The annual survey of the incidence of greening (huanglongbing / HLB) made by Fundecitrus indicates that 20.87% of the orange citrus belt of São Paulo and Triangle / South of Minas Gerais have symptoms of the disease, considered the most destructive of the world’s citrus industry, the which corresponds to about 41 million trees. The index is 9.7% larger than 2019, estimated at 19.02%.
The general manager of Fundecitrus, Juliano Ayres, shows concern about the disease growing trend, but highlights the presence of regions where the incidence following low and where the disease decreased or stabilized.
“On the one hand, the data light up a warning sign to the need of reducing the incidence of citrus greening in the park. Thus, the recommendation is that growers intensify the internal management, strictly in the insect vector control and elimination of diseased plants, and also the external management which consists in replacing citrus plants without control and myrtle around the farms business, in places such as abandoned orchards, yards and sidewalks, in other species of ornamental and fruit, which are not attractive to the psyllid “he emphasizes. “On the other hand, there is good news: in addition to the neighboring regions of the belt citrus follow with low incidence, the external management, when combined with strict internal management is effective and influenced the reduction and stabilization of disease considered critical areas such as Matao, region where the disease emerged in the country, and Duartina “he says.
Since 2018 Fundecitrus has invested in supporting growers to improve the integrated management of the properties and adoption of external management actions, enabling the creation of joint working groups, with the transfer of knowledge and new technologies for control more efficient and sustainable .
The greening was identified in Brazil in 2004 and since then, advances in research have managed to maintain the competitiveness of the citrus belt SP and MG, the largest orange-producing region in the world for juice. Despite the increase in the average incidence of greening the third consecutive year, the index remains well below the over 90% estimated in Florida (USA). The American state which has been a leading producer of oranges, harvested this year, its second lowest harvest since the arrival of the disease in 2005.
INCIDandINSTANCE by royalThe
Regions with the highest incidences remain Brotas (60.46%), Limerick (53.18%), Porto Ferreira (33.67%) and Duartina (30.81%). In an intermediate range are regions of Avare (16.77%), Altinopolis (15.73%) and Matão (14.47%). Trough (8.92%), San Jose Rio Black (3.5%), Votuporanga (0.08%), Minas Triangle (0.08%) and Itapetininga (1.63%) are the regions with lower incidence .
In Matao, Duartina, Sao Jose do Rio Preto, Votuporanga, Mineiro Triangle and Itapetininga disease decreased or stabilized, that is, the incidence remained within the past five years. In Brotas, Limeira, Ferreira, Avare, Altinópolis and Trough was no increased incidence.
INCIDandINSTANCE lower in extreme
The extremes of citrus belt (Triangle Mineiro, Votuporanga and Itapetininga) have, historically, the lowest incidences of greening, and the weather has a decisive influence on this scenario: both the high temperatures and the drought observed in the north and northwest sectors as the most temperatures Southwest casualties are less favorable to the development of the psyllid and the bacteria that causes the disease. In the more central regions, the climate is more favorable to both practically all year round.
strict internal management and external actions influence diminuiçãthe greening
Despite having favorable weather conditions for the development of greening, the incidence of the disease declined in the third year Matão (-16.3% compared to 2019) and stabilized in Duartina (-5%), although it is still considered high . These regions had the highest participation rates in the external management actions made in partnership with Fundecitrus, 77.4% and 51.9% of the commercial area of citrus, respectively. Sao Jose do Rio Preto, which maintains low incidence, is 43% of the commercial area of citrus in the region participating in external actions.
Orchards older and smaller farms have higher INCIDandTRENDS
Considering the age of orchards, most greening effect was observed in those over 10 years (28.59%), followed by orchards 6 to 10 years (20.35%), 3 to 5 years (11.36 %) and from 0 to 2 years (1.69%), indicating that there is a good accuracy in the management of disease in young orchards, to control and eliminate patient psyllid plants, and less accuracy in the elimination of diseased plants adults orchards.
“The maintenance of adult plants patients in orchards hinders the reduction of the disease in the coming years and possibly result in an increase in the severity of symptoms, with worsening of premature drop rate of fruit, reducing the production and quality of the fruit and higher risks in the implementation of new orchards, “warns the researcher Fundecitrus Renato Bassanezi.
The smaller the property, the higher the incidence of plants with symptoms of greening. All properties up to 10 thousand plants (up to 21 hectares), the incidence is 44.07%, and the farms between 10.1 to 100 thousand plants (21.1 to 210 h), the incidence is 30.83 %.
This is the so-called “edge effect”: the smaller properties have most of their localized trees on the edge of plots, ie, in the first 100 meters from the exchange, where most coming psyllids out settles and consequently, having greater incidence (23.42%) than the inner plots of orchards (12.81%). However, the larger the impact property increased with respect to 2019 and in 18.93% of the farms 100 100 200 thousand plants (210.1 to 420 hectares) (17.1%); and 12.89% in the properties of more than 200 thousand plants (over 420 h) (+ 26%).
This text was translated by machine from Brazilian Portuguese.