Stem rot spreads in orchards and threatens orange harvest

Stem rot, also known as twig rot, twig gummosis or Bot gummosis, has been a concern for citrus growers due to its increased incidence in recent months. The disease is caused by fungi from the family Botryosphaeriaceae, or “Bot fungi”, including Lasiodiplody e Dothiorella, which become pathogenic when plants face stress, such as high temperatures, intense drought and other diseases.

In the orchards of São Paulo, the thermal and water stress recorded between February and March favored the spread of the disease. The infection causes cracks in the branches, rot in peduncles and fruits, in addition to gum exudation, which can lead to partial or total drying of the tree canopy.

“We had a period of high temperatures and water deficit in February and March of this year, which left the plants severely affected in some situations. In addition to the climate issues, the plants also had other diseases, which left them vulnerable to infections by the Bot fungus. When it rained, the environment became more humid and the fungi infected and colonized the plant tissues, and the symptoms were observed,” highlights Fundecitrus researcher Geraldo Silva Junior.

disease control

Controlling stem rot requires constant monitoring and integrated management with cultural practices, chemical and biological pesticides, and measures to reduce plant stress, such as the use of sunscreens. Since the disease was considered secondary in the citrus belt, there are still few studies on effective control under Brazilian conditions.

Fundecitrus has already begun research to identify the species of fungi involved and evaluate management strategies. In the meantime, citrus growers can seek direct guidance from the entity's technicians to minimize the impacts of the disease on their crops.