Bud Mite Research Articles

Dynamics of damage by the buddle mite (<i>Cecidophyes ribes</i> West.) to collection varieties of black currant

The aim of research is to evaluate collectible black currant material according to resistance to bud mite in conditions of Kirov region, to study the dynamics of damage accumulation by a pest and to distinguish the varieties which have been showing the resistance for a long time. The evaluation of varieties had been held on the collectible plantations of fruit and berry crops of laboratory of FSBSI FARC of the North-East (Federal State Budget Scientific Institution “Federal Agricultural Research Centre”) (Kirov) which is situated in a central agro-climatic zone of Kirov region in 2014–2021. 36 black currant varieties of 2013 planting year were included in the research. The check variety is Vologda. The scheme of planting is 3.0 × 1.0 m, 5 plants on an every accounting plot. The repetition is single. As a result of a long-term study of the dynamics of bud mite damage accumulation, the varieties, which remain free from the pest longer than others were distinguished: Alexandrina (the features of the pest had not been noticed during the whole research); Dobriy Jinn (Kind Genie) and Gulliver (5.6% of the number of the studied) which showed the first damage on the 7th and 8th year after planting. Chishma, Yadrenaya, Mila, Vasilisa, Sputnick, Nezhdanchick (16.7%) showed the first features of damage on the 5th year of planting. The varieties with the resistance to a bud mite (47.2%) are promising as a basic material for bringing in a selection process and recommended for the production. The varieties with middle and low resistance to the pest can be recommended for amateur and commercial horticulture but as a basic material on resistance to a phytophage in selection, they are unsuitable. The analysis of a link between a degree of pest damage of studied varieties and productiveness showed an average negative relationship between these features (r = –0.62).

Can Pest Management and Cultivar Affect Phytoptus avellanae Infestations on Hazelnut?

The big bud mite Phytoptus avellanae is a resurgent pest of hazelnut, Corylus avellana, causing substantial yields reductions in many productive areas. Mites colonise and develop within healthy buds which become swollen, with subsequent alteration to the plant's development. To date, there has been limited knowledge on how the cultivar and pest management strategies affect infestations. This study explored these aspects through two ad hoc experiments carried out in central Italy. In the first experiment, the susceptibility of 11 cultivars with different geographic origins was tested in a germplasm hazelnut collection. The second experiment assessed the infestation level in orchards with integrated pest management (IPM) and organic pest management strategies and in a renaturalised environment (a former agricultural area now converted in a natural park). The results showed that the most and the least susceptible cultivars were Tonda Gentile and Nocchione, respectively. No significant differences were found between IPM and organic management, but they were both different to the renaturalised environment. The outcomes of this research can serve as a valuable reference and can be applied to all current or potential hazelnut cultivation areas characterised by the same environmental conditions.

Genomic and Pathogenic Characterization of Akanthomyces muscarius Isolated from Living Mite Infesting Hazelnut Big Buds.

The capability of entomopathogenic fungi to live as plant endophytes is well established. However, their presence in undiscovered environmental niches represents the beginning of a new challenging research journey. Recently, Akanthomyces muscarius (Ascomycota, Cordycipitaceae) (Petch) Spatafora, Kepler & B. Shrestha was isolated from hazelnut buds infested by the big bud mite pest Phytoptus avellanae Nalepa, which makes the buds swollen, reddish, and unable to further develop. Gall formation is known to be regulated by a consortium of microbes and mites, and to better understand the possible role of A. muscarius within the infested gall, its whole genome sequence was obtained using a hybrid approach of Illumina and Nanopore reads. The functional and comparative genomics analysis provided within this study may help answer questions related to the ecology and the entomopathogenicity of this fungus.

Revised description of the blueberry bud mite, Acalitus vaccinii (Acari: Trombidiformes: Eriophyidae), and a key to all Eriophyoidea on Vaccinium

In 2014 the blueberry bud mite, Acalitus vaccinii (Acari: Trombidformes: Eriophyidae), was detected in the Mpumalanga province of South Africa for the first time causing significant damage to cultivated blueberries. This was the first detection of this pest outside of North America, to which it is native. However, its taxonomic description at that time lacked critical detail and omitted characters and life stages important for easy and accurate identification. Using an integrative taxonomic approach, we combined phase contrast light microscopy with low-temperature SEM and DNA barcoding data to revise the description of A. vaccinii using South African specimens. Additional characters not included in previous descriptions but reported here are the h1 (accessory) setae, leg I & II u’ (mesal) setae, and leg II bv (femoral) setae. Detailed descriptions and measurements of all life stages are included, along with a discussion of morphological variation and biology. Two DNA sequences of common barcode regions (nuclear and mitochondrial) are provided to further aid in identification. In addition, a key to all known species of eriophyoid mites present on Vaccinium is provided.

Assessment of applying an integrated pest management strategy to control the raspberry leaf and bud mite, Phyllocoptes gracilis (Nal.) and its effect on the raspberry leaf metabolites

In the years 2018‒2020, the effectiveness of three synthetic active substances (acequinocyl, fenpyroximate, spirodiclofen), one substance derived from Streptomyces spp. (abamectin), a plant extract (orange oil) and silicone polymers in controlling Phyllocoptes gracilis in two Polish raspberry plantations (v. ‘Glen Ample’) was assessed. All the substances showed high and comparable efficacy against the tested pest, significantly reducing its population. However, their effects occurred at different times after the application. The strongest immediate control was shown by silicone polymers, followed by abamectin and spirodiclofen. The full effect of fenpyroximate application was visible after approx. 2 weeks, while acequinocyl was effective 3‒4 weeks after the application. Moreover, the content of phenolic compounds, sterols and triterpenoids was determined in leaves of plants treated with spirodiclofen, orange oil and silicone polymers. The observed increase in the content of salicylic acid and changes in the content of triterpenoids in leaves may indicate a stimulating effect of the substances to the natural defense processes of plants.

Biology of Apricot Bud Gall Mite, Acalitus phloeocoptes Determining the Emergence Time of the First Generation Using the Degree Day Model and Its Control

Nourpour, F., S. Aramideh, S. Mirfakhraie and H. Kamali. 2024. Biology of Apricot Bud Gall Mite, Acalitus phloeocoptes Determining the Emergence Time of the First Generation Using the Degree Day Model and Its Control. Arab Journal of Plant Protection, 42(3): 275-280. https://doi.org/10.22268/AJPP-001255 The plum bud gall mite, Acalitus phloeocopte Nalepa (Acari: Trombidiformes) is one of the important pests of plum trees. The biology and control of this mite during the 2021-2022 period was investigated. The results obtained showed that this mite had four generations a year and spends the winter as adult female mite. The estimated degree days (DD) for the emergence of 50% of wintering mites with two temperature thresholds of 6.2 and 5.8°C degrees were calculated as 68.50 and 88.00 DD in 2021 and 72.00 and 90.50 DD in 2022, respectively. The number of new galls formed by this mite following different treatments such as volck oil (as winter oil), liquid sulfur, propargit, phenpyroxymit, abamectin, tetradifon and sunmite along with water as a control treatment was determined. The results showed that in 2021, the sulfur treatment led to the least number of new galls 14.22±0.53, whereas in 2022 abamectin gave the least number of new galls 17.70±1.32. The integrated pest/crop management including pruning and removing infested branches in winter, a foliar spray with 80% liquid sulfur at the end of winter before budding or spraying with abamectin using degree-days following 50% overwintering mite emergence from galls, gave the best results and is recommended for adoption by farmers. Keywords: Biology, degree day, plum bud mite, control, acaricides.

Esults of the study of black currant varieties on the complex of economically valuable traits in Kirov region conditions

The aim of the research is to study collection material of black currant in conditions of Kirov region and to identify varieties which combine high productivity, large fruits and resistance to bud mite (Cecidophyes ribes West.) and powdery mildew (Sphaerotheca mors-uvae (Schw) Berk et Gurt.). The researches had been held in an experimental garden of FSBSI FARC of the North-East (Kirov) in 2015-2021. The objects of the research were 36 black currant varieties of 2013 planting year. The check variety was Vologda. As a result of the research, source of the complex of economically valuable traits was distinguished: three varieties of Cherniy Zhemchug (Black Pearl), Chishma, Karachinskaya singled out for the combination of high productivity 62,3-142,0 c/ha (the exceeding of productivity over the check variety is 35,0% and more), for the large fruit (an average mass of a berry is 1,20 -1,70 g) and for high resistance to bud mite; the varieties Yadrenaya (Vigorous) and Gulliver were differed in a combination of high productivity 47,0 - 62,9 c/ha (the exceeding over the check variety is 35% and more), a large fruit (an average mass of a berry is 1,20 - 1,30), a high degree of resistance (the maximum degree of damage is 0,5 - 1,0 point) to powdery mildew and bud mite; two samples, Mila and Sputnik were identified for a combination of high productivity 46,7 - 49,6 c/ha (the exceeding of productivity over the check variety is 35,0% and more), for the large fruit (an average mass of a berry is 1,20 -1,80 g), a taste (4,0 points), a high degree of resistance (the maximum degree of damage is 0,5 - 1,0 point) to powdery mildew and bud mite. Complex resistance to powdery mildew and bud mite (the maximum degree of damage is 0 point during the research) was found in the Alexandrina variety.

Biology and management of big bud mites in Pacific Northwest (USA) hazelnut orchards

Biology and management of big bud mites in Pacific Northwest (USA) hazelnut orchards

Selection assessment of varieties and selected forms of black currant based on large fruit size

The article presents research findings on the weight of black currant berries. The research focused on the varieties and selected forms of black currant (Ribes nigrum L). Nara variety, adapted to local conditions, was used as a control. Studies were carried out in 2020–2022 at the plots for genetic collection and competitive trials of selected forms of black currants at the All-Russian Research Institute of Lupin (Bryansk region). The planting scheme involved a spacing of 3×0.8 m on grey forest soils. The observations were carried out using conventional methods. The varying weather conditions during the study period allowed for a more objective evaluation of the genotypes in terms of their adaptive capabilities and facilitated the selection of large-fruited and resistant forms. The most favourable meteorological conditions for berry weight development were observed in 2022. During this period, the average berry weight of the studied gene pool was 2.5 g. Among the examined varieties, Dobrynya (3.5 g), Debryansk (2.7 g), Chara (2.6 g) and Selechenskaya 2 (2.6 g) demonstrated the largest berry sizes with variation coefficients of 20%, 28%, 7%, and 17%, respectively. Large-fruited forms having an average berry weight exceeding 3 g and high stability (V=3%) were selected from the hybrid family 6-12- 224×6-26-207 – 7-3-227 (3.6 g), 7-3-213 (3.4 g), 7-19-100 (3.6 g) and Selechenskaya 2×Treasure – 6-20-67 (3.5 g). These genotypes represent valuable parent material for further breeding aimed at increasing berry weight. New large-fruited sources with a combination of important breeding traits (large fruit, high vitamin C content, resistance to powdery mildew and bud mite), namely,7-19-100, 7-3-227, 7-18-250, 7-13-232 and 7-17-150, were identified. The variety Dessert Olkhina exhibited the smallest berries (0.8 g) with a variability of 20%. The influence of weather conditions on the weight of berries was established, revealing a positive average correlation between berry weight and precipitation levels from May to July (r=0.52) and the hydrothermal index of the growing season (r=0.56).

Determination of Hazelnut Bud Mite Species and Contamination Rate in Hazelnut Orchards in Duzce Province

Bu çalışma Düzce ilinde fındık yetiştiriciliğinin en fazla yapıldığı üç ilçede (Akçakoca, Merkez ve Cumayeri) fındık bahçelerinde bulunan zararlı fındık kozalak akar türlerini ve bulaşma oranını tespit etmek amacıyla toplam 40 bahçede 2021-2022 yılları arasında yürütülmüştür. Fındık bahçelerinin büyüklüğü dikkate alınarak örneklemelerde her bir bahçede rastgele belirlenen en az 10’ar ocakta gözle kontrol yöntemi ile ağacın yaprak, sürgün, tomurcuk, çiçek ve meyve gibi organları incelenmiş ve toplanan örnekler polietilen torbalar ile laboratuvara getirilmiş ve kaydedilmiştir. Elde edilen bireylerin preparatları hazırlanarak tür teşhisi yapılmıştır. Ayrıca, örneklemelerde her bir bahçede en az 10’ar ocakta ve her ocaktan seçilen birer daldaki kozalakların sayımı yapılmıştır. Örnekleme yapılan bahçelerde zararlının bir tek bireyi veya zararı tespit edildiğinde o bahçe bulaşık olarak kaydedilmiş ve bulaşma oranı belirlenmiştir. Çalışmada Phytoptus avellanae Nal. (Trombidiformes: Phytoptidae) ve Cecidophyopsis vermiformis (Nal.) (Trombidiformes: Eriophyidae) olmak üzere iki tür tespit edilmiştir. Phytoptus avellanae türü iki kriptik türden oluşan bir kompleksi temsil etmektedir. Her üç ilçedeki fındık bahçelerinde zararlı ile bulaşma oranının %100 olduğu ve kozalak yoğunluğunun ekonomik zarar eşiğinin üzerinde olduğu saptanmıştır. Bahçelerde dal başına kozalak ortalaması en yüksek Cumayeri ilçesinde (16,4 kozalak sayısı/dal) tespit edilmiş, bunu sırası ile Akçakoca ilçesi (6,5-9,25 kozalak sayısı/dal) ve Merkez ilçe (7,16-8,85 kozalak sayısı/dal) takip etmiştir. Fındık kozalak akar popülasyonunun mücadeleyi gerektirecek düzeyde olduğu ve son yıllarda fındıkta verimini etkileyen önemli faktörler arasında yer aldığı görülmüştür.

Evaluating response variables to the reversion of the ‘engurruñadera del cacao’ through the control of Aceria reyesi (Nuzzaci) (Acari: Eriophyidae) with abamectin and pruning

The cacao bud mite, Aceria reyesi (Nuzzaci), has been identified as the causal agent of the ‘engurruñadera del cacao’, characterized by the apparent accumulation of stipules on the buds, followed by die-back, with premature fall of leaves, shortening of internodes and proliferation of lateral branches, or witches’-broom, resulting in production losses or even in the death of plants. Our objective was to evaluate four response variables (numbers of leaves/plant, stipules/bud, internodes/branch and branches/plant) that could be indicative of a possible reversion of the ‘engurruñadera’ after the application of the acaricide abamectin and/or pruning. Two experiments were carried out between November 2020 and April 2021 in a greenhouse at UESC, with cacao seedlings of the genetic group ‘Forastero’ (cacao ‘Common’) infested with A. reyesi and showing typical symptoms of the ‘engurruñadera’. The first experiment was conducted with 4 treatments and 8 replicates, with the application of (1) Abamectin + pruning, (2) Abamectin without pruning, (3) Water + pruning and (4) Water without pruning (control). Sprays were carried out fortnightly with an Abamex® solution (18 g/L of abamectin, in a concentration of 2 mL/L of distilled water + neutral detergent). Pruning was performed only once, at the beginning of the experiment, by removing the apical 10 centimeters of all plant branches. Response variables were evaluated one day before the application of the treatments (Day 0), and afterward (~Days 75 and 150 after the first evaluation, respectively). The second experiment was conducted with 2 treatments and 12 replicates, with the application of (1) Abamectin (treated) and (2) Water (control). Pulverizations and evaluations were carried out as in the first experiment. The number of leaves/plant and internodes/branch were the only response variables that indicated some reversion of the ‘engurruñadera’ in both experiments among treated and control groups, although only 150 days after the application of abamectin and/or pruning. The number of branches/plant showed a significant increase from 75 days after the treatments with pruning, and no difference was found among treated and control groups in terms of numbers of stipules/bud in both experiments. We concluded that the numbers of leaves/plant and internodes/branch seem to be adequate monitoring tools to indicate the reversion of the ‘engurruñadera’ after the application of abamectin and/or pruning. Pruning was effective in the reversion of symptoms of the ‘engurruñadera’ on cacao seedlings as well as the abamectin application of a 2 mL dose of Abamex® per liter of water fortnightly.

RESULTS OF ENVIRONMENTAL TEST OF PILOT BLACK CURRANT VARIETY

The purpose of the study is replenishment of the assortment of black currant for the Volga-Vyatka region. The blackcurrant variety Pilot was bred in the conditions of the Middle Urals, at Sverdlovsk horticultural breeding station. It was obtained from free pollination of Valovaya variety. Pilot variety was tested in five regions of the Russian Federation - in the system of state variety testing and in various scientific and educational institutions under scientific cooperation agreements. The studies were carried out according to the "Program and Methodology for the Study of Fruit, Berry and Nut Crops" (Oryol, 1999). In 2021, Pilot variety deservedly replenished the assortment of black currant for cultivation in the Volga-Vyatka (4) region,it is also suitable for cultivation in other regions of the Russian Federation. Pilot variety can serve as a starting material for further improvement of the blackcurrant assortment. Brief morpho-biological description includes: the variety is winter-hardy, drought-resistant, high yield, in some years up to 240 dt/ha. The bush is medium or tall, semi-spreading;medium-term flowering, medium-late ripening of berries, self-fertility - 66%, a variety with high resistance to powdery mildew and bud mites. The leaves are little affected by septoria. Fruit raceme is medium. Berries are with an average weight of 1.5 g, maximum - 5 g, black, rounded, relatively one-dimensional. The taste is sweet and sour, the skin is dense, but not rough, the separation is dry. The nomenclature standards for blackcurrant varieties selected by Sverdlovsk Horticultural Breeding Station, including the Pilot variety (WIR-54127), included in the Herbarium of Cultivated Plants of the World, Their Wild Relatives and Weeds (WIR) have been published in co-authorship with the staff of FSBSIFederal Research Center All-Russian Institute of Plant Genetic Resources.

Population density of eriophyid mites (Acari: Eriophyidae) on raspberry (Rubus idaeus) and their association with leaf blotch symptoms

Red raspberry, Rubus idaeus, is known to be infested by at least six species of eriophyid mites. Among them, the raspberry leaf and bud mite, Phyllocoptes gracilis, (Figure 1, A–B) is the only known vector of a raspberry virus, namely the raspberry leaf blotch virus (RLBV) (Dong et al. 2016; McGavin et al. 2012; Tan et al. 2022). Raspberry leaf blotch (Figure 1, C), a leaf disorder displaying as leaf chlorosis, distortion and patchy necrosis, yellowing and thinning on lateral branches, has been attributed to the feeding of P. gracilis until RLBV was also found to be associated with these symptoms (McGavin et al. 2012). Previous sampling of eriophyid mites was often based on the presence of the leaf blotch symptom, and there is a reasonable doubt if the symptom was caused by RLBV infection or mite infestation. It could also be hypothesized that eriophyid mites are attracted to RLBV-infected plants as viruses could make host plants more attractive to vectors (Donnelly & Gilligan 2020; Shi et al. 2019). It is therefore important to improve the detection of both mites and RLBV to efficiently manage the virus. In addition, knowledge on the dominant infestation area of eriophyid mites on raspberry canes is essential to develop an effective pest management approach. Gordon and Taylor (1976) reported that P. gracilis on primocanes during late summer (mid-August) was dominantly found on the upper leaves, due to the presence of predatory mites on the lower and middle leaves. But mite behavior on floricanes is also important to study if the goal is to prevent mite migration and RLBV transmission to primocanes. This study aimed to investigate the population density of eriophyid mites on raspberry floricanes and the association of eriophyid mites, RLBV, and leaf blotch symptoms.

Monitoring the Bud Mite Pest in a Hazelnut Orchard of Central Italy: Do Plant Height and Irrigation Influence the Infestation Level?

Mite pests are a serious threat for hazelnut cultivations, causing economic losses every year. At least two species of big bud mites, Phytoptus avellanae (Acari: Phytoptidae) and Cecidophyopsis vermiformis (Acari: Eriophyidae), are involved in severe hazelnut bud infestations, even though few studies report P. avellanae as the most present and harmful. Great steps forward have been made in monitoring and management strategies of these mite pests, but a plethora of questions remains unanswered about their ecology and behaviour and how agronomical practices impact populations. Given this precondition, we conducted a four-year monitoring in an experimental hazelnut orchard located in the Viterbo hazelnut district, Central Italy, to: (i) explore the potential effect that irrigation has on mite infestations, (ii) assess if mites locate in a particular band height of hazelnut plants; and (iii) assess the overall field infestation over the years. This study showed that not-irrigated plants and plants irrigated by underground pipe systems were similarly infested. Mites tend to locate in the middle band of the plant, namely from 1.5 to 3 m from the ground. The four-year survey showed an overall increasing infestation trend, with a peak in 2021 for irrigated plants and 2022 for not-irrigated. These results are a milestone for further exploration of the biology and ecology of this pest and to formulate ad hoc monitoring and control strategies as well.

Non-target effects of agrichemicals applied in the fall or during the dormant season on subsequent development of Exobasidium leaf and fruit spot of blueberry

The basidiomycete Exobasidium maculosum causes Exobasidium leaf and fruit spot, an early-season disease of blueberry in the southern United States. Previous research suggested that the pathogen oversummers and overwinters epiphytically on the surface of blueberry bark and buds, most likely in its yeast stage. This is supported by the finding that a single dormant application of lime sulfur provides substantial control of the disease the following spring. As a surface resident for much of the year, E. maculosum is thus exposed to various horticultural and pest management practices which may affect its epiphytic population dynamics and impact subsequent disease development. The magnitude and consistency of such non-target effects was evaluated in multi-year field trials on susceptible ‘Premier’ and ‘Tifblue’ rabbiteye blueberry in southern Georgia. One fall application of stylet oil (timed to mimic sprays for blueberry bud mite control) or two fall applications of captan (timed to coincide with the management window for fungal foliar diseases) did not suppress Exobasidium leaf and fruit spot the following spring, whereas two fall applications of lime sulfur reduced the disease significantly (by 74.3% on average), albeit not to the same level as the late dormant lime sulfur standard (close to 90% average reduction across leaf and fruit spot intensity). A single late dormant spray of the growth regulator hydrogen cyanamide (a caustic compound with antimicrobial activity) suppressed disease intensity in most trials, but disease reduction was only partial (averaging 56.2% for leaf lesion density and 39.3% for fruit spot incidence). In contrast, a late dormant application of dormant oil consistently increased both leaf lesion density (by 80.7% on average) and fruit disease incidence (by 78.6%). The pronounced non-target effects associated with these off-season applications could explain variations in Exobasidium leaf and fruit spot risk among blueberry sites and years.

Toxic effects of some acaricides on Aceria oleae (Nalepa, 1900) (Acari: Eriophyidae) and its predator Neoseiulus californicus (McGregor, 1954) (Acari: Phytoseiidae) under laboratory conditions

Olive bud mite, Aceria oleae (Nalepa, 1900) (Acari: Eriophyidae) is one of the key pests that regularly needs control with acaricides in olive orchards of Bursa Province, Turkey. For the chemical control of A. oleae , it is critical the use of acaricides does not reduce the survival and fecundity of its natural enemies. The toxic effects of three concentrations of seven acaricides were assessed against both A. oleae and its predator Neoseiulus californicus (McGregor, 1954) (Acari: Phytoseiidae) using a residual method under controlled conditions at Bursa Uludağ University during 2020-2021. The highest recommended concentrations of acequinocyl, azadirachtin, fenbutatin oxide, milbemectin, pyridaben, spirodiclofen and sulfur killed A. oleae adults with rates varying from 80 to 100%. Two concentrations of milbemectin, pyridaben and sulfur showed high mortality rates. Nevertheless, highest recommended concentrations of acequinocyl, pyridaben, spirodiclofen and sulfur were found to be highly toxic to N. californicus adults with rates varied from 82 to 100%. The high mortalities for mobile immature stages and reducing in the fecundity of N. californicus occurred by highest recommended concentrations of all tested acaricides. Based on the scale recommended by the International Organization for Biological Control, some sublethal concentrations of fenbutatin oxide, spirodiclofen and sulfur were found to be slightly harmful to both mature and immature of N. californicus .

Study of elite black currant varieties selected at the Federal Agrarian Scientific Centre of the North-East

Elite varieties of black currant selected at the Federal Agrarian Scientific Centre of the North-East were studied with the purpose of identifying samples with an optimal combination of high productivity, large fruit, good taste, resistance to big bud mite and powdery mildew. The studies were carried out in 2015–2019 on a site located in the central agro-climatic zone of the Kirov region. 10 elite black currant varieties of 2013 planting were investigated. The varieties of Arkadiya and Vologda were used as control. The counts and observations were carried out using conventional methods. The combination of high productivity, its sustainability and high self-fertility was noted in varieties 71-2-07, 65-1-07 and 64-4-07. In terms of resistance to the pest, two highly resistant samples 71-2-07 and 65-1-07 were identified, which showed no signs of damage during the study period. The damage by big bud mite remained low across the entire experimental site. The average negative effect of big bud mite on the yield was found (r = -0.48). In the following 7 elite forms — 71-2-07, 65-1-07, 70-5-07, 46-1-07, 12-1-07, 15-1-07, 20-1-07 (70.0 % of the studied material), the maximum degree of damage by powdery mildew did not exceed 1.0 points, which indicates their high resistance. The combination of high resistance to big bud mites and resistance to powdery mildew was found in varieties 71-2-07 and 65-1-07. During the study period, 9 elite black currant varieties produced large-fruited berries. Out of these 9 forms, 3 (71-2-07, 64-4-07, 12-1-07) showed significantly higher values of this indicator compared to the Vologda control. Sample 27-1-07 was distinguished by a combination of large fruit, good taste and low acidity, as well as by high contents of ascorbic acid and dry matter. Sources of economically valuable traits were identified in 2 samples: 65-1-07 having a combination of high productivity, large fruit, high self-fertility, good taste, resistance to big bud mites and powdery mildew; 64-4-07 having a combination of high productivity, large fruit and high self-fertility. These genotypes can be recommended as a starting material for further breeding. On the basis of the results obtained, the Ariel variety (71-2-07) was forwarded to the State Variety Testing in 2020.

АНАЛИЗ ДИНАМИКИ ВИДОВОГО СОСТАВА ФИТОФАГОВ И ФИТОПАТОГЕНОВ СМОРОДИНЫ ЧЕРНОЙ

The article presents data on the phytosanitary state of black currant plantings grown in the Khabarovsk Territory for the period from 1960 to 2020. The aim of the study was to analyze the dynamics of the species composition of phytophages and phytopathogens of black currant. The objectives of the study were to conduct an analytical review of the species composition of pests and phytopathogens of black currant that developed on the plantings of the studied crop in the period from 1960 to 2020; and also to prepare a preliminary forecast of the dynamics of the species composition of pests of black currant culture. In the course of the work, it was revealed that in recent years, the phytosanitary background of plantings is made up of such crop pests as currant glassworm, common spider and currant bud mites, gooseberry shoot aphids. The degree of harmfulness of currant glass is especially high on old plantings and in some years the value of damaged shoots reaches 50-60%. Gooseberry shoot aphid is widespread everywhere and its harmfulness reaches up to 90%. The growth of the population of the currant kidney mite has been detected since the 1970s. and it continues to the present time, in some years this pest damages up to 80% of bushes. The common spider mite was in the stage of depression until the 90s of the last century. However, since the 2000s and up to the present time, its mass distribution has been revealed, which in some areas reaches 80%. Of the phytopathogens, the greatest danger to the culture is caused by such pathogens as American powdery mildew, anthracnose and septoria. Previously unknown as a pathogen of black currant, since the 1980s, American powdery mildew has been widespread everywhere. In the Khabarovsk Territory, in years with favorable conditions for the pathogen, the intensity of the development of the spherotheca reaches 60-75%. The increasing harmfulness of anthracnose and septoria was revealed. The intensity of their development on crop plantings reaches 50-60%. Such phytophages and phytopathogens as currant bud moth, leaf beetles, gooseberry fireworm, yellow blackcurrant sawfly, narrow-bodied green (currant) gold leaf, flanked and columnar rust were not detected during the research period on crop plantings. Although back in the 60-70s. the last century caused significant damage to black currant plants.

Mite Pests of Southern Highbush Blueberry in Florida

Several mite species attack southern highbush blueberries (SHB), including the southern red mite (Oligonychus ilicis McGregor (Acari: Tetranychidae)), the false spider mite or flat mite (Brevipalpus yothersi Baker) and the blueberry bud mite (Acalitus vaccinii Keifer). The southern red mite is the key mite pest attacking blueberry plants in the southeastern US (Lopez and Liburd 2020). The false spider mite is a secondary leaf feeding mite pest that was reported attacking southern highbush blueberry in 2016 (Akyazi et al. 2017). This publication discusses southern red mites and flat mites on SHB in Florida, including life cycle, damage, and management practices.

Molecular phylogenetic analyses reveal a deep dichotomy in the conifer-inhabiting genus Trisetacus (Eriophyoidea: Nalepellidae), with the two lineages differing in their female genital morphology and host associations.

We analyzed the phylogenetic relationships of the genus Trisetacus using two genes [cytochrome c oxidase subunit I (COI) and D1-D2 region of 28S rDNA (D1-D2 28S)], a representive taxon sampling (nearly 40% of known diversity), and a large set of close and distant outgroups. Our analyses suggest the presence of a dichotomy between Trisetacus associated with Cupressaceae and Pinaceae. The following smaller molecular clades were found: Pin-1 (bud mites, twig sheath mites, bark gall mites, and endoparasitic mites from pinaceans), Pin-2 (needle sheath mites from pines), Pin-2a (putative Nearctic group of needle sheath mites), Pin-2b (putative Palearctic group of needle sheath mites), Cup-1 and 2 (bud, cone, seed mites and mites living under bark scales from cupressaceans). The monophyly of the recently proposed subgenus Brevithecus nested within clade Cup-2 was confirmed. Ancestral character reconstruction analyses recovered: (1) Pinaceae as the ancestral hosts of Nalepellidae and Trisetacus, (2) repetitive reductions of the spermathecal tube independently occurred in two lineages of Trisetacus from Cupressaceae, and (3) several mite habitats on host (galls, cones, twig sheaths, seeds, inside leaves, and under scales) are evolutionarily derived states, whereas living in buds or needle sheaths are ancestral states for Trisetacus clades Cup and Pin. Using confocal microscopy, we identified six basic types of the female internal genitalia of Trisetacus based on shapes of the spermatheca and spermathecal tube. These genitalic types are strongly correlated with lineages recovered by molecular phylogenetic analyses, suggesting that the female genital morphology is both evolutionarily conserved and is a factor influencing macroevolutionary patterns in this group of mites.