Cowpea mild mottle virus (CPMMV, genus Carlavirus, family Betaflexividae) is an economically important virus infecting soybeans in Brazil, where it was initially identified in 1983. CPMMV is transmitted by the whitefly, Bemisia tabaci, and occasionally by seeds. Over the last three decades, the most invasive B. tabaci Middle East–Asia Minor 1 (MEAM1), and lately the Mediterranean (MED) cryptic species, have replaced the indigenous species in Brazil, with MEAM1 being predominant. In this study, we investigated the transmission properties of CPMMV by MEAM1 and MED, and their distribution in major soybean-growing areas in São Paulo State. Our results from transmission assays with a single insect revealed that MED is a more efficient vector compared to MEAM1, transmitting the virus within a two-minute inoculation access period. B. tabaci MEAM1 is still the predominant whitefly species in São Paulo State, but MED was also identified in different places, mainly in mixed infestations with MEAM1. Some areas transitioned to a predominance of MED over the three years, while others, where MED had previously been detected, showed a reduction in the insects during the same period. Understanding the transmission dynamics of CPMMV and the distribution of its vectors is crucial for implementing effective management strategies to control the virus spread and protect soybean crops. Further research into the mechanisms driving the shifts in whitefly species dominance and CPMMV distribution will be essential for sustaining soybean production in Brazil.

The tomato (Solanum lycopersicum) is an important crop to the economy of Brazil, and the whitefly Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae) is one of the limiting factors responsible for reducing its yields. These insects are part of a cryptic species group present across almost the entire globe. The most relevant cryptic species in the world are B. tabaci MEAM1 and MED due to their capability to adapt and cause damage to vegetables, grain, and ornamental crops. The arrival of MED in Brazil through the state of São Paulo represents risks to farmers in the region due to the difficulty in managing these insects. This study assessed the occurrence of both species in tomato crops in the southeastern region of Brazil in 2020 and 2021. An amount of 79 samples containing 767 insects were collected throughout the study period, and in the cities of Sumaré (SP) and Monte Mor (SP), several samples were collected from the same location throughout the year. The insects were stored and sent for molecular analysis. The results showed an increase in MED compared to MEAM1. The presence of MED in the Minas Gerais samples was not recorded. However, a higher percentage of MED was observed in the state of São Paulo, which was detected in the municipalities of Sumaré and Monte Mor. These results possibly indicate that MED could be starting to stabilize in open tomato fields in Brazil.

Orthotospoviruses affect vegetable, leguminous and ornamental plants globally and are transmitted by thrips (Order Thysanoptera). In Brazil, groundnut ringspot orthotospovirus (GRSV) has recently been reported infecting soybean plants in Bahia state and the Federal District. To ascertain the impact of orthotospoviruses on soybean cultivation, soybean leaves and thrips were collected from 2020 to 2022 in the most important soybean‐producing areas of São Paulo State. Virus detection was conducted through reverse transcription‐PCR, followed by partial sequencing of the nucleocapsid gene. Additionally, morphological identification of the thrips was performed. GRSV was found to be widespread across São Paulo State's soybean fields, with Frankliniella schultzei identified as the predominant thrips species over Caliothrips phaseoli and Frankliniella occidentalis . Partial genomes of GRSV isolates revealed a high degree of identity in the nucleocapsid gene sequences. Biological assays involving four distinct GRSV isolates from soybeans demonstrated variable sap transmission efficacy to soybean, tomato, sweet pepper and tobacco plants, some isolates not being transmitted. Seeds obtained from infected soybean plants were grown, and two seedlings out of 1000 tested were positive for GRSV. To the best of our knowledge, this is the first evidence of GRSV seed transmission and because GRSV is the predominant orthotospovirus in Brazil, these findings have great epidemiological implications on orthotospovirus epidemiology.

Potato is a vital food source worldwide, but its production is frequently threatened by viral diseases. Tomato chlorosis virus (ToCV) primarily affects solanaceous crops, especially tomatoes. Although ToCV has been reported in potatoes, its relevance in this crop remains understudied in Brazil. This study evaluated the incidence of ToCV in major potato‐producing regions of São Paulo state and identified the predominant whitefly species. Transmission efficiency of ToCV by Bemisia tabaci MEAM1 and MED, vertical transmission via tubers, and the latent and incubation periods in potato plants were also investigated. Field surveys (2022–2024) showed a low ToCV incidence in potato crops. MEAM1 was the predominant whitefly species, whereas MED was detected at a single location. MED transmitted ToCV to potato plants of cv. Agata with higher efficiency (36.6%) than MEAM1 (10%), but no significant difference was observed for plants of cv. Asterix. Vertical transmission rates via tubers were high, reaching 76.7% for cv. Agata and 88.1% for cv. Asterix. The mean latent period was 8 days, with symptom expression approximately 35 days post‐inoculation. These findings suggest that ToCV is currently not widely distributed in potato crops in São Paulo state. However, the high vertical transmission rates and the demonstrated transmissibility by both MEAM1 and MED highlight the potential risks for future spread. Continued monitoring of potato fields and whitefly populations is crucial to mitigate the potential risk posed by ToCV in the region.