Examining the Response of Various Ornamental Plants to Meloidogyne javanica and investigating the Synergistic Impact of Neocosmospora solani on Nematode Infestation in Ferocactus

Root-knot nematodes (Meloidogyne spp.) are amongst the most important plant-parasitic nematodes. These nematodes, which bind the roots of sensitive plants, are obligate parasites of plants. Numerous pathogens, including nematodes, fungi, bacteria, and viruses, cause damage to ornamental plants. Damage caused by these pathogens includes crown and root rots, cankers, and leaf blotches, among others. Given the importance of ornamental plant production and the detrimental effects inflicted by root-knot nematodes and root rot fungi on these plants, the current investigation aimed to assess the response of nine ornamental plants to the nematode Meloidogyne javanica. Additionally, the study sought to determine whether Neocosmospora solani, in conjunction with the nematode, could induce a synergistic effect on Ferocactus.

The response of nine ornamental plants to the root-knot nematode was examined in the present study. Upon isolation from the crowns and roots of different cacti varieties grown in greenhouses containing ornamental plants in Ardabil province, the rot fungus was determined to be Neocosmospora solani. The M. javanica population was cultivated in the Plant Pathology Laboratory of Azarbaijan Shahid Madani University. A suspension of M. javanica eggs and larvae was utilized to inoculate ornamental plants with nematodes. To assess the plants' response to the nematode, several plant growth factors and the quantity of knots on the roots were examined. The present study also assessed the synergistic impacts of two nematode and fungal pathogens on specific growth factors of Ferocactus. Both simultaneous and non-simultaneous inoculation techniques were utilized.

Among the plants with knots on the roots, except for tiger Aloe, in the rest of the investigated plants, there were significant differences among the treatments. Based on the comparisons between plants inoculated with nematodes, the highest number of knots was observed on the roots of Begonia plants and the lowest in Echeveria, Ferocactus and Tiger aloe. Notably, Tradescantia spathace was excluded from the analyses as a result of significant nematode damage and subsequent plant mortality. Based on the absence of any damage observed on the shoots and roots of the control plants of this species, it can be categorized as one of the Meloidogyne-sensitive plants. The growth factors examined in plants were similarly impacted in the majority of the plants that sustained significant damage, with begonia plants exhibiting the most pronounced effect. We observed the presence of diminutive, pallid flowers as well as a reduction in the mass of the roots and aerial components in the spotted begonia. Notwithstanding a minor aberration in the morphology of certain roots and aerial organs, no knots of significance were detected in Myrtillocactus. There were no discernible differences in plant growth factors between the control and inoculated plants; therefore, this particular plant can be deemed the most resistant to Meloidogyne among all the plants that were examined. Given that this plant is frequently utilized as a basal component in grafted cacti, this result may prove to be extremely beneficial. In relation to the synergistic assays conducted on the Ferocactus plant, the outcomes of both approaches demonstrated statistically significant differences among the treatments as determined by variance analysis for all the characteristics under investigation, namely shoot length, shoot weight, root length, and root weight. The treatments were inoculated with nematodes, and the control group exhibited the greatest shoot length. These treatments exhibited the shortest shoot lengths when inoculated with nematodes and fungi. The treatments containing nematode and fungus resulted in the shortest root length and weight, while the control plants devoid of nematode and fungus exhibited the greatest root length and weight.

Overall, the findings of the current study demonstrated that root-knot nematodes have a significant capacity to inflict damage upon the ornamental plants under investigation. However, it was also confirmed that M. javanica and N. solani have synergistic effects on Ferocactus plant damage. The results validate the importance of promptly detecting and managing these organisms within greenhouse environments where ornamental plants are cultivated. Therefore, before the beginning of the infection and with the early detection of these diseases, it is possible to prevent the spread and damage caused by the root-knot nematode and root rot fungus in ornamental plants by using integrated management.