Greening survey shows advancement of the disease in the citrus belt

The annual survey of the incidence of greening (huanglongbing/HLB) carried out by Fundecitrus indicates that the average incidence of the disease rose from 22,37%, in 2021, to 24,42% in 2022 throughout the citrus belt of São Paulo and Triângulo/Southwest Miner. A growth of 9,16%.

The situation requires more effort from citrus growers for more effective control. In the regions of Brotas, Limeira and Porto Ferreira, where the incidence was already high in previous years, greening increased to even more worrying levels, with 49,41%, 70,72% and 74,05% respectively. “We are seeing the disease grow at a rate that is worrying. However, at the same time, the results obtained on properties in regions that have seen a decline or stabilization of the disease reinforce our confidence that measures to combat greening are effective. This has always been the path and always will be, until we can reach plants resistant to the disease. However, we need more efforts”, reinforces the general manager of Fundecitrus, Juliano Ayres.  

Regions

In the regions of Avaré and Duartina, incidences are above the belt average, with 31,80% and 25,37%, respectively. However, there was a reduction in the progress of the disease in these two regions compared to previous years. In the regions of Altinópolis and Bebedouro, the observed incidences remain below the average for the belt, with 15,96% and 7,43%, respectively. The negative point was the significant increase in incidence in the regions of São José do Rio Preto (from 5,32% to 14,50%) and Itapetininga (from 4,25% to 7,15%), regions that had low incidences in previous years. Positively, in the Matão region, the incidence has been decreasing in the last six years (8,90%) and in the Triângulo Mineiro and Votuporanga regions, the incidences remain very low (less than 0,1%),

Growth

According to the survey, several structural and cyclical aspects contributed to the increase in the spread of greening. In most regions, in addition to the favorable climate, there is a high density of orchards and a large number of medium and small properties, making it difficult to coordinate joint actions for regional management of the disease. However, the most important thing is that in most orchards in production, diseased trees are not being eliminated and psyllid control has been inadequate. Inefficient spraying has also contributed to the growth of the index. “This work is not being done frequently enough, especially during budding times. Failures in spray coverage have also been observed, mainly at the top of the canopy of adult trees and in dense orchards”, explains Fundecitrus researcher Renato Bassanezi.

Another extremely important factor that has hampered the effectiveness of psyllid control is the repetitive use of insecticides from the pyrethroid group without adequate rotation with insecticides with other modes of action, a fact that recently led to the detection of psyllid resistance to this group. chemical in some places.

Cancer and CVC

The survey prepared by Fundecitrus also points to an increase in the incidence of cancer in orchards. According to the new survey, the disease is present in 18,77% of trees, an increase of 74,44%. The current index reflects the incidence of affected orchards in 2020, which was 17,26%. The disease accounts for 0,21% of fruit drops recorded across the entire belt. The low rate is related to studies carried out by Fundecitrus that adjust the use of copper in managing the disease, without affecting the effectiveness of the treatment and generating savings of 56% in the amount of product per hectare.  

The incidence of CVC remains low throughout the citrus park, with an incidence of 0,80% in 2022. Around 20 years ago, the disease was present in 46% of the trees. The significant reduction is mainly due to the evolution of research and management practices disseminated by Fundecitrus.

The complete survey is available on the Fundecitrus website available here.