Xanthomonas citri subsp. citri, a causative agent of the citrus canker (CC) disease, belongs to one of the essential groups of the bacterial phytopathogen family, Xanthomonadaceae. It has been a potential threat to the globally significant citrus fruit crop, which has remained under investigation for disease management and epidemiology since the 1980s. In Pakistan, the average yield of citrus is 11 t/ha, which is lower than other countries, including China, Brazil, and India, having average productions of 27, 26, and 22 tons/hectare, respectively. Citrus canker is one of the most devastating diseases, posing a significant threat to crop yield and fruit quality. To date, five distinct types (or forms) of the citrus canker have been recognized; the Asiatic (Canker A) form is most destructive and affects most citrus cultivars. Severe infection outcomes include dieback, defoliation, severely blemished fruit, premature fruit drop, and reduced fruit quality. The infection increases under humid, warm, cloudy climate, wind, and heavy rainfall. The analysis of plasmid and chromosomal DNA of X. citri subsp. citri depicted an evolutionary relationship among pathovars of Xanthomonas. The extensive study on the genome of X. citri subsp. citri has contributed to the current knowledge of plant host recognition of pathogens, host specificities, dissemination, and propagation. Regulatory programs, i.e., quarantine or exclusion, continued to be practiced, prohibiting infected citrus plant material into the existing stock. Other measures include removal of inoculums sources, resistant hosts, protective copper-containing sprays, and windbreak systems. In this review, we explored the latest trends in the areas of epidemiology, pathogenome, detection, host–pathogen interaction, biofilm formation, and management of X. citri subsp. citri.
Mango sudden death (MSD) or quick decline (QD) is the most destructive disease found in mango orchards of Pakistan and is characterized by collapse of the vascular system by Ceratocystis fimbriata and Lasiodiplodia theobromae. Cultural practices, chemicals, and biological control are the most valuable tools for the management of MSD, but the role of micronutrient deficiencies has remained an area that is heavily ignored by the farming community. To study the impact of micronutrients, four mango orchards were selected at different locations where different combinations of micronutrients, i.e., Zinc (Zn), Boran (B), and Copper (Cu) in the form of Zinc sulphate (ZnSO4), Borax/Boric acid (H3BO3), and Copper Sulphate (CuSO4), were applied both foliar and in drench along with the recommended doses of Nitrogen: Phosphorous: Potassium (NPK), and Farmyard manure (FYM), respectively. The quantities of micronutrients were determined from the soil and leaves before and after application of the treatments. The impact of micronutrients was measured in terms of reduction in disease severity and increase in fruit yield. The results revealed that the application of all three micronutrients both in soil drench and in foliar form significantly decreased the disease severity at three locations and increased the yield in all four mango orchards. Application of ZnSO4 (0.8%), +H3BO3 (0.8%), +CuSO4 (0.5%) and as soil drench ZnSO4 (400 g) + Borax (200 g) + CuSO4 200 g plant−1 proved to be the best treatments, with an average of 12.88 and 14.03% reduction in disease severity and with an average yield of 128 and 119 kg, respectively. The application of micronutrients would be a promising solution in an integrated disease management program used to tackle MSD.
R ice (Oryza sativa L.) is one of the most important and widely cultivated cereal crops all over the world (Salim et al., 2003). The tropical and subtropical areas of the world are the major rice producer while 90% of the total rice production is occurring in Asian countries (Ezuka and Kaku, 2000). Heavy losses due to rice pests and diseases are the major constraints in world rice production. This important crop badly suffers from more than forty different microbial disease and disorders. Among them, bacterial leaf blight of rice (BLB) caused by Xanthomonas oryzae pv. oryzae (Swings et al., 1990) is a serious threat for irrigated, deep water, rainfed, temperate, tropical and subtropical rice growing areas of the world (Mew, 1987). This destructive disease has now become a serious pathosystem to rice crop especially in South East Abstract | Bacterial leaf blight is a devastating disease of paddy rice crop throughout the rice growing countries. Several commonly available plant decoctions were investigated as the bioactive eco-friendly compounds, and as the possible alternatives to hazardous chemicals for the control of BLB of rice. Aqueous extracts of fifteen different plant parts either individually or in combination were tested at various concentrations under in vitro conditions by poison food and disk diffusion techniques while best effective seven were trialed in glass house and field experiments to determine their efficacy against Xanthomonas oryzae pv. oryzae. In vitro and in vivo studies under different conditions showed significant response of Mentha piperita, Azadirachta indica and Aloe vera either tested individually or in combination of two or more than two decoctions against the bacterium in question. When used individually, M. piperita demonstrated best in vitro, field and glass house experiments followed by the A. indica which also proved its efficacy against the pathogen. The combination of M. piperita, A. indica and C. limon was superior in reducing the BLB of rice. Besides this, all treatments showed significant effect on the agronomic traits of rice plants. The reduction of disease in all the trials along with healthy crop stand in glass house and field indicated that these decoctions might play an important role in biological management strategies for the control of BLB of rice. The present research may provide an avenue for the formulation of new bactericides for future uses.
Huanglongbing (HLB), also known as citrus greening disease, is the most devastating disease of citrus across the world, caused by the phloem limited fastidious bacterium ‘Candidatus Liberibacter spp.’. This research was conducted on HLB infected 10-year-old Kinnow orchard located at Multan, Pakistan. Different classes of antibiotics in various combinations were applied on HLB-infected trees. The antibiotic treatments were applied before flowering in February, during fruit setting in April and at fruit growth stage in June. The different antibiotics combinations used were Ampicillin sodium + Rifampicin, Cefalexin + Rifampicin, Ampicillin sodium + Cefalexin, Ampicillin sodium + Cefalexin + Rifampicin and Control (distilled water). Different fruit qualitative and quantitative attributes were examined. The application of antibiotics significantly decreased 2–11% in flower, June and pre-harvest drops as compared to control. Further, antibiotics increased fruit weight and yield by five times while the juice content, total soluble solids, ripening index, total sugars, phenolic and vitamin C content were also increased in fruits. In addition, total soluble proteins, peroxidase and catalase activities were increased in fruits harvested from antibiotic treated plants compared to control, however the superoxidase dismutase activity was decreased in fruits of antibiotic treated plants. Finally, it is concluded that application of different antibiotics combinations helps in improving the fruit yield and different quality attributes of HLB infected Kinnow trees.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
customersupport@researchsolutions.com
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.