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Phytophthora species have long been reported to cause Phytophthora disease in citrus with symptoms of gummosis, root rot and fruit brown rot. Due to the lack of an up‐to‐date investigation of Phytophthora species currently causing the disease in Northern Vietnam, this study aimed to determine the current Phytophthora species associated with the disease in this region. An extensive collection of diseased samples was conducted in the main citrus‐growing areas in Northern Vietnam from 2021 to 2022. Fifty‐four Phytophthora isolates were obtained and initially divided into four groups based on morphological characteristics, including colony morphology, mycelial growth rate and reproductive structures. Representative Phytophthora isolates from each group were then identified as P. palmivora, P. nicotianae, P. citrophthora and P. mekongensis based on the phylogenetic analysis of ITS and cox1 gene sequences. Pathogenicity tests showed that these four Phytophthora species induce gummosis and brown rot on pomelo, orange and lime, with pomelo being the most susceptible, followed by orange and lime, respectively. Koch's postulates were confirmed. All the Phytophthora species were sensitive to various fungicides including mancozeb, metalaxyl, chlorothalonil, fosetyl aluminium, potassium phosphonate and dimethomorph, of which metalaxyl was the most potent inhibitor of colony growth. Our findings provide updated information on the current Phytophthora species associated with gummosis in citrus in Northern Vietnam, with P. mekongensis being recorded for the first time in this region. This will serve as a reference for Phytophthora studies on citrus in the future and for developing an integrated management strategy for Phytophthora disease.

The excessive use of pesticides is a problem in most parts of the world today because of their broad and unspecific target range that is considerably harmful. The accumulation of several chemical insecticide residues based on chlorpyrifos-methyl, organochlorine, different isomers of HCH, DDT etc., in Triticum aestivum L. plants can be dangerous. Hence, there is an urgent need to develop potential and safer alternative measures. Wheat (Triticum aestivum L.) is a major cereal crop grown and used for food, animal feed, beverages and furniture accessories in most parts of the world. It also serves as a host to various insect pests. Our previous studies showed the insecticidal potency and specificity of short ssDNA oligonucleotides from the inhibitor of apoptosis (IAP-2 and IAP-3) genes of Lymantria dispar multicapsid nuclear polyhedrosis virus (LdMNPV) against gypsy moth (L. dispar) larvae, a possible insect pest of non-host plants like wheat. Consequently, the present study analyzes the effects of ssDNA oligonucleotides used as DNA insecticides on wheat (T. aestivum) plant biomass, plant organs and some biochemical parameters as a marker of the safety margin on non-target organisms. The results obtained on plant biomass showed that groups treated with ssDNA oligonucleotides at concentrations of 0.01 pmol • µl −1 , 0.1 pmol • µl −1 and 1 pmol • µl −1 varied in comparison with the control group, but remained harmless to plant growth and development, while the treatment concentration of 0.001 pmol • µl −1 did not affect the plant biomass. The glucose, protein and phosphorous biochemical parameters, analyzed after 21 days, showed that the ssDNA oligonucleotides used were equally safe. The data obtained for the plant organs (leaves and root lengths) indicate that the phenomenon of DNA insecticides can be further studied and developed for plant protection while improving the growth of plant organs even for a non-target organism such as wheat T. aestivum plants.

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При перепечатке любых материалов ссылка на журнал «Теоретические и прикладные проблемы агропромышленного комплекса» обязательна. Журнал зарегистрирован Федеральной службой по надзору в сфере связи и массовых коммуникаций. Свидетельство о регистрации СМИ ПИ ФС77-35867 от 31 марта 2009 года.