Pest and Disease Threats to Olive Trees in Brazil

25/06/2015
Olive Anthracnose Sequence
Antracnose em oliveira em Barra do Ribeiro, RS (Foto: Valmir Duarte)
Fruto de oliveira com sintoma de antracnose, Barra do Ribeiro, RS, jan 2015 (Foto: Valmir Duarte)
Antracnose em folha de oliveira, necrosando o tecido a partir da ponta, Barra do Ribeiro, RS, jan 2015. Pontos escuros são estruturas do fungo (Foto: Valmir Duarte).
Sintoma de antracnose iniciado a partir de ferimento por inseto, oliveira, Barra do Ribeiro, RS, Brasil, jan 2015 (Foto: Valmir Duarte)

Eric Boa, 25 June 2015

Olive oil production is increasing in Brazil, with new plantations starting to bear fruit in Rio Grande do Sul. More trees are being planted to meet increasing local demand as well as target export markets. Brazil is still, however, a net importer of olive oil, with 75000 metric tons from mainly Europe in 2013. Portugal accounted for just over half the imports, followed by Spain (25%) and Italy (6%).
The risk of pest and disease attack on olive trees will increase as Brazil’s own production expands. There is no risk from olive oil but planting material is routinely transferred between countries and olive fruits can harbour pests and diseases. Argentina and Chile also export olive oil to Brazil and possibly olive fruits.
What are the major problems that Brazil needs to be aware of? This is a short list of things to look out for, with background and recent information about pest and disease outbreaks. Italy has been selected for particular attention because of a new disease that has been found in the southeast, in Perugia. But there are other important olive pests and diseases to consider that can cause major losses.
Italy is the second largest olive producer in the world, with 14% of global production or nearly three million tonnes in 2013. During the same period Brazil produced 265 tonnes, ranking 35 out of 39 countries, according to the FAO. In South America, Argentina is the largest producer (172,000 t), then Chile (74,300 t) and Uruguay (6,300 t).
OLIVE FRUIT FLY: this is a regular threat to production in Italy and throughout Europe. Bactrocera oleae was unknown in the Americas until it appeared in California in 1998, probably brought in from France. 
The olive fruit fly has since spread to Mexico, though Mexico is a minor olive producer with no known trade with Brazil.
OLIVE QUICK DECLINE SYNDROME: In 2010 a new disease suddenly appeared in southeastern Italy, south of Bari, the most important olive growing region in the country. The disease was given the name ‘Olive Quick Decline Syndrome’ (OQDS). A syndrome is a collection of symptoms, and as this name suggests there was uncertainty about the cause when OQDS was first seen.
In 2013 the bacterium Xylella fastidiosa was found in association with OQDS. The role of the bacterium is still unclear, but there is growing evidence that Xylella plays an important part in the decline of olive trees. It is a well-known pathogen which affects many hosts, including grapevine, almond, coffee and citrus. There are at least four subspecies, with different host ranges and distributions. Typical symptoms include scorching of leaves – they look as if they’ve been damaged by fire – combined with reduction in growth and sometimes death of the plant.
Xylella fastidiosa already occurs in Brazil and South America but there are no records on olive trees. It is important to remain vigilant, however, and to inform the plant protection authorities of suspected or suspicious symptoms.
Control programmes have proved controversial and farmers have expressed anger as well as frustration about the need to cut down trees, a preventative measure aimed at restricting the spread of disease to new areas.
Puglia region has produced a guide on managing OQDS (see link below). The guide is in Italian, but that should not be a problem in Rio Grande do Sul! The guide contains many useful photographs.
OLIVE ANTHRACNOSE: Anthracnose is a common symptom on many plants, characterized by sunken, black regions. Recent reports from Uruguay and field visits to olive plantations near to Porto Alegre suggest that this damaging disease is already affecting trees in Brazil. The photograph shows a range of symptoms recently found in Rio Grande do Sul. Note the dark patches on the fruits and the underlying black areas. Leaves also appear to be affected by anthracnosis.
The fungus Colletotrichum is the main cause of anthracnosis. Different species attack different hosts though Colletotrichum gloeosporioides has a wide host range. Coffee berry disease (only found in Africa) is a feared disease in Kenya, caused by C. kahawae. The spores of Colletotrichum have been found on olive fruits near to Porto Alegre but we don’t know yet which species is involved. This is not a new disease record for Brazil.
In Puglia, olive anthracnose was estimated to cause US$71 million of damages in 2011. Although the disease causes widespread losses, the research response has been weak and poorly coordinated according to a leading Italian researcher.
Effective control measures include pruning of diseased branches and twigs, reducing the carry-over of the disease from one season to the next. Copper-based fungicides have not worked, partly because the timing of sprays has been too late to prevent disease build up. There is a suggestion that foliar application of nutrients between fruit set and harvest may be helpful, but more research is needed before this can be recommended with confidence.
DO YOU HAVE CONCERNS ABOUT OLIVE TREE PROBLEMS? Agronomica is always keen to know about them and has the testing facilities to investigate possible causes. Contact us for more information.
Links
 Management of Olive fruit fly: 
http://www.ipm.ucdavis.edu/PMG/PESTNOTES/pn74112.html
 Olive Quick Decline Syndrome:  
http://cartografia.sit.puglia.it/doc/LINEEGUIDA_XYLELLAE_CoDiRO.pdf
 Olive anthracnose in Italy:  
http://www.oliveoiltimes.com/olive-oil-making-and-milling/anthracnose/25145
 Xylella fastidiosa in Italy, controversy about control campaign:  
http://www.nature.com/news/italian-scientists-vilified-in-wake-of-olive-tree-deaths-1.17651
 Brazil olive oil imports:
http://www.oliveoiltimes.com/olive-oil-business/south-america/brazilian-olive-oil-imports-boom/38050

 


Sobre Eric Boa

A carreira profissional do escocês Ph.D. em Fitopatologia Eric Boa se estende por 23 anos e tem raízes na pesquisa agrícola. Tem experiência em treinamento em diagnóstico fitossanitário para engenheiros agrônomos, inspetores fitossanitários, equipes de assistência técnica, agricultores, comerciantes agrícolas e muitos outros na América Latina, África, Ásia e Europa, por mais de 20 anos. Trabalhou durante 15 anos como pesquisador no CABI, organização filantrópica internacional focada em melhorar a vida da população levando conhecimento científico para resolver problemas da agricultura e meio ambiente. É expert em saúde de plantas, sistemas agroflorestais (bambu) e florestais não madeireiros (selvagem útil fungos); e prestação de serviços nas áreas comuns ("GOING PUBLIC").