Current olive farming situation
In our days
Nowadays, the need for support and development of the primary sector receives increasing attention both at national and global level. The reason is obvious and relates to the importance that modern studies attribute to the quality of nutrition of modern man. The development of more and healthier foods by use of biological methods or the use of cultivation practices with less chemicals and fertilizers are a requirement in modern societies and markets. Still, the requirement for active reduction of chemicals and fertilizers creates problems in modern farming.
For Spain, Italy and Greece, one of the key crops of the primary sector (annual exports in first few positions of the corresponding exports table) is the olive and its products. The position of olive cultivation in Greece is also the result of specific market needs & the continuation of a tradition and a way of living for Greek olive oil producers. Accordingly, olive related holdings should be not assessed only from a purely economic point of view as are associated with many other non-economic factors that make this production sector a way of living.
Pests & diseases
However, the management of olive diseases is still being currently addressed with terms and practices of the past century, despite the plethora of modern technologies for monitoring and early warning of possible attacks. In particular, the pest olive-fruit fly is the most serious entomological enemy of olive is nowadays prevalent in all the olive-oil producing countries (Mediterranean & USA), causing huge losses every year. The pest’s presence seems to be spreading & in October 1998, the first recorded appearance of the fly was made in the USA and probably throughout North America. In Greece the pest is found in all the olive groves and is known since antiquity. The damage it can cause in the absence of control measures, can very easily reach levels of up to 80% of production.
The olive-fruit fly
The phenology and population density of the pest varies greatly from one region to another, depending on the ecological conditions of each region. During its biological cycle the olive fruit fly passes through stages: egg, larva, pupa, and perfect pest. In most locations, it displays 3-4 generations per year. The transhumance of the pest takes place in the soil. It can even be found during the winter in the olive groves as a fully developed pest in cases the climatic conditions are not prohibitive for its survival. So in areas with mild winters and when the olives are suitable for feeding the larvae of the pest it may be possible to have it present in all its biological stages. It should be noted that the large fruited varieties of olives with juicy flesh and the small trees or irrigated trees for production are usually affected earlier. The timing of the first attack for each olive variety differs from region to region and between years. The growth & development of the pest can reach 4-5 generations during the year. The need to find food & fruit susceptible to egg deposition requires a fully developed pest to fly distances reaching 4-10km.
Addressing the elephant in the room
It is therefore clear that tackling the olive-fruit fly is a very complex problem. The common method producers use, chemical applications, with total or partial coverage may be completely ineffective if the application (spraying) is not in the correct and optimal in time and place. To tackle the pest the chemical control is applied preventively and therapeutically. Unlike the therapeutic approach, the preventive, in order to be effective, is applied over large areas to prevent re-infection so it is organized by central organizations such as the Ministry of Agriculture with local farming directors. A prerequisite for the success of bait method (ground or air) is timely and meticulous implementation of the first spray that is decisive for the further course of the pest control since it coincides with foundation generation of the pest. IT is therefore, once again obvious, that the urgent need for reliable monitoring & prediction of the biological cycle of the pest has a great impact to its control.
The same principles are found in cases of application of alternative control methods. Indeed, methods such as biotech, growth regulators, symbiotic bacteria destruction and pests’ technical sterilization do exist. Still, a common denominator for the effectiveness of the above methods is the exact prediction of the biological cycle of the pest.