Plagues and diseases of the Olivar

Plague: Fly of the olive tree (Dacus oleae)

It is an insect of the family díptero of Tripétidos which is in the Mediterranean area, in western Asia and in many parts of Africa. This is a fly in that state adult measured 4 to 5 millimeters in length. The female just his abdomen with the device ovipositor, conical shape and a millimeter long, could distinguish easily tap.

The eggs are white and milky length of less than one millimeter, the larvae do not have legs, are so cilindrocónica its size and reach full development of 6 to 8 millimeters long by 1.3 to 1.4 millimeters wide.

Pupal His condition is so elliptical, with no larger than 0.5 mm long and 2 millimeters wide, acquiring a yellowish brown ochre at the beginning and thereafter.

1. iological cycle

   It spends the winter in state of pupa, under earth and with less frequency in adult state in protected sites. In spring (March - April) they appear the adults and they initiate a period in which they are fed on sweetened substances and nitrogenadas, necessary for the development of the genitals, that find in exudates of flowers, fruits, injuries or punctures and even in excretions of other insects (melazas of homopteros).

   The egg putting is realized in the olives, three days after the connection, the female chooses the fruits so that they at least have 8 or 10 millimeters of diameter and that they are not perforated previously.

   In the last generations the female even selects fruits whose state of maturity allows to synchronize its development with the evolution of the larva. Normally it has 3 generations to the year, although it can arrive at 4 in very favorable circumstances. The summer generations complete their cycle in 35 to 40 days, arriving up to 60 days in the autumnal generations.

2. Development of the Plague

   The climatic factors, temperature and humidity, influence decisively in the development of the plague, so that they limit his geographic area, regulating even their amplitude of the biological cycle. In Spain, the greater intensity of the plague occurs in the coast, where endemic the high existing relative humidity is given.

   To the interior the attacks of the fly are accidental more and they only take place when the climatic conditions are favorable. The high temperatures and the low relative humidity of the summer prevent the development of the insect since the eggs and larvae new born dry up. The nonprosperous plague therefore until the beginning of autumn, when the first rains take place. Inside the Peninsula the plague is not developed because the climatology is not to him favorable.

   Besides the climatic conditions, the variety of the olive tree and the predators of the fly are also influential factors in the development of the plague. The adults, in his first generations mince the advanced olives more, reason why the early varieties more are attacked at the outset. However in the last generations, the fly looks for the olives of delayed varieties, because they conserve more time green. On the other hand, the parasitic action of the predators of the Dacus is strong in summer, but in autumn it falls because at this time they are fed on other insects besides the fly larva.

3. Damages

   Dacus oleae considers one of the most important and frightful plagues of the olive tree. The adult fly puts its eggs in the fruit, and the larva is developed in the interior feeding itself of mesocarpio, bringing about in the olive a diminution of weight (20%) and considerable yield. The attacked fruits have clearest zones of the skin that the rest and as the olive is maturing, frequently they fall.

   The fall of the fruits and the diminution of weight and yield are the direct damages that the Dacus produces in the olive tree. But most important it is the indirect damage that it brings about the fly in the quality of the oil of the attacked olive.

   The larva, in its development originates in the fruits a great number of galleries and holes by where they penetrate fungi (Gloeosporium olivarum) and bacteria that seriously alter to the quality of oils because of the increase of acidity and the deterioration of the organoleptic characteristics.

4. Average of Fight

   The procedure to fight the fly is different according to the zone. In the Mediterranean coast one will begin to try when the olive has of 8 to 10 mm of size, whereas to the interior where the attacks are accidental it is more necessary to determine the population level to initiate the treatment.

   The control of the population levels is realized by means of mosqueros of crystal (McPhail type) in which introduces an biammonic phosphate dissolution to 3% or hidrolizable protein to 1%. They are placed inside the olive tree, with South direction and to average height. At times of rain, one is due to complete placing in the outside of the tree yellow plates attractive trap with sexual.

   When the number of flies picked up by mosquero is superior to 25, the treatments are due to initiate. Generally, for the first generations, one is due to try when the first minced olive is observed, agreeing with the formula fly/trap/day and alive larva. For the last generations, one is due to try when the coefficient of fly by mosquero and day is superior to 0,6.

   The treatment can take control of baits applied in the trees dunking a surface from 1 to 2 m2 in the part oriented to the south with a solution of 600 cc of dimetoato, 1 kg of hidrolizable protein and 100 liters of water.

   Also treatments in total pulverization can be done and in this case the insecticides will be used to normal doses. Also the use of formation, triclorfon, metidation and fosmet is recommended. Aerial treatments can be realized applying dose of 20 liters by total hectare of a dissolution composed by 0.5 liters of dimetoato, 0.5 kg of hidrolizable protein and 20 liters of water.

Plague: Barrenillo (Phoeotribus scarabeoides)

It is a coleopter of the family of the escolitidos ones, very common in all the olive-growing zones of the Mediterranean river basin. The adult is small escarabajo of one to three millimeters in length. The adult larvae reach up to four millimeters and the nymph looks like to the adult, but of milky white color. The eggs are oval, of size inferior to a millimeter and off-white color.

1. Biological cycle

   It spends the winter in state of adult and in spring an orifice goes to the pruning firewood, abriendo that extends in a camera where the connection takes place. Later the female abre a gallery to both sides of the camera and realizes the putting. Once the larvae leave, these make perpendicular galleries to the maternal one, and the end they become nymphs. The adults of the first generation abren nutricias galleries in the base of the bud or an axillary yolk and bring about their death. This usually happens in the month of June. The adults of the second generation appear in September, so that some hibernate and others mate to give one third generation in November and that it hibernates in adult state. Exceptionally one fourth generation can happen.

2. Damages

   It is necessary to consider that barrenillo reproduces in the firewoods coming from the pruning of the olive tree, reason why the attacks are majors in zones next to populations to field houses where the firewoods keep from pruning. The adult moves the trees and abre nutricias galleries in the one small branches to three years, as much in floral small branches as in which they have fruit. These galleries cut the passage of the sap and bring about the death of the branch. Independent of the effect in loss of harvest that produces barrenillo, the adults of the last generations bring about the premature fall of fruits influencing in the elevation of the acid value of the oil, as much greater at the most time remain the olives in the ground, producing to the oil flavors nonwished.

3. Average of Fight

   Barrenillo is quite difficult to fight directly since through its form of life it happens most of the time inside galleries. Most recommendable it is the indirect fight burying the pruning firewoods or treating the leñeras to avoid the propagation of the plague. He is advisable to prune the attacked branches and to burn them.

   For the treatments formation can be used, dimetoato or metidation. As it fights direct, they are due to leave some woods of pruning like witness and, agreeing with the exit of the adults of these woods, to do the treatment with metadion giving two or three applications and repeating with intervals of 15 days.

Plague: Prays of the Olive (Prays oleae)

The adult is small silver gray silverplated with dark spots that 13-14 mm of spread measures eave and about 6 mm of long. Wings with flecos. The biconvex egg, squashed, measures about 0.5 mm of diameter, is of off-white color just position and turns to yellowish as it is incubated. The caterpillar of 7-8 mm in its maximum development, is of color countersinks, although it can vary and dark head.

1. Biological cycle

   It has three synchronous generations to the year with the culture of the olive tree:

   1. Filófaga. The eggs are placed between October and November in the bundle of leaves and close to the midrib. The newborn larvae penetrate directly inside the sheet conducting a gallery where winding pass the winter. In the months of February and March and resumed their activity, making galleries circular, oval or rectangular. In stage 5 rises and falls in the lower side of the road, feeding on the buds terminals outbreaks. It forms a silky cocoon where the adult emerges in April.
   2. Antófaga. The adult generation filófaga engaged in the making flower buds. The larvae penetrate inside and feeds on the anthers, stigmas and ovaries of the flower.
   3. Carpófaga. Butterflies of the previous generation engaged in putting the olive newly curd (June). The larvae at birth penetrate the insertion of stem causing the fall of fruit. They are installed inside the fruit, between the bone and almonds, feeding on it. The larvae mature leaves through which entered the chrysalis and performs between two sheets in the trunk or on the floor.

2. Damages

   According to the generation of the insect they are different in:

   1. Filófaga. Damage to the leaves. There are important in the trees but developed in young people and damaging the leaves and shoots.
   2. Antófaga. Cause Damage in various flowers as years of the pest population, destination of the fruit (table or oil), etc.. It reduces the rate of fraught with flowers.
   3. Carpófaga. They are very important because there is a drop off. This drop occurs in June when the larva enters the fruit and in September when it comes out of it.

3. Methods of fight

   There are two clear moments of action:

   1. At the beginning of the flowering. Period in which the larvae are in the outside.
   2. CWhen the larvae are introducing themselves in the fruit.
      Products: B. thuringirnsis, dimethoate, Trichlorfon, methidathion, Carbanilides, diazinon, chlorpyrifos, etc.

Plague: Cotton of the Olive (Euphyllura olivina)

It is a very common insect in all Mediterranean countries and affects only the olive tree. Adults are small, thick and green. The eggs are so small elliptical, 0.3 mm and carried a small stalk that serves to set the olive tree. The globus larvae are yellow or pale ochre, crushed. Secrete a white wax that covers completely the larval colonies and that gives the appearance characteristic of cotton, which is known species.

They have two to three generations per year, causing various damage:

• In larvario and adult state it is a sucking insect of made sap what takes to an alteration of the normal development of the vegetable.
• Damages in the yolks that jeopardize the development of the tree.
• Damages in the inflorescencias, affecting to the fertility and fall of floral bellboys, which is translated in a diminution of dumbfounded fruits.

They are not recommendable treatments, except for cases in which the population surpasses the threshold of 10 insects by inflorescencia. In this case applied organofosforados products by means of terrestrial pulverizations will be used, wetting the tree for one more a more homogenous distribution well.

Plague: Cochineal of tizne (Saissetia oleae)

Very extended by all the Mediterranean River basin, it affects to the olive tree and the citruses, preferring shaded and ambient zones humid. The cochineal sucks sap and excretes numerous sweetened substances (molasses) that impregnate the olive tree and that in humid periods serves as food to black fungi (bold or fumagina) that the vegetal weaves cover as if it was a felt, falling the photosynthesis and the breathing.

The damages caused by this cochineal are:

• Direct damages: They are not important.
• Damage indirect: reducing the photosynthetic capacity of the tree, which leads to a decrease in the budding and in production.

Treatments:

• Natural enemies. Small wasps (hymenopterans), which deposit their eggs inside the cochineal feeding the body of this and eggs.
• The prunings facilitate the ventilation of the glass of the tree which repels negatively on the development of the immature states of the cochineal, since these are very sensible to the heat and the dry wind.
• Treatment chemicals in the summer when they eclosionados 100% of the eggs. This will involve a weekly monitoring of the populations of adults, eggs and larvae to determine the optimal time to treat.

Disease: Repilo of the Olive (Cycloconium oleaginym Cas.)

Repilo is a disease produced by the Cycloconium fungus oleaginum and is considered as the micosis of the extended olive tree more in all the regions of Spain and the rest of the olive-growing countries. The most important consequence constitutes the intense defoliation of the hoisted one, with the consequent weakening and the diminution of the productivity.

1. Symptoms and damages

   The most characteristic symptom is the appearance in the beam of the leaf of circular spots of variable size and showy coloration. Initially these injuries are of dark color, but soon after they are surrounded by I pull ahead yellowish and the central zone of La Mancha also takes a yellow tonality. Later it returns to darken itself, when being developed envelope she them fruitful bodies of the fungus (conidias).

   Sometimes the injury presents a whitish tone, due to the separation of the cuticle and skin. The development of spots in the beam is not matched by similar demonstrations in the lower side, where sometimes only be seen intermittent blackened areas along the midrib.

   They are less frequent injuries caused by the disease in the petiole of the leaves, stem to the fruit and the fruit. In this case the spots are dark brown hue and elongated shape.

   As a result of these injuries is a fall leaf important leaf, which can be seen clearly in the trees, and especially in the low branches, which are most affected by the disease and can be completely defoliation. When the lesion is located in the area of the fruit stalk, which is not very frequent, it falls prematurely, accompanied by a piece of stem.

2. Biology

   The fungus survives in unfavorable periods for its development in the fallen leaves and the affected leaves that remain in the tree, being able to propagate the disease the year throughout, but the most frequent periods of infection are September - November and February - April.

   The evolutionary cycle of repilo has four distinct phases:

   1. Germination. It needs free water on conidia and the zone penetration in the receiving weave and temperatures between 8 and 24º C, with an optimal temperature of 20º C.
   2. Infection. After the penetration the mycelia of the fungus are developed intracellularly that grow Inter and in the CAP of more external epidermoid cells and follow their contour. The first infections agree with the period of rains of the end of the summer or principles of autumn, moment at which the disease from conidias is developed initially which they have survived the summer.
   3. Sporulation. The is the appearance on the outside of the leaf or fruit-body conidia, which spread the disease.
   4. Dissemination. Conidias disperses almost exclusively in the rain, that's why the excessive infections take place preferably in descendant sense in the tree and that the low zones are affected.

3. Measures recommended for its fight

   Given the diversity of the Spanish olive grove, the general strategy of prevention and it fights can vary according to the different zones, reason why it is advised to follow the indications of the corresponding Station of Warnings.

   • Cultural measures:
     Given the great importance of high humidity and free water in the development of the disease, are recommended measures that promote cultural aeration and reduce condensation, such as pruning to avoid crown dense and highly populated. In endemic areas is recommended choosing varieties less susceptible to infection: Acebuche, Zorzaleña, Lechín, Picual, Hojiblanca, Manzanilla, Gordal, Cornicabra.
   • It fights Chemical:
     The optimal moments of treatment both correspond to classic periods of the end of the summer or principles of autumn and end of winter.

     In sensible varieties or endemic zones, with infections of repilo in high summer (more of 30-40% of leaves infected), it is necessary to try before rains of end of summer or beginning of autumn take place and to repeat this treatment in the following spring.

     If the summer infection were low (less than 10% of affected leaves), the treatment can be delayed until the appearance of new spots esporuladas in the leaves and just by this application usually is sufficient to prevent the disease.
     Since the treatments are preventive, all the foliar mass of the tree is necessary to wet with the broth fungicide preferably very well and the low and inner zones, that are where more frequently the disease is developed.

     Products fungicides: Caldo Bordeaux, copper oxychloride (50% Cu), copper oxychloride (37.5%) and Zineb (15%), cuprous oxide (50% Cu), Captan, captafol, Ziram, Benomyl (systemic properties curative), and so on.

     There are some measures that can contribute to the effectiveness of the fight against repilo and that agrees to have presents:

     1. Not to use sprays nor systems of pulverization that produce very small drops. A pressure of recommendable work is the one of 40 atmospheres when coming out of the tank.
     2. In treatments before harvesting in autumn, it is not advisable to use products containing fungicides carbamates (zineb, maneb, etc.) to avoid waste problems in the oil. The term security products cúpricos is 15 days.
     3. Not to realize treatments in summer, except in very humid zones, since at this time the fungus is inactive and agrees to save products and to reduce expenses.
     4. To try, by means of the pruning, to form ventilated glasses of good olive tree.
     5. Not abusing nitrogenous fertilizers, both organic and chemical.

Disease: Olive Soap (Gloeosporium olivarum)

It is a Deuteromiceto fungus that attacks the fruit essentially although sometimes also it can appear in leaves, wood and I appear.

The invasion of Gloeosporium usually takes place around the month of September. The first symptoms pronounce by means of an oily ocher spot around the entry point of the infection, producing later conidias of pink color, in concentric zones. The infection therefore can take place in still green fruits or when they change of color and at moments near the maturity, based on the variety.

One is a typical damage of rainy years, because the fungus to be developed needs a humidity relative superior to 90% and one temperature around 25º C, although to temperatures inferiors also take place damages.

The germination of the fungus is very fast and can complete its cycle, under optimum conditions, within 10 days. He spends the winter in the fruits fallen to the ground, causing reinfections the following year at the time that conditions are optimal.

1. Damages

   After the infection of the fruits, in the caused spots they appear conidias that they secrete a gelatinous substance of yellowish color, initially and brown later. The attacked parts are cork-like and the momifica fruit, spoiling the skin. Consequently the olive falls, low the yield remarkably and the oil that takes place of these fruits reaches a very high acidity.

2. Average of fight

   The products cúpricos give good results. The broth Bordeaux 2% or mixtures of copper oxychloride to 37% more zineb 15% to 0.4%, adding mojante if the product is not what leads are the most commonly used.

   The treatments are preventive, so that when damage is anticipated, a treatment in September is due to do (combined with some other for fly, etc.) and to repeat more ahead if there are rains or it is an endemic zone.

Disease: Escudete (Macrophoma dalmática)

Disease that attacks the olive, producing an almost circular spot, dark and of half centimeter of diameter, seemed to escudete, from where it takes his name. She is typical of the olives for verdeo, that when presenting/displaying to these makes unusable them injuries for such aim.

Sometimes the olives take forms similar to the Gloeosporium, but the spots are distinguished by the existence of picnidios in the form of black points, that are not confused with the acérvulos of pink color of the Gloeosporium.

From the point of view of the quality of the oil, the damages are the typical ones of all those alterations that affect the pulp or bring about fruit fall, that always is translated in high acidity, strange flavors and sometimes difficulties in the elaboration.

It is a disease little extended generally, but one appears is a concrete zone or in determined years, it is recommended to act of the same form that with the soapy olive.

Disease: Tubercolosis of the Olive (Pseudomonas savastonoi)

The tuberculosis is produced by a bacterium of the order of the Eubacteriales. One is an alteration very extended in the Spanish olive grove and depends much on varietal sensitivity, among others causes.

The bacterium penetrates in the olive tree through wounds produced generally by the pruning, the harvesting, the hail or the frosts.

When some of these circumstances occurs or the combination of them and a variety is sensible, the bacterium extends of a spectacular way. The propagation becomes through rainwater, the rubbing of the branches by the wind, or the instruments of pruning, mainly.

1. Damages

   The tuberculosis is characterized by the appearance of tumors that at first are small, soft, smooth and of green color. Later they are lignifican and they hardened presenting/displaying an irregular, rough and cracked surface. Its size, once reached the total development, is similar to the one of a hazelnut, and can be isolate or very next an a others.

   When the attack is strong can bring about the weakening and drying of many attacked branches, even the own tree. The attacked olive trees produce fruits of very bad quality, little harvest and frequently the olive falls to the ground for want of nutrition. The obtained oils are of little yield and with strange flavors.

2. Average of fight

   It is necessary to take preventive attitudes, because once installed the bacterium in the olive grove, turns out complicated and expensive to eliminate it.

   For the harvesting he is preferable not to use average traumatic like the vareo, that produces many wounds. Of interest order it would be in favor the vibrator, when it can, or the milking by hand helped of small nontraumatic instruments.

   When carrying out the pruning the olive trees affected for the end are due to let, avoiding transmit the bacterium to the healthy trees. The pruning instruments must become disinfected passing them through a flame or by means of its introduction in concentrated ferrous sulfate dissolutions.

   Vegetal material for multiplication, of infected plantations is not due to use.

   An effective method is to cut and to burn in the same field all the attacked branches, preferably in dry time since the humidity favors the infection.