Paraná declares phytosanitary emergency to combat "greening"

The determination occurred through Decree 4.502/23, published this Tuesday; The objective is to have greater mobility and the possibility of acting more quickly and effectively

26.12.2023 | 10:16 (UTC -3)
Secretariat of Agriculture of Paraná, Cultivar Magazine edition

Paraná is in a phytosanitary emergency to combat "greening", a pest that affects citrus. The determination occurred through Decree 4.502/23, published this Tuesday (26/12). The objective is to have greater mobility and the possibility of acting more quickly and effectively to control the disease and its vector, the psyllid. diaphorina citri.

The decree provides for liability:

Art. 5º Owners of rural or urban establishments are obliged, at their own expense, to eradicate HLB host plants, defined in this Decree, under penalty of liability based on Law No. 11.200, of November 13, 1995, its Regulations and other applicable standards .

“Farmers carry out activities in the open air and are subject to various natural interferences, which can be climate or diseases and pests”, said the secretary of agriculture and supply, Norberto Ortigara.

“The phytosanitary emergency decree is a drastic instrument, but it gives us the possibility of taking the necessary measures more effectively in an attempt to control the problem, as citrus farming is a very important activity for the State.”

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 pest has appeared more frequently in the Northwest region, where most commercial citrus plantations are located, but it also extends across the North of the State.

Since the detection of an abnormal increase in the disease, the State has joined forces to prevent and control "greening", also known as HLB (Huanglongbing) or yellowing.

There is still no known cure for greening disease. The eradication of contaminated plants and good psyllid control practices are the recommended alternatives. In several municipalities in the affected regions, city halls have decisively entered the process and are cutting down the plants.

The work 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. Sales, normally carried out in cars or on sidewalks, are prohibited in Paraná.

About citrus greening

Huanglongbing disease (HLB; formerly called citrus greening) is an important pest due to its severity, rapid spread and difficulties in control. The bacteria Candidatus Liberibacter is the 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.

Greening seriously affects citrus plants, causing premature fruit fall, 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.

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. Psyllid control can also be done with the tamarixia radiata, a parasitoid wasp created in laboratories, including that of IDR-Paraná.

In the field, T. radiata look for the nests of diaphorina citri to reproduce. They lay their eggs under the nymphs (young form), which will serve as food for the larvae. Each wasp can eliminate up to 500 psyllids. This promotes a reduction in the number of vectors and the incidence of the disease. The use of this biological component, which is a complementary alternative to combat "greening", also implies less insecticide application.

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 essential to rotate the chemical groups of insecticides, which must be applied using all techniques that eliminate the possibility of drift.

The full decree can be read at the link below.

LS Tractor February