Olive fruit deformation has become important problem in Turkey. Boron is considered to cause this deformation. Deformation regards not only flesh but also kernels of fruits in case of boron deficiency. Another type of deformation was also observed as the bumpy on the flesh without showing any deformations on the kernel. In case of Bumpy deformation, Boron deficiency was not determined by soil, fruit or leaf analysis. Some studies showed that Eriophyoids and some viruses to cause olive fruit deformation. Our aim was to carry out: soil, fruit, leaf and water analyses; virus analyses by molecular identifications; evaluation of Eriophyoids on the olive trees in the same conditions. Such investigations were performed to understand the causes of the different deformations. Presently, it is generally recognized that physiological conditions have great impact on bumpy deformation. A multidisciplinary study related to this problem was realized for the first time at the international level.
National Olive and Oliveoil Councel - TurkeyInitiative partner
100. YIL UNIVERSITY, FACULTY OF AGRICULTURE, DEPARTMENT OF PLANT PROTECTION - TurkeyInitiative partner
Ege University, Faculty of Agriculture, Department of Horticultural Crops - TurkeyInitiative partner
olive fruits with orange peels (bumpy fruits)
Deformations cause the loss of table olive quality and olive oil quantity. According to previous reports, deformations of olives are caused by boron deficiency, viruses or Eriophyidae. Our research reported that there are two types of deformations on olive fruits. Boron deficiency causes monkey face in fruit flesh and bigger size of kernels. Excessive irrigation and deep tilling can cause deformations called “bumpy” (physiological deformations) on the olive fruits if trees are grown in clay soil.
In case of monkey face deformation, we identified Boron deficiency in soil and leaves analyses.
In case of Bumpy deformation, we observed that deformations of fruits occurred in olives when they were irrigated more than 4-5 times/year if the weather was dry.
In the begging, deformation of olives was observed only with Ayvalik local variety. Then, also other irrigated varieties for table and oil productions, such as Domat, Memecik, Gemlik, were also affected.
Deformations on the olives decrease fruit quality for table consumption and oil quantity for olive oil productions thus causing economic losses for growers. Researchers and growers were convinced that deformations of olives were caused by Boron deficiency, Eryophides and viruses, as a consequence, the use of pesticides Boron treatments were widely applied. These applications do not solve problems and can cause damages to human healthy, environment and eco fauna of olive orchards, because of the high levels of pesticide contents.
Our results showed that there are two types of deformations. One deformation is caused by Boron deficiency, Eryophides and viruses. A second type of deformation is caused by physiological deficiencies caused by excessive irrigations and deep tilling on the olives when trees are grown in a clay soil. Deformation caused by physiological problems, of course, does not need the use of any pesticide and boron application.
Survey works were carried out for four years; 38 olive orchards were chosen. Two sampling were made from each field. Samples were formed from leaves, fruits and soils. Following the survey we conducted, we detected Bumpy deformation that caused by physiological problems. We have determined that this economically important deformation problem can be prevented/controlled with some simple practical applications. We found that deformation problem can be controlled by cultural management means such as controlled amount/frequency of irrigation and shallow tillage.
The real beneficiaries of this work are farmers, consumers and the environment. Deformations of olives has become an important concern for olive growers. It causes the decreased quality of table olives and decrease in quantity of oil extracted. Physiological deformations called as Bumpy type, are easily solved by reduced irrigation and shallow tilling. Treatments are not necessary for Bumpy type physiological deformations because of that water, irrigation and machinery costs can be reduced. Furthermore, products without any residues are beneficial both for consumer’s health and environment.
This work was carried out as a joint work by the Turkish Ministry of Food, Agriculture and Livestock Olive and Olive Oil Research Institution, Plant Protection Research Institute, Ege University and Van 100 Yil University.
The research program was realized by Dr. Mustafa Tan (manager), Dr. Handan Ataol Olmez(coordinator), Dr. Ilhan Ozkarakas from Olive and Olive Oil Research Institution(coordinator), Dr. Serpil Erilmez from Plant Protection Institute of Izmir, Prof Dr.Uygun Aksoy from Ege University, Prof. Dr. Serap Acikgoz from Aydin University, Doc. Dr. Evsel Denizhan from Van 100. Yil University.
Deformations does not occur every year. Time to time there is even no deformations. Because of that we were not able to conduct this research every year to have solid results. We had to wait for the years with deformation problem to have results and survey took quite long because of that. We had to do a lot of research at the beginning due to not knowing what was causing this problem. Furthermore, in order to determine Bumpy deformation we had to do lots of analyses such as Eryophides, Virus, Born Deficiency since 2007.
We have determined that deformation was due to physiological reasons in irrigated lands. Deformations were occurring especially in the dry years when irrigation frequency increased and we found that it can be prevented by shallow tillage and less frequent irrigation (max. 4 times). Preventative actions decreases the costs due to reduced machinery and water use. We found that physiological reasons related deformation are different than born deficiency related deformation and farmers can reduce their inputs with less machinery and less pesticides use. Complete comprehension of problems that are related to simple cultural management will contribute to farmers by reduced costs and will contribute the product by increased quality. At the end those two will contribute together to farmers income in positive way and practices will provide consumers high quality products without residues.
It was believed that deformation problems was only occurring in local varieties of Ayvalik. Our results are in contrast due to detected deformations also in other varieties such as Trilye and Domat which were also irrigated. This study and its results also inspires us to conduct similar studies on other varieties in order to detect causes of deformations in that varieties.
We have published a book to spread the results of this work and we are currently preparing scientific papers.
We organized workshop Group to discuss our results.