MercoPress. South Atlantic News Agency

Paraguay reports outbreaks of ‘greening’ in its citrus plantations

The disease is distinguished by the common symptoms of yellowing of the veins and adjacent tissues

Paraguay’s plants and seeds sanitary office, SENAVE, has reported 63 outbreaks of ‘greening’ or HLB in citrus groves and further admits that the geographical dissemination state of the bacterial canker disease is in “an advanced stage” despite all institutional efforts.

“Greening” or canker or ‘huanglongbing’ is a rapidly spreading disease among citrus which has devastating effects for fruit growers. The causative agents are motile bacteria, transmitted by the Asian citrus psyllid (Sternorrhyncha: Psyllidae.

The disease is distinguished by the common symptoms of yellowing of the veins and adjacent tissues; followed by yellowing or mottling of the entire leaf; followed by premature defoliation, dieback of twigs, decay of feeder rootlets and lateral roots, and decline in vigor; and followed by, ultimately, the death of the entire plant.

Affected trees have stunted growth, bear multiple off-season flowers (most of which fall off), and produce small, irregularly-shaped fruit with a thick, pale peel that remains green at the bottom. Fruit from these trees tastes bitter.

There is no cure for Huanglongbing and efforts to control the disease have been slow because infected citrus plants are difficult to maintain, regenerate, and study.

“We need to implement a national program with a strong presence of national authorities to avoid the disappearance of the country’s citrus production” warned Agronomist Fernando Rios head of the SENAVE.

HLB has devastated citrus production in several countries such as in Florida, US; Cuba and in Brazil in the states of Sao Paulo and Parana, from where Paraguayan authorities believe the contagion was introduced into the land-locked country.

According to the 2008 plants census Paraguay had 1.3 million plants of sweet orange; another 770.000 ready for production; 370.000 plants of tangerine and 23.5 million of bitter orange.

Paraguay’s plants and seeds sanitary office, SENAVE, has reported 63 outbreaks of ‘greening’ or HLB in citrus groves and further admits that the geographical dissemination state of the bacterial canker disease is in “an advanced stage” despite all institutional efforts.