Walnut (Juglans regia L.) is a significant nut crop in the southern regions of Kazakhstan; however, its productivity is substantially limited by fungal and bacterial diseases. Therefore, a phytopathological investigation was conducted in 2023–2024 in the Almaty and Turkestan regions, including field monitoring, pathogen isolation, molecular identification, and pathogenicity testing. Field monitoring revealed that symptoms of brown spot, walnut canker, walnut blight, bacterial blight, and crown gall were widespread. The overall disease incidence ranged from 8% to 30%, while the disease severity index varied from 15% to 70% across the surveyed sites. Pure cultures of pathogens were isolated from 69 samples, and their morphology was characterized. Molecular identification through sequencing of universal genetic loci (the internal transcribed spacer for fungi and 16S ribosomal RNA for bacteria) revealed the presence of the fungal species Alternaria alternata and Fusarium incarnatum, as well as the bacterial species Pantoea agglomerans and Xanthomonas arboricola pv. juglandis. Pathogenicity testing confirmed the virulence of the identified pathogens, which induced characteristic symptoms of brown spot, walnut canker, and walnut blight, consistent with those observed in the field. These findings have considerable practical significance for improving phytosanitary monitoring and protection systems in walnut plantations, thereby facilitating disease outbreak prediction and the development of effective quarantine measures.

Walnut blight is a harmful disease that affects nut crops. It is caused by the bacterium Pantoea agglomerans and has become widespread in recent years, posing a serious threat to walnut plantations. The disease not only destroys more than half of the crop, but also causes bark cracking and slow crown desiccation, which can lead to further infections. One of the most important requirements for modern varieties of agricultural plants, including nut crops, is an increased level of resistance to diseases. In Kazakhstan, there is currently no data on the spread of diseases of nut crops and resistance of varieties to harmful diseases. This makes it difficult to recommend a suitable variety for industrial and private nut orchards. Ipmroving the breeding process and increasing the productivity of walnut plantations, it is extremely relevant to assess the resistance of varieties to the most dangerous pathogens. For the first time in Kazakhstan, a two-year monitoring study was conducted to assess the resistance of promising walnut varieties and forms to the Pantoea agglomerans, taking into account the prevailing weather and climatic conditions. The study was carried out on 23 varieties and forms in the main fruit-growing regions of the country. It was found that the walnut blight caused by the bacterium Pantoea agglomerans annually damages walnut plants, and the degree of disease damage depends on the prevailing weather and climatic conditions. The research results revealed that the Moldavian variety - Kazaku showed high resistance to walnut blight. Other resistant varieties are Miroslava, Ovidiu, Germisara, Yarivski, Peshanski, Kogylnichanu, 185, Lipin 2, Liaohe, Fernor, Plin, and Kishinevski. These varieties showed minimal damage, not exceeding 2 points, during the years of observation. These varieties are recommended as suitable varieties for increasing the productivity of industrial and private nut orchards and improving the breeding process.

В мировой практике клональное микроразмножение земляники садовой применяется для быстрого и эффективного размножения отдельных форм и сортов из небольшого количества исходного материала, отбора in vitro на ранних стадиях развития. На стадии введения в культуру тканей растения земляники стерилизовались препаратами активный хлор в составе гипохлорита натрия в различных концентрациях и экспозиции. Для развития регенерации и приобретение экологически чистой рассады земляники в питательную среду вводили в обмен регуляторов роста химической природы (цитокинины и ауксины) аминокислоту пролин в концентрации 10мг/л, аденозинтрифосфат (АТФ) -10мг\л, и витамин С-аскорбиновая кислота – 10мг\л. Установлено, что внесение аскорбиновой кислоты в концентрации 10 мг/л в состав питательной среды полностью исключает фенольное окисление апексов на этапе введения в культуру тканей и регенерации. Внесение аминокислоты пролин и АТФ в состав питательной среды увеличило регенерацию на 10-15% по трем сортам земляники. На этапе укоренения большое количество корней образовывалось на сорте Мальвина. У сортов Сабрина и Ред Гонтлит эти данные были несколько ниже. По высоте растений выделялся сорт Мальвина 10 шт. Наименьшей высотой растений характеризовались сорта Сабрина и Ред Гонтлит 5 и 7 шт. соответственно. Укорененные микрорастения земляники пересаживались в условия ex vitro для их адаптации.

The most widespread and effective method of protecting walnut trees from diseases is through chemical treatments. With the increasing variety of fungal pathogens affecting walnut trees in the southern zone of fruit production in Kazakhstan, there is a need to study the effectiveness of fungicides against these pathogens. Therefore, laboratory and field studies were carried out to evaluate the effectiveness of several fungicides against the most common diseases of walnut trees caused by Fusarium and Alternaria fungi. The effectiveness of fungicides with different mechanisms of action was studied for the first time. The fungicides evaluated were Score (difenoconazole, 250 g/l), Horus (cyprodinil, 750 g/kg), Stroby (kresoxim-methyl, 500 g/kg), Luna Tranquility (fluopyram, 125 g/l + pyrimethanil, 375 g/l) against walnut diseases in the southern zone of fruit cultivation in Kazakhstan. The results of both laboratory and field experiments showed that the most effective fungicide against fungal pathogens on walnut was Score (difenoconazole, 250 g/l). Stroby (kresoxim-methyl, 500 g/kg) also demonstrated over 80% biological efficacy against Alternaria alternata. The results of this study will assist local growers in managing various fungal diseases in walnut plantations.

Современное садоводство требует саженцы с низким ростом и компактностью крон, безвирусные и высококачественные, что обеспечивает интенсивность и высокую продуктивность сада. В системе производства безвирусного посадочного материала методу клонального микроразмножения отводится значительное место. Использование биотехнологических методов в питомниководстве позволяет повысить эффективность оздоровления растений до 100%, в 5-10 раз и более увеличить коэффициент размножения и на 2-3 года ускорить внедрение новых оздоровленных сортов и форм в производство. В представленных исследованиях определён состав вирусных болезней в маточных насаждениях подвоев яблони и оптимизированы этапы клонального микроразмножения с модификацией состава питательной среды на этапах регенерации апексов после введения в культуру тканей, пролиферации и ризогенеза, а также их адаптации к условиям ex vitro. Проведена диагностика и идентификация сокопереносимых вирусов ACLSV и ASGV методом биологического тестирования. Для исключения вирусных инфекции из растений в условиях защищенного грунта проведена термотерапия при температуре ≈38°С и влажностью ≈60-70% продолжительностью 30 дней. Из активно отросших верхушечных побегов в условия in vitro введена меристематическая ткань. В результате работы в контейнерной культуре при черенковании безвирусных пребазисных маточных растений получено 126 базовых растений подвоя Арм 18 и 31 базовых растений подвоя Жетысу 5.

The walnut (Juglans regia L.) is an economically important crop in southern Kazakhstan, where brown spot disease, caused by the fungus Alternaria alternata, poses a serious threat to yield. The objective of this study was to determine whether A. alternata isolates obtained from walnut leaves in orchards located in different climatic zones (Almaty and Turkestan regions) exhibit pathogenic properties in all cases. The fungus was identified based on morphological characteristics and confirmed by PCR analysis. Pathogenicity was assessed through artificial inoculation of walnut leaves under controlled conditions. The results demonstrated that A. alternata exhibits pathogenicity under diverse climatic conditions, inducing brown spot symptoms, including chlorosis and necrosis of leaves. These findings confirm the wide distribution and threat of brown spot and provide a scientific basis for further research aimed at developing effective plant protection strategies.