In Greece, Olive Trees Suffer From Fruit Fly Infection Ahead of Harvest

The unstable weather of the past summer and the lack of resources to fight the fly are to blame for an ominous outlook.

Groves at Laconiko in Laconia, Greece (File Photo)
Sep. 21, 2018
By Costas Vasilopoulos
Groves at Laconiko in Laconia, Greece (File Photo)

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Last year’s olive har­vest in Greece beat expec­ta­tions, with almost 350,000 tons of oil com­ing out of the mills. The rich pro­duc­tion came after the much-debated drought had min­i­mal effects and there was prac­ti­cally no fruit fly inva­sion that would degrade both the qual­ity and the quan­tity of the olive oil.

This is an empty sea­son for us. We expect to get only 40 per­cent of last year’s pro­duc­tion.- Giorgos Korinnis

But this sea­son is a dif­fer­ent story with the har­vest expected to be slim­mer mainly due to the pro­duc­tion cycle of the olive trees, and the olive fruit fly has again made its pres­ence felt in many areas of the coun­try.

The lack of the usual heat waves that hit Greece every sum­mer and that would ren­der the fly inac­tive, com­bined with the unnat­u­rally high lev­els of rain, enabled the pest to repro­duce and threaten the forth­com­ing pro­duc­tion. A sin­gle female fruit fly can deliver about 200 eggs and after a month the new flies emerge with half of them being females able to make 200 eggs more. They expo­nen­tially increase their pres­ence and it becomes hard to con­tain them if they start hatch­ing.

Giorgos Korinnis, an agri­cul­tur­ist work­ing in Lakonia, which tra­di­tion­ally makes top-qual­ity olive oil, told Olive Oil Times that the infes­ta­tion from the fruit fly is more than obvi­ous this sea­son.

This is an empty sea­son for us,” Korinnis said. We expect to get only 40 per­cent of last year’s pro­duc­tion which was around 25,000 tons of olive oil for the whole region, and a sig­nif­i­cant part of it will come from olives infected with the fruit fly. So, due to the dam­age the fly causes, I wouldn’t be sur­prised to see olive oils with an acid­ity level of 0.5 or 0.6 when we nor­mally get 0.2 or 0.3, mean­ing that a big part of the oil crop will be of lower qual­ity than what we usu­ally get here.”

Korinnis also explained that the prob­lem started with the mild weather con­di­tions that pre­vailed dur­ing the sum­mer. We had no tem­per­a­tures exceed­ing 35°C (95°F), so the fly could eas­ily repro­duce itself. And many grow­ers did not bother to use any pes­ti­cides to get rid of the fly since they weren’t expect­ing any seri­ous yield, so the fly got the chance to incu­bate in their trees sub­se­quently con­t­a­m­i­nat­ing neigh­bor­ing olive groves with bet­ter prospects and affect­ing this way the olive oil crop of the whole area.”

Konstantinos Papadopoulos of the Papadopoulos Olive Oil Mill near ancient Olympia, told OOT there is an out­break of the olive fruit fly in the area. Some pro­duc­ers took mea­sures to reduce the dam­age, but the major­ity unable to do so mostly due to lim­ited bud­get. Some of the pro­duc­ers we work with will get qual­ity olive oil this sea­son, but gen­er­ally we expect a very low yield of infe­rior qual­ity,” he noted.

In Crete, Peza Union near Heraklion is a big asso­ci­a­tion of olive oil pro­duc­ers. They told us that until now the fruit fly was only active in small pock­ets all over the dis­trict, but they expect it to spread since there is not going to be any more pes­ti­cide appli­ca­tion in the fields due to lack of resources. Nevertheless, and con­trary to the sit­u­a­tion in most parts of the coun­try, they expect an increased pro­duc­tion by 20 to 30 per­cent com­pared to last year.

Reports are also com­ing in from other olive oil-mak­ing ter­ri­to­ries of the coun­try, indi­cat­ing that the sit­u­a­tion is grim.

The island of Lesvos, with its dis­tinc­tive yel­low­ish olive oil, is on the verge of los­ing much of its pro­duc­tion due to the extended fruit fly infec­tion, accord­ing to pro­duc­ers. Weather and the slow response by farm­ers made it easy for the fly to nest and repro­duce. The local admin­is­tra­tion added that organic olive groves, which con­sti­tute 25 per­cent of the island’s olive tree cul­ti­va­tions, also con­tributed to the fly’s spread­ing since their own­ers avoided using any means to con­tain it in order to pro­tect their organic iden­tity.

In the Aetolia-Acarnania region in Central Greece, there are many olive groves infected by the fly and the local pro­duc­ers expect a lesser pro­duc­tion than the pre­vi­ous sea­son. To add insult to injury, many trees that were untouched by the fly were hit by hail that punched the olive fruits to the ground and left pro­duc­ers in despair.

In the neigh­bor­ing area of Lokrida, almost all of the olive oil pro­duc­tion of the area is expected to be affected by the fruit fly. The pro­duc­ers accused the author­i­ties of being slug­gish in apply­ing mea­sures to destroy the fly and asked for com­pen­sa­tion.

There is also a notice com­ing from the author­i­ties of Northern Greece for a very high activ­ity of the fruit fly near the city of Alexandroupoli and other areas, urg­ing the pro­duc­ers there to use pes­ti­cides to min­i­mize the loss.

Back in the day, pro­duc­ers in Greece used to say that a hot and dry sum­mer is all that is needed for olive oil of excel­lent qual­ity. But now, with the weather con­stantly chang­ing, the old wis­dom is not enough and grow­ers and pro­duc­ers have a lot of para­me­ters to con­sider for a suc­cess­ful olive oil crop.


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  1. Lettingo says:

    Well, I think its time to dis­cuss for the root causes of the high pres­ence of the olive flies and for real mea­sures that will be soon manda­tory to

    take. ANd the root causes is not the lack of spray­ing with insec­ti­cides, or the rain-drought cycles (Which we have no con­trol over). The causes are more related with the mono­cul­ture cul­ture, the killing-exter­mi­na­tion of the nat­ural preda­tors of the fly, that goes together with the exten­sive spray­ing and the hes­i­tance of every­one involved in the olive oil pro­duc­tion chain to incor­po­rate a dif­fer­ent approach and dif­fer­ent mea­sures. The solu­tion will be to move towards what not only Organic agri­cul­ture and even Agro 2.0 pre­scribe, but to look even ahead to the prin­ci­ples that are included in the Regenerative agri­cul­ture meth­ods. It is almost delu­sional to believe that in thou­sands of hectares grown only with olive trees, the olive fly, as species that actu­ally uses only the olive fruit for its life-cycle, can be erad­i­cated. We (the pro­duc­ers) have cre­ated the con­di­tions which we are now com­plain­ing about. Depleting the soil, cre­at­ing weak trees and very sen­si­tive agro-eco-sys­tems are the causes behind the threats to pro­duc­tiv­ity. The use of fly-traps with prod­ucts such as entomela, have been suc­ces­ful, but they can not solve the issue by them­selves. A more holis­tic approach needs to be taken, as we are deal­ing with SYSTEMS and not just OLIVE TREES. If we con­tinue in the same path, in a very short time from now, olive pro­duc­tion can be severely jeop­ar­dized and olive oil will need to face a decrease in qual­ity and an increase in the pro­duc­tion costs will be evi­dent. Greece can play a lead­ing role in the new move­ment towards a truly sus­tain­able and regen­er­a­tive agri­cul­ture.

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