Corn stunt disease caused an epiphytotic outbreak in maize production in Argentina, resulting in yield losses of up to 30
Sericulture in India is a centuries-old tradition that supports the livelihood of marginal and rural communities. Silk production is intricately linked to the health of silkworms and their host plants. Among the major challenges in cocoon production are diseases that affect both the silkworms and their host plants. The nutritional and physiological well-being of silkworms is highly dependent on the quality of the foliage they consume. Diseases and pest infestations in host plants not only reduce the quantity and quality of available leaves but also indirectly affect silk quality and cocoon yield. Host plants such as Persea bombycina, Ricinus communis, Terminalia tomentosa, Terminalia arjuna, and Morus spp. used in silkworm rearing are particularly vulnerable due to their tender, nutrient-rich leaves and broad leaf surfaces that attract various pathogens. In this review, we have compiled the obligatory relationship between silkworms and their host plants. It focuses on major diseases affecting these plants, supported by relevant case studies. This review also comprised the integrated disease management (IDM) strategies to ensure healthy host plants and improve silk productivity. Furthermore, it emphasizes integrated IDM strategies, including cultural and genetic practices, chemical treatments, and biological control methods to safeguard host plant health. To ensure sustainable sericulture, especially in terms of silkworm host plant diseases, the adoption of improved technologies and integrated disease management practices is essential. Achieving this goal requires coordinated efforts from government agencies, researchers, and farming communities to effectively tackle plant health challenges and meet industry demands.
Basal stem rot (BSR), caused by Ganoderma orbiforme (syn. G. boninense), is among the most economically devastating diseases of oil palm, with yield losses reaching 80
Rhizoctonia solani Kühn is a soil-based basidiomycete causing black scurf, a major disease affecting potato production worldwide due to reduced tuber quality and market value. This pathogen comprises genetically distinct anastomosis groups (AGs) based on hyphal fusion compatibility, with different AGs exhibiting varying virulence and host specificity. Although potato cultivation in Guatemala's western highlands is economically significant, the AG composition of R. solani populations has not previously been characterized. In this study, 138 R. solani isolates were obtained from tubers of Loman variety showing black scurf symptoms in three departments: Huehuetenango (n = 44), San Marcos (n = 48), and Quetzaltenango (n = 46). Molecular identification using AG-specific primers, targeting the rDNA-ITS, region revealed three AGs: AG-3 PT was most common (63.77
Leaf scald disease (LSD), caused by Xanthomonas albilineans, and ratoon stunting disease (RSD), caused by Leifsonia xyli subsp. xyli, are two major diseases of sugarcane in Brazil. Lab-diagnostic tests and resistant cultivars are the effective strategies to control both diseases. The dot blot immunoassay (DBI) is the diagnostic technology for both, which stresses the need to accurately identify each disease. The adequate sugarcane for DBI to provide trustful results also needs clarification. Moreover, DBI has the potential for ranking sugarcane genotypes based on difference of bacterial population the technology provides. Therefore, this work aimed to examine the usefulness of DBI to distinguish LSD from RSD, the adequate cane age of sampling and to establish a protocol for ranking sugarcane genotype to LSD. For the first objective, sugarcane fields with distinct phytosanitary status were submitted to DBI; for plant age, contaminated saps from 8-, 9-, and 10-month-old canes were tested for LSD by DBI; for genotype ranking, the spread and pathogen population density were examined across cultivars. Assays were carried out under completely randomized block design with ten replications per treatment; each replication with one plant per vase; the experiment was repeated. The data showed DBI robustness since each antibody could identify negative samples from diseased positive samples; DBI permitted detection of both diseases in the same sample but also single ones. Ten-month cane is the appropriate age for testing LSD by DBI. As for genotype resistance to LSD, cultivar RB966928 was the most susceptible and cv. RB867515, the most resistant.
Cassava brown streak disease (CBSD) remains a major constraint to cassava production in East Africa, with planting date and site conditions strongly influencing yield outcomes. In Tanzania, farmers typically plant cassava twice a year: March–April (primary season) in the long rainy season and November–December (secondary season) during the short rainy season. To explore the benefit of extended planting dates, we evaluated root production of three cassava varieties: CBSD-tolerant Kiroba and CBSD-susceptible Albert and Mkombozi across extended planting windows (October–May) at two contrasting sites: Chambezi (coastal agroecology, high CBSD pressure) and Ukiriguru (inland mid-altitude agroecology (Lake Zone), low CBSD pressure). Using virus-free planting material, Kiroba was tested at both sites, Albert only at Chambezi, and Mkombozi only at Ukiriguru. Therefore, genotype × site comparisons are limited to Kiroba, and Albert and Mkombozi results were interpreted as site-specific responses. Taking all varieties together, average yields were 28.1 t/ha at Chambezi and 7.5 t/ha at Ukiriguru. At Chambezi, soil moisture was generally sufficient across all six planting dates, but CBSD incidence rendered most of Albert’s October–December harvests unusable, while Kiroba remained unaffected. In contrast, yields at Ukiriguru were primarily determined by soil moisture, with effective root production restricted to October–December plantings. Bemisia tabaci abundance was similar at both sites, but disease progression correlated with vector presence only at Chambezi. These findings show that planting date is critical for CBSD-susceptible varieties under high disease pressure, whereas tolerant varieties are less constrained. In low-pressure zones, soil moisture availability is the dominant yield determining factor. Extending cassava planting windows can enhance productivity, but success depends on deploying CBSD-tolerant varieties, isolating susceptible farmer-preferred types from inoculum sources, and making use of clean planting material. The results further indicate that successful crop production can be achieved for plantings within a 6-month plant range coastal Tanzania, while the range in the Lake Zone is only 3 months. Results also highlight critical phases when adequate watering must be applied, guiding farmers to prioritize adequate watering during the establishment phase (first 4–6 weeks after planting), when cassava is most vulnerable to moisture stress. Overall, these insights provide practical strategies for improving cassava productivity and advancing sustainable crop cultivation.
To explore the effects of different altitudes and crop cycle on the occurrence of sugarcane smut in the low-latitude plateau region of Yunnan, this study conducted a systematic investigation of smut incidence in the southern subtropical humid, southern subtropical semi-humid, and northern tropical semi-humid sugarcane growing areas of Yunnan. The results showed that there were significant differences in smut incidence among different regions, altitudes, and crop cycle in Yunnan. The smut incidence ranged from 4.94% to 16.44% across different regions, indicating that smut has occurred universally and caused severe damage in Yunnan. The incidence varied from 2.89% to 14.71% across different altitudes, exhibiting a decreasing trend with increasing altitude. For different crop cycle, the incidence ranged from 5.81% to 15.31%, showing an increasing trend as the crop cycle extended. Under the ecological conditions of Yunnan's low-latitude plateau, altitude and crop cycle were identified as the main sources of variation in smut incidence. Their interaction effect was not significant, whereas the respective main effects of both factors were statistically significant. Meanwhile, the contribution rate of variation to smut incidence of altitude (63.20%) was higher than that of crop cycle (28.81%). These findings provide a scientific basis for the rational distribution of elite sugarcane varieties and the scientific control of smut in the low-latitude plateau sugarcane regions of Yunnan.
“Candidatus Liberibacter solanacearum” (Lso) is a phloem-limited bacterial pathogen transmitted by psyllid. In the USA, the haplotypes A and B are transmitted by the tomato psyllid, Bactericera cockerelli, and are responsible for economic damage to the solanaceous crop industry. In tomato, haplotypes A and B cause diseases with differing degrees of severity, yet their underlying mechanisms are not well understood. The role that abiotic stress plays in disease development has not been characterized. In the present study, we evaluated whether water stress influenced the development of symptoms associated with these haplotypes in tomato (Solanum lycopersicum “Moneymaker”). First, pot-grown tomato plants were subjected to either a control or a water-stress regime, then they were assigned to one of three infection treatments (Lso-free, LsoA, or LsoB) under laboratory-controlled conditions. Symptom development was monitored for up to 8 weeks following infection. Results of this experiment revealed that water stress significantly reduced the plant water potential and was the primary driver of reduced height, with infection only having an effect in later weeks. Water stress also increased the detectability of Lso throughout the plant and across three timepoints (weeks 4, 6, and 8 after infection). This increase in Lso-positive tissues suggests that water stress creates a more homogenous distribution of Lso throughout the plant. More noticeably, water stress significantly reduced the severity of the disease associated with haplotype A but not B. Overall, these findings revealed the existence of haplotype-specific interactions between Lso infection and water stress on the tomato health. This work highlights the influence of abiotic factors on plant health.
Strawberries are susceptible to several diseases, including soft rot, which is often caused by Rhizopus species. Accurate identification of the causal agents and the identification of effective treatments to mitigate this problem are important for the sustainability of strawberry production during postharvest. This study aimed to identify two isolates of Rhizopus responsible for soft rot in strawberries, as well as to evaluate the efficacy of commercial fungicides and biological products in the preventive control of the disease. Two separate experiments were conducted per isolate: one using wounded fruit inoculated with a spore suspension in water, and another using nonwounded fruit inoculated with a suspension containing strawberry juice, simulating contamination during commercialization when juice from damaged fruit contacts the surface of others. The two isolates were identified as Rhizopus stolonifer and R. koreanus. Biological products, in general, did not significantly reduce disease incidence, but Serenade reduced the risk of R. stolonifer causing disease when inoculation was performed without wound with juice. The fungicide fludioxonil provided 100
Potato common scab (Streptomyces sp.) is an economically important disease that reduces the quality and market value of tubers. A key aspect in developing management strategies involves accurately quantifying the disease. Due to the three-dimensional nature of the tuber and the heterogeneous distribution of lesions across its surface, visual estimates of severity can be challenging. Therefore, the objectives of this study were to develop and validate a standard area diagram (SAD) for estimating common scab severity on potato tubers and to compare validation outcomes obtained using real tubers and digital images. A SAD comprising six severity levels (from 1.3 to 66.8
Banana Bunchy Top Virus (BBTV) represents the most devastating viral threat to banana production in Sub-Saharan Africa, where over 100 million people depend on bananas as their primary staple food. The virus’s recent eastward expansion into Tanzania in 2020 has created an unprecedented agricultural crisis, with complete yield losses documented in affected areas. This review synthesizes current knowledge of BBTV’s impact across Sub-Saharan Africa, with particular emphasis on Tanzania’s experience as a case study in disease emergence and response. We examine the integration of cutting-edge diagnostic technologies, including AI-powered surveillance and molecular detection platforms, with traditional management approaches. The analysis reveals critical gaps in sustainable disease management. It highlights the urgent need for multi-faceted strategies that combine technological innovation with community-based interventions to protect food security for millions of smallholder farmers.
A study was conducted to investigate the potential alternative hosts of the wheat blast pathogen, Magnaporthe oryzae pathotype Triticum (MoT), among different cereals and weed species prevailing in farmers’ fields in Bangladesh. M. oryzae was detected on the leaves/heads/panicles of some winter cereals such as rice (Oryza sativa), triticale (xTriticosecale), barley (Hordeum vulgare), foxtail millet (Setaria italica), and durum wheat (Triticum durum), as well as four weed species: goose grass (Eleusine indica), crab grass (Digitaria sanguinalis), torpedo grass (Panicum repens), and basket grass (Oplismenus burmannii). The extracted isolates were tested with the MoT-specific marker MoT3 and, together with pathogenicity assays on susceptible wheat, confirmed that isolates from wheat, triticale, barley, and durum were MoT. Thereafter, a cross-infection experiment was conducted under controlled conditions using the isolated M. oryzae isolates to inoculate potential alternative hosts to investigate the host spectrum of MoT and other pathotypes. MoT was able to infect and produce blast symptoms on leaves of triticale, barley, and durum, and the isolates from these three crops could infect wheat as well, implying that the four crops share the same blast pathotype MoT. It is noteworthy that MoT was also able to infect the weed species goose grass, producing minor blast symptoms; in contrast, the isolates from goose grass could not produce any symptoms on wheat leaves. Apart from the above-mentioned isolates, no other studied isolates could produce any symptoms on wheat leaves. The fact that MoT is able to infect goose grass makes this grass species a potential alternative host of MoT in the off season.
Banana bunchy top virus (BBTV, Babuvirus musae) is one of the most damaging viral threats to banana production, yet frontline diagnostics rely on PCR, ELISA or proprietary assays that are poorly suited to low resource deployment or associated with high per test cost. We developed a recombinase polymerase amplification (RPA)-Cas12a assay that achieves high sensitivity using crude extracts with fluorescence or lateral flow readouts. Using RPA primers to BBTV DNA-R gene and a Cas12a crRNA targeting a conserved site, we developed the first CRISPR-based diagnostic assay for BBTV. The assay was configured in a one-tube workflow in which the RPA and Cas12a components are separated until amplification is complete, reducing contamination risk. With a DNA-R gBlock standard, the one-tube assay achieved a limit of detection of 5.11 aM ( 3 copies/µl) in both formats, which is around 250-fold more sensitive than a commercially available fluorescence RPA and about fourfold more sensitive than an available RPA-based lateral flow. The RPA-Cas12a assay reliably detected BBTV in both fresh and dried leaf material, across isolates from both genetic subgroups, and showed no cross-reactivity with common banana viruses. A two-step high sensitivity workflow further reduced the limit of detection to near single copy levels. This work establishes a generic RPA-Cas12a framework for plant virus diagnostics and an immediately deployable assay for BBTV surveillance, eradication and clean planting material programmes.
Huanglongbing (HLB) disease is now endemic to Florida (USA), and the citrus industry there must adapt to persistent high disease pressure. The disease is associated with the phloem-limited bacterium Candidatus Liberibacter asiaticus and transmitted by the insect vector Diaphorina citri. Several techniques have been developed to manage various aspects of HLB, but no single technique can effectively control the disease on its own. Because there is no “silver bullet” for HLB, the available tools must be integrated into regional integrated pest management (IPM) strategies and further developed in order to achieve disease control and maintain sustainable citrus production in the state. The intent of this report is to highlight the tools available for HLB IPM, particularly those developed by our research team and industry partners. This includes the use of individual protective covers (IPCs) and plant defense inducers as preventive methods to protect young trees and new flush and oxytetracycline (OTC) trunk injection on mature trees to manage HLB under endemic conditions. Additional tools in the developmental pipeline, including an automated delivery system for OTC trunk injections, which could help reduce labor costs, are also discussed. Together, these integrated approaches provide a practical framework for mitigating HLB impacts while supporting the long-term resilience and productivity of Florida’s citrus industry.
Sugarcane yellow leaf virus (SCYLV) occurs in all sugarcane producing regions of the world and can reduce yield up to 50
Fusarium wilt of banana (FWB) is a major agricultural threat worldwide, historically attributed to several races of Fusarium oxysporum f. sp. cubense (Foc). The updated taxonomic scheme tends to group these races of Foc into distinct species. In addition to the F. oxysporum species complex (FOSC), a few species within the Fusarium fujikuroi species complex (FFSC) have occasionally been reported on bananas. In eastern Democratic Republic of Congo, FWB has been reported across North and South Kivu. This study aims to assess the diversity of Fusarium locally associated with FWB through morphological, phylogenetic, and pathogenic characterization. Seventy Fusarium strains were isolated from pseudostems showing infection of vascular tissues. Morphological characterization was performed on synthetic low-nutrient agar, potato dextrose agar, and carnation leaf agar. Pathogenicity was assessed on Cavendish and Gros-Michel in greenhouse conditions. Molecular phylogenetic relationships were inferred based on DNA sequence data from partial translation elongation factor 1-alpha and the second-largest subunit of RNA polymerase. To confirm species identity, partial calmodulin and beta-tubulin gene regions were also sequenced for some strains. Of the 70 Fusarium strains analyzed, 31 belonged to the FOSC, including 28 strains identified as F. tardichlamydosporum and one strain (F141) identified as F. duoseptatum, both previously recognized as Foc Race 1. Two additional FOSC strains (F93 and F146) formed a distinct clade, separate from the newly defined Foc species. No isolate was identified as F. odoratissimum (Foc TR4). Thirty-five strains were classified as F. joanfreemaniae, a member of the F. fujikuroi species complex. In addition, F. solani, F. andiyazi, and F. incarnatum have been reported. Fusarium tardichlamydosporum and F. duoseptatum strains induced symptoms under all tested conditions. Inversely, F. joanfreemaniae caused symptoms on Gros Michel and Cavendish only under stressed, injured roots, indicating a weak or opportunistic role. This highlights a multi-species disease complex with implications for resistance-based management.
Climate change will in many ways affect agricultural production, including the incidence and severity of virus diseases in crop plants. Especially the colder regions of the world face temperature increases and consequently higher risks for virus problems. In a previous study from 2011, increased risks have been identified in Sweden for several insect-transmitted viruses: turnip yellows virus (TuYV) in oilseed rape, yellow dwarf viruses (YDVs) in cereals, wheat dwarf virus (WDV) in wheat, potato virus Y (PVY) in potato, and tomato yellow leaf curl virus (TYLCV) in greenhouse-grown tomato. During the period since then, as predicted, infections of TuYV and YDVs in winter crops have become more frequent because of warmer autumns and the ban on neonicotinoid insecticides. In contrast, the problems with WDV or PVY did not increase over this period, and TYLCV did not become established. With climate change and rising temperatures, it is evident that some virus infections have become more common, while there are many additional factors that restrict the spread of other viruses. For the future, it will be important with increased early monitoring of viruses to identify increases quickly, and with continued efforts for preventing virus spread in crops.
Leaf rot disease is a significant threat to betelvine (Piper betle L.) cultivation in India, causing 20–40
Complex circular leaf spot (CCLS) has emerged as a significant foliar disease of Hevea brasiliensis in major rubber-producing regions, posing a threat to latex yield and the sustainability of plantations. This review consolidates current knowledge on the etiology, epidemiology, diagnosis, and management of CCLS, with an emphasis on its polymicrobial nature involving species from the genera Colletotrichum, Neopestalotiopsis, and Pestalotiopsis. Misidentification of symptoms and pathogens continues to hinder accurate diagnosis and timely intervention. Although chemical fungicides remain central to control efforts, growing environmental concerns and emerging fungicide resistance underscore the urgent need for integrated strategies. Biological control, the development of resistant clones, and improved diagnostic protocols have shown promise but require further validation and broader field-level adoption. This review highlights critical knowledge gaps, including inconsistent surveillance, limited availability of resistant germplasm, and underexplored socioeconomic impacts, particularly among smallholder growers. Recommendations include advancing molecular diagnostics, accelerating resistance breeding, promoting agroforestry practices, and fostering regional extension networks and public–private partnerships. Addressing these challenges will be vital for the long-term resilience of natural rubber production systems in the face of this emerging disease complex.
Lasiodiplodia theobromae is an economically important multi-host plant pathogen infecting nearly 500 hosts, including perennial crops. In Peru, L. theobromae has been identified as the cause of dieback in blueberries, avocados, mangoes, and table grapes. These crops are grown in the northern coastal regions of Peru at temperatures expected to increase due to global warming. We used the aggressive isolate LA-SOL5 of L. theobromae originally isolated from grapevine to study temperature dependence of in vitro vegetative growth, conidiation, conidial germination, and virulence on grapevine cultivar Red Globe. Mycelial growth and formation of pycnidia were optimal at 30 °C, but pre-infection rates of conidiation and conidial germination increased up to 35 °C and correlated well with virulence on grapevine. Our studies show that simple conidiation and conidial germination assays could thus be used to predict development of disease severity and suggest increased severity of L. theobromae–associated dieback in grapes at future climate changes.
