Entities from Paraná join forces to tackle greening

Paraná joined forces to combat greening, one of the main pests that affect citrus trees in the world. The objective is to control the disease and its main vector, the psyllid Diaphorina citri Kuwayama. The eradication of diseased plants followed by planting healthy seedlings from registered nurseries and efficient insect control with biological and chemical products are some of the good practices.

The actions are carried out by the Government, through the State Secretariat for Agriculture and Supply, the Paraná Agricultural Defense Agency (Adapar) and the Paraná Rural Development Institute (IDR-Paraná), together with agricultural research companies, cooperatives, city ​​halls and the industrial sector.

Activities were intensified from August onwards with Operation BIG Citros, which involves raising awareness, monitoring and reinforcing measures to prevent and control greening, also known as HLB (Huanglongbing) or yellowing. The work extends across the municipalities in the northwest of the state, where the largest concentration of citrus production in Paraná is located.

No cure

There is still no known cure for greening disease. The eradication of contaminated plants and good psyllid control practices are the recommended alternatives. The city of Paranavaí began the process of cutting down plants contaminated by the disease. The action began in Vila Rural São João, accompanied by agronomists who attested to the situation before the cuts.

Rogério Goulart Pedro's property was one of those that went through the process. There, 25 trees of ponkans, oranges, lemons and tangerines were cut, with ages varying between four months and five years. “I had never heard of this disease and I ended up becoming aware of the problem now”, said Pedro.

According to him, the fruits were used for consumption by the family itself. With the clarifications given by the technicians, he believes that the attitude is correct. “The region will certainly benefit”, he ponders. And he guarantees that he will resume planting, “as long as he has authorization from the responsible body”.

The work to eradicate diseased plants is carried out both on rural and urban properties with fruit for family consumption and in commercial orchards. At the same time, there is an inspection effort to ban the sale of illegal seedlings.

Disease

HLB or citrus greening is an important pest due to its severity, rapid spread and control difficulties. In Brazil, the bacterium Candidatus Liberibacter asiaticus (CLas) is the main causal agent of HLB. The disease affects plants of practically all citrus species, in addition to myrtle (Murraya paniculata), Fortunella spp. and Poncirus spp., and is transmitted by the Asian citrus psyllid Diaphorina citri Kuwayama.

Greening seriously affects citrus plants, mainly due to premature fruit drop, which results in reduced production and can lead to early death. Furthermore, the fruits become smaller, deformed, and may have aborted seeds, reduced sugars and high acidity, which depreciates their flavor, reducing quality and commercial value, both for fresh consumption and for industrial processing.

Considering the seriousness of this phytosanitary problem, Adapar, the Institute for Rural Development of Paraná (IDR-Paraná) and the Secretariat of Agriculture and Supply issued a Technical Note at the end of July.

Good habits

One of the practices to avoid the disease is the planting of healthy, quality seedlings from registered nurseries. In Paraná, the sale of plants through street sales is prohibited. Preventive management also includes the use of windbreaks and planting density. Psyllid control can also be done with Tamarixia radiata, a wasp created in laboratories, including that of IDR-Paraná, whose eggs serve as food for nymphs, eliminating them.  

Good fertilization, quality irrigation and vegetation cover are also good allies for the rapid development of the plant, reducing exposure to the insect, as transmission is more common in sprouts than in adult leaves. Monitoring and control of the insect vector must be carried out in accordance with technical recommendations, installing yellow traps and counting them every seven days.

Spraying at intervals that respect agronomic guidelines is important, with the use of chemical and biological insecticides with proven efficiency. It is also recommended to rotate insecticides, which must be applied using all techniques that eliminate the possibility of drift.

Production value

The area occupied by citrus farming in Paraná is approximately 29.200 ha, with 20.700 ha of oranges, 7.000 ha of tangerines and 1.500 ha of Tahiti acid lime. The Gross Value of Citrus Production totaled R$826,8 million with the production of 842,4 thousand tons of fruit (SEAB/Deral, 2022).

The municipalities of Paranavaí, Alto Paraná, Guairaçá, Nova Esperança and Cruzeiro do Oeste stand out, with orange production; Altônia, with the production of acid limes, and the municipalities of Cerro Azul and Doutor Ulisses, with the production of ponkan tangerine.