of these mechanisms is required for design of new approaches for allergy treatment. It is known that the level of allergen-specific IgE antibodies (sIgE), which play a key role in the development of the disease, is increased in patients with seasonal allergic rhinitis during pollination season. This study aimed to investigate the dynamics of serum IgE levels and characteristics of the clonal repertoire of IgE-secreting lymphocytes depending on the intensity of the patient's contact with the allergen. For three patients, allergic to birch pollen (22, 22, and 28 y.o.), we measured total IgE and birch pollen specific IgE levels at 6 time points with 2 week interval during the birch pollination season. Immunoglobulin heavy chain gene (IGH) clonal repertoire data for several B-cell subpopulations at different time points were obtained for one patient. We observe growth of the sIgE level (91%, 37%, and 64% compared to the baseline) at the peak of pollination season in all three donors. Initial increase in sIgE and IgE levels coincides with the birch pollination initiation; sIgE and total IgE levels correlate with the birch pollen air level (sIgE: R2 = 0.98 at p < 0.05; total IgE: R2 = 0.95 at p < 0.05). We detected IgE clonotypes only in samples obtained during the birch pollination, which indicates an increase of IGE-expressing cells concentration during this period. The frequency of IgE clonotypes was extremely low compared to that of the clonotypes of other isotypes (IgE — 0.01%, IgM — 48.4%, IgD — 14%, IgG — 17.4%, IgA — 19.8%). Hypermutation and phylogenetic analysis of the sequences from the 13 detected IgE-containing clonal groups showed that these IgE clonotypes could originate from IgG as a result of sequential isotype-switching.

Field Studies on Dynamic Pollen Production, Deposition, and Dispersion of Glyphosate-Resistant Horseweed (Conyza canadensis)

Glyphosate-resistant (GR) horseweed has become an especially problematic weed in different crop production systems across the United States and the world. In this field study, we used a nondestructive measurement system to analyze the pollen production, deposition, and dispersion of a Tennessee glyphosate resistant (TNR) horseweed biotype in Knoxville, TN during the 2013 pollination season. We observed that the pollination season of TNR horseweed lasted about 2 mo (54 d). About 78.93% of horseweed pollen was released between 9:00 A.M. and 7:00 P.M. during each sampling day and the release peak was at about 1:30 P.M. The seasonal release of pollen grains was estimated to be 5.11 million grains plant−1. The release rate data indicated that the integrated horizontal flux density and deposition flux density contributed to 78.17% and 21.83% of the release rate, respectively. We also found that pollen concentration decreased with distance from the source field; the average pollen concentration decreased to 50.69% at a distance of 16 m from the source plot. This is the first result of a systematic, direct examination of the release rate (emission and deposition), release pattern (daily and seasonal), and dispersion pattern of GR horseweed pollen.

Reproductive success of orchard and nonorchard pollens during different stages of pollen shedding in a Scots pine seed orchard

The reproductive success of orchard and nonorchard pollens was studied in seeds from megastrobili exposed during different stages of pollen shedding in a Pinussylvestris L. seed orchard. Wind pollination was controlled experimentally by isolating and then temporarily exposing the megastrobili to four different stages of pollen shedding by orchard trees. The amount of pollen contamination in the seed crop was determined using isozyme markers and an undetected gamete model. The estimated level of pollen contamination was 48% when megastrobili were exposed during the entire pollination season. Contamination was highest (60%) when megastrobili were exposed before actual pollen shedding by orchard trees, and lowest (27%) in seeds from megastrobili exposed during maximum pollen shedding by orchard trees. Reproductive success was measured several ways: as the total number of seeds produced in each treatment, as the ratio or proportion of mature cones per megastrobilus, and as the number of seeds produced per cone or megastrobilus. In 1991, reproductive success was highest before maximum pollen shedding by seed orchard trees. Pollen shedding by orchard trees occurred a few days after most megastrobili became receptive.