At Agro Vivero del Mediterráneo, we have spent years dedicated body and soul to the fascinating world of the pistachio. Our experience is not measured in time, but in the quality of each pistachio plant that leaves our nurseries and in the success of the plantations we advise. We understand that the path to an abundant and superior quality harvest is full of challenges, and one of the most important is, without a doubt, pest management. 🐛🐞

Throughout our trajectory, we have seen how small invaders can jeopardize the profitability of a plantation if one does not act with knowledge and precision. That is why we have decided to share our experience and knowledge in this comprehensive guide on the most common pests in pistachio plantations and, most importantly, how to keep them at bay. It is not just about applying treatments, but about understanding the behavior of each insect, knowing its life cycle, and applying Integrated Pest Management (IPM) strategies that are effective, sustainable, and respectful of the environment and auxiliary fauna, that great ally of the farmer.

Our goal at Agro Vivero del Mediterráneo is to accompany farmers at every step, from choosing the plant to harvesting the precious nut. We consider training and information to be tools as vital as the best tractor. Prepare to immerse yourself with us in the universe of pistachio plant health. We are going to break down, one by one, the main threats lurking in our plantations, offering practical and proven solutions that we have perfected over the years. Because an informed farmer is an empowered farmer, and in protecting our plantations, knowledge is the first line of defense.

The Pistachio Psylla (Agonoscena pistaciae)

We begin with what, for many, is the key and most feared pest in pistachio plantations: the Psylla, scientifically known as Agonoscena pistaciae. This small insect, which at first glance may seem harmless, has the potential to cause very significant damage, affecting both the current year’s production and the plant’s development for future harvests. At Agro Vivero del Mediterráneo, we have dedicated countless hours to its study and control, and we know that prevention and early action are crucial.

The Psylla is a small homopteran, between 1.5 and 2 millimeters long in its adult state, with a color ranging from greenish-yellow to reddish-brown. Its appearance is similar to that of a small cicada. However, the real problem lies not so much in the adult as in its nymphs. These are the ones that cause direct damage by feeding on the sap of tender shoots, leaves, and pistachio clusters.

The biological cycle of the Psylla is a determining factor for its control. It spends the winter in the adult state, taking refuge in the bark of trees, in fallen leaves, or in the spontaneous vegetation of the surroundings. With the arrival of spring and the rise in temperatures, generally from March onwards, adults regain their activity, mate, and females begin laying eggs on the underside of newly sprouted leaves. Each female can lay up to 500 eggs, which gives us an idea of its incredible multiplication potential. Throughout the season, depending on climatic conditions, between 5 and 7 generations can occur, overlapping with each other. This means that during spring and summer we can simultaneously find adults, eggs, and nymphs in different stages of development in the plantation.

The damage caused by the Psylla is of various kinds. The main and most visible one is the secretion of abundant honeydew, a sugary and sticky substance that impregnates leaves, shoots, and nuts. This honeydew has several negative consequences:

1. Reduction of photosynthetic capacity: Honeydew acts as a screen that hinders the capture of sunlight by leaves, thus reducing photosynthesis. Deficient photosynthesis translates into less plant development, poor nut filling, and less accumulation of reserves for the following year. 📉

2. Appearance of sooty mold: On this honeydew, a fungus known as sooty mold or fumagina (Capnodium spp.) develops. This black fungus covers the affected parts of the plant, aggravating the reduction of photosynthetic capacity and staining the pistachios, which can depreciate their commercial value.

3. Burns and defoliation: The combination of sap sucking by nymphs and the presence of honeydew and sooty mold greatly weakens the leaves. In severe attacks, leaves wrinkle, turn yellow, dry at the edges (known as “chlorotic stippling”), and can fall prematurely. Early defoliation seriously compromises the current harvest and the formation of flower buds for the next campaign.

4. Attraction of other insects: Honeydew is a food source for other insects, such as ants, which in turn can protect the Psylla from its natural predators, creating an imbalance in the plantation ecosystem.

For the control of the Pistachio Psylla, at Agro Vivero del Mediterráneo we always advocate for an Integrated Pest Management approach. This implies a combination of different strategies that go beyond the simple application of insecticides.

Monitoring and tracking: It is the cornerstone of any control strategy. From the beginning of budding, we carry out weekly samplings to detect the presence of adults and the first egg layings. An effective technique is the “beating method,” which consists of hitting a branch over a tray or white cardboard to count the adults that fall. It is also essential to check the underside of leaves, especially apical ones, to locate eggs and the first nymphs. Establishing a treatment threshold is vital. Generally, we recommend acting when a certain percentage of leaflets occupied by living forms (nymphs) is exceeded. This threshold may vary according to the time of year, the state of the plantation, and the presence of auxiliary fauna.

Cultural control: Certain practices in plantation management can help us prevent or reduce the incidence of Psylla.

• Balanced fertilization: Excess nitrogen causes exuberant and tender vegetative growth, which is preferred by the Psylla. Therefore, we recommend a fertilization plan adjusted to the real needs of the plant, based on soil and foliar analyses.

• Cover crop management: A well-managed cover crop can harbor important natural enemies of the Psylla. It is preferable to keep it mowed at an appropriate height rather than eliminating it completely with herbicides.

• Proper pruning: Pruning that favors aeration and light penetration into the interior of the tree creates a less favorable microclimate for pest development and facilitates the arrival of phytosanitary products to all parts of the plant.

Biological control: Nature is our great ally! 🌿 There are numerous predators and parasitoids that feed on the Psylla. Encouraging their presence is a smart and sustainable strategy. Among the most important predators we find:

• Anthocorids (genus Anthocoris): They are very voracious predatory bugs, both in nymph and adult stages.

• Lacewings (Chrysoperla carnea): Their larvae are very effective generalist predators.

• Coccinellids (ladybugs): Both adults and larvae feed on Psylla nymphs.

• Syrphids: The larvae of these “flower flies” are also excellent predators.

To enhance this auxiliary fauna, we recommend installing hedges or floral strips on the margins of the plantation with plant species that provide them with shelter and alternative food (pollen and nectar). Species such as borage, fennel, marigold, or phacelia are excellent options.

Chemical control: When pest levels exceed the treatment threshold and biological control alone is not enough, it is necessary to resort to chemical control. The choice of product and the timing of application are determining factors for its effectiveness and for minimizing the impact on auxiliary fauna.

• Winter treatments: In plantations with a history of severe attacks, a winter treatment with paraffin oil, sometimes mixed with an insecticide, can be considered to reduce populations of overwintering adults.

• Treatments in vegetation: It is crucial to choose active ingredients that are respectful of natural enemies. Some products that we have verified work well and are relatively selective are abamectin, spirotetramat, or potassium salts (potassium soap), which act by contact and have a honeydew washing effect. Azadirachtin, extracted from the Neem tree, is also a good option in organic farming due to its growth-regulating effect. It is fundamental to alternate active ingredients with different modes of action to avoid the appearance of resistance. The optimal time for treatment is usually when the first nymphal stages predominate, as they are the most sensitive.

In short, managing the Psylla is not a simple task, but with constant monitoring, an integrated approach, and the advice of our experts, it is possible to keep its populations below the economic damage threshold, ensuring the health of our plantations and the quality of the harvest.

Pistachio Bugs (Various species)

Another group of insects that gives us headaches in pistachio plantations are bugs. It is not a single species, but a complex of hemipterans from different families (mainly Pentatomidae, Miridae, and Lygaeidae) that have in common their piercing-sucking mouthparts, with which they pierce plant tissues to feed. Their damage can be devastating, directly affecting the quality and quantity of the harvest.

These insects usually spend the winter as adults in protected shelters, such as leaf litter, tree bark, or adventitious vegetation. With the arrival of good weather, they become active and move towards pistachio plantations, attracted by the development of nuts.

The most characteristic and serious damage they produce is the pistachio stain or “stigmatomycosis”. This damage occurs when bugs bite the developing nut to feed on the seed. In doing so, they not only suck its contents but can also inoculate fungi of the genus Nematospora or Eremothecium, which they carry on their stylet. This infection causes necrosis of the seed tissue, which acquires a dark color and a spongy consistency, becoming unfit for consumption. A nut affected by stigmatomycosis cannot be distinguished externally from a healthy one until it is opened. This poses a very serious problem, as a high percentage of damaged nuts can cause an entire batch to be rejected by the processing industry.

In addition to stigmatomycosis, bug bites can cause other problems:

• Premature nut drop: If the bite occurs in the early stages of development (fruit set and initial growth), it can cause the small nut to fall.

• Deformations and external stains: Sometimes, the bite can generate small necrotic spots or deformations on the outer shell, although the main damage remains internal.

• Yield reduction: Direct sucking of nutrients from the seed can result in lower weight and size of the nut.

Some of the most common bug species found in pistachio plantations in the Iberian Peninsula are:

• Nezara viridula (green stink bug): One of the most polyphagous and recognizable.

• Pistaciae bug (Pistaciae spp.): Species more specific to the genus Pistacia.

• Lygaeus equestris: A bug of the Lygaeidae family, often associated with spontaneous vegetation.

• Calocoris norvegicus: A mirid that can also cause significant damage.

Controlling pistachio bugs requires a vigilant and proactive strategy.

Monitoring: As with the Psylla, monitoring is fundamental. Bugs are mobile and often elusive insects, which can make their detection difficult. Direct visual inspection of clusters is important, but often insufficient. The beating method on a tray or white cloth can be useful to detect their presence. The critical time for monitoring and control is during the seed development period, which spans approximately from late May to late July.

Cultural control:

• Management of adventitious vegetation: Many bug species reproduce and take refuge in weeds within the plantation itself or on the margins. Controlling this vegetation, especially during spring and before the critical period of nut development, can significantly reduce bug populations that later move to the trees. It is especially important to control plants of the crucifer and composite families, which act as alternative hosts.

• Removal of pruning remains: Do not leave pruning remains in the plantation, as they can serve as shelter for overwintering adults.

Biological control: Bugs also have natural enemies, such as egg parasitoid wasps (for example, of the genus Trissolcus) and some generalist predators. However, in many cases, biological control alone is not capable of keeping populations below the economic damage threshold, especially in years of high pest pressure. The conservation of these natural enemies, however, is always a recommended practice and is achieved by avoiding the use of broad-spectrum insecticides.

Chemical control: It is the most used tool for bug control, but it must be used judiciously.

• Application timing: Treatment should be directed against adults before they lay massive eggs on the trees and, above all, during the period of maximum susceptibility of the nut (when the seed is in its “milky” phase and is most appetizing to them). Performing treatments early in the morning or at dusk, when bugs are less active, usually improves effectiveness.

• Product choice: There are various active ingredients authorized for bug control in pistachio. Pyrethroids such as lambda-cyhalothrin or deltamethrin are effective, but great care must be taken with them, as they are not very selective and can eliminate auxiliary fauna, causing the appearance of other pests such as red spider mite. Other more respectful options can be active ingredients such as acetamiprid or sulfoxaflor, always consulting the official register of phytosanitary products and respecting safety periods.

• Perimeter treatments: Often, bugs enter the plantation from the margins. An interesting strategy can be to carry out treatments in the first rows of trees on the perimeter of the plot to create a barrier and stop their entry.

In our experience, the key to controlling bugs lies in good management of spontaneous vegetation and exhaustive monitoring during the critical phase of nut development to be able to intervene at the precise moment and with the right product. A harvest clean of stigmatomycosis is synonymous with a high-quality harvest and, therefore, greater profitability. If you have doubts about how to manage this pest, do not hesitate to contact us.

The Almond Lace Bug (Monosteira unicostata)

Although its common name refers to the almond tree, the Lace Bug (Monosteira unicostata) is another pest that can seriously affect pistachio plantations. This small insect, a heteropteran of the Tingidae family, owes its name to the dark spots on its wings, which resemble the skin of a tiger. It is small in size, barely 2-3 millimeters, and has a flattened body.

The Almond Lace Bug causes damage by piercing leaves to suck sap from parenchyma cells. The bites cause the appearance of a multitude of small chlorotic spots, yellowish or whitish in color, on the upper side of the leaves. If the leaf is turned over, on the underside, adults, nymphs (which have no wings and are darker in color), and characteristic shiny black spots, which are their excrement, can be observed.

A strong Lace Bug attack produces generalized discoloration of the leaf mass. Leaves acquire a leaden or silvery appearance and, in very severe cases, can dry out and fall prematurely. This damage, like that caused by the Psylla, has negative consequences:

• Reduction of photosynthesis: The destruction of parenchyma cells decreases the leaf’s ability to perform photosynthesis, which results in lower tree vigor.

• Weakening of the tree: A weakened tree is more susceptible to other pests and diseases.

• Lower nut filling: The lack of assimilates directly affects the caliber and weight of pistachios.

• Impact on future harvest: Premature defoliation prevents the tree from accumulating the necessary reserves in buds for budding and flowering the following year.

The biological cycle of the Almond Lace Bug is similar to that of other summer pests. It spends the winter as an adult, sheltered in the tree bark or leaf litter. In spring, adults regain activity and females lay eggs inside the tissues of the underside of leaves. They can have several generations throughout the year, generally 3 to 4, with populations being highest during the summer months, especially in July and August, coinciding with high temperatures. Dry and hot summers greatly favor their development. ☀️

Lace Bug control must be approached, once again, from an Integrated Management perspective.

Monitoring: From spring onwards, it is necessary to carry out periodic inspections of the underside of leaves to detect the presence of the first adults and their eggs. It is a pest that is usually distributed by patches or foci within the plantation, so it is important to check trees in different areas of the plot. The treatment threshold is usually established based on the percentage of affected leaves and the number of mobile forms per leaf.

Cultural control:

• Adequate irrigation: Plantations with water stress are much more sensitive to Lace Bug attacks. Correct irrigation management, ensuring that the plant does not suffer stress during the summer months, helps the tree tolerate the pest better.

• Pruning: Good pruning that facilitates aeration can create a less favorable microclimate for its proliferation.

Biological control: Fortunately, the Almond Lace Bug has natural enemies that can help control its populations. Mainly predatory bugs of the Anthocoridae and Miridae families. The conservation of these auxiliaries through the use of selective insecticides is a fundamental practice.

Chemical control: If monitoring reveals that the treatment threshold has been exceeded, chemical intervention will be necessary.

• Application timing: Treatment should be carried out when the first colonies are detected and before populations skyrocket. It is important to wet the underside of the leaves well, which is where the pest is found.

• Product choice: There are several effective and authorized active ingredients. Potassium salts (potassium soap) can be a good option to wash leaves and act by contact, especially with low pest levels. Natural pyrethrins or azadirachtin are valid alternatives in organic production. In conventional production, products such as acetamiprid, spirotetramat, or pyrethroids (used with caution due to their impact on auxiliary fauna) can offer good control. It is crucial to always consult the register of products authorized for the crop.

At Agro Vivero del Mediterráneo, we have observed that young plantations, such as those started with our high-quality pistachio plant, can be especially sensitive to the Lace Bug. Therefore, in the first years, vigilance must be maximum to ensure correct tree development and structure formation.

Bark Beetles (Scolytus spp. and others)

Bark beetles are a group of small beetles (coleopterans) of the scolytid family that represent a very serious threat, especially for weakened, stressed, or young trees. Unlike previous pests that mainly attack leaves and nuts, bark beetles attack wood, boring galleries under the bark of the trunk and branches. Their action can cause the death of entire branches and even the entire tree.

The most common species affecting the pistachio tree are Scolytus amygdali and Scolytus rugulosus. They are small insects (2-3 mm), dark in color, almost black, and cylindrical body.

Damage is caused by both adults and larvae. Adults bore an entry hole in the bark and construct a maternal gallery under it. On both sides of this gallery, the female deposits eggs. When larvae hatch, they begin to excavate their own galleries, perpendicular to the maternal gallery. These larval galleries widen as the larva grows. All this network of galleries interrupts the flow of sap through the phloem and xylem vessels, causing girdling of the affected branch or trunk.

Symptoms of a bark beetle attack are very characteristic:

• Presence of small round holes in the bark, similar to those made by a pellet. These are the entry and exit holes of adults.

• Exudation of gum or resin at attack points, a defense reaction of the tree itself.

• Fine sawdust accumulated at the base of the trunk or in bark cracks, result of gallery excavation.

• Progressive weakening of the affected branch: leaves turn yellow, wither, and finally the branch dries out.

• If the bark of an affected branch is lifted, the typical gallery pattern can be observed.

It is fundamental to understand that bark beetles are, largely, secondary pests. This means that they preferentially attack trees that already present some type of weakness or stress, such as water stress, nutritional deficiencies, frost damage, severe pruning, or diseases. A healthy and vigorous tree is capable of defending itself from initial attacks by secreting resin that drowns insects attempting to pierce the bark.

The biological cycle of bark beetles begins in spring, when adults that have overwintered in galleries emerge and fly in search of new trees to colonize. They can have 2 to 3 generations a year, so the risk period extends throughout spring and summer.

Bark beetle control is based, above all, on prevention. Maintaining the plantation in optimal sanitary and vigor status is the best defense.

Prophylactic and cultural measures (the most important!):

1. Proper irrigation and fertilization management: Avoid any type of stress on the plant. A well-nourished and hydrated tree is the first barrier against bark beetles.

2. Correct pruning: Perform balanced pruning, avoiding drastic cuts that weaken the tree. It is crucial to remove and immediately destroy all affected pruning wood. Never leave pruning remains in the plantation! 🪵🔥 Pistachio wood piled on the margins of the plot is a prime breeding and dispersal focus for bark beetles. Pruning remains must be burned (always with relevant permits) or shredded as soon as possible.

3. Removal of weak or dead trees: Sanitize the plantation by removing any tree or branch that is heavily affected, as they act as reservoirs for the pest.

4. Trunk whitewashing: In young plantations, whitewashing trunks with lime or protective paste can have a deterrent effect on adults.

Chemical control: Chemical control against bark beetles is complicated and often ineffective, as larvae are protected under the bark. Treatments must be directed against adults during their flight period, before they bore into the wood.

• Flight monitoring: To determine the optimal treatment time, it is essential to place monitoring traps. Interception traps baited with ethanol, which acts as an attractant for adults, can be used. When the start of the flight peak is detected, it is time to act.

• Insecticide treatments: Trunks and main branches should be sprayed with an authorized contact insecticide. It is a “painting” or “smearing” treatment rather than a foliar spray. Active ingredients such as deltamethrin or lambda-cyhalothrin can be effective. However, their persistence is limited, so it may be necessary to repeat the treatment if flights are prolonged over time.

• Mass trapping: In plots with high pest pressure, a mass trapping strategy can be considered, placing a larger number of traps per hectare to capture as many adults as possible and reduce populations.

Our recommendation from Agro Vivero del Mediterráneo is clear: the best investment against bark beetles is to maintain a strong and healthy plantation. Dedicating efforts to good agronomic management is much more profitable and sustainable than relying on curative chemical treatments which, in the case of this pest, have limited effectiveness. If you detect symptoms of bark beetle, act fast, sanitize the plantation, and consult us to establish a shock plan.

The Pistachio Moth (Plodia interpunctella)

Although often associated with stored products, the Indian Meal Moth (Plodia interpunctella) can also be a problem in the field, especially in the final phase of pistachio ripening and during post-harvest. It is a pest that directly affects the product we are going to market, so the damage it causes is purely economic.

The adult moth is small, about 8-10 mm long, and easily recognizable. The anterior third of its wings is pale gray, while the posterior two-thirds are a characteristic coppery or bronzed color. They are nocturnal, so it is difficult to see them during the day.

The real problem is the larvae. Females deposit their eggs on pistachios that have opened their shell prematurely on the tree (known as “split”). When the larva hatches, it penetrates inside and feeds on the seed. During its development, the larva produces a large amount of silk threads, excrement, and molting remains, contaminating and destroying the nut. A single affected nut can contaminate those around it, especially during storage. 🐛

Damage is concentrated at two key moments:

1. In the field: Just before harvesting. Varieties that tend to have a higher percentage of early “splits” are more susceptible. The larva can complete part of its development inside the pistachio while it is still on the tree.

2. In the warehouse: This is the main battlefield against Plodia. If harvested pistachios carry eggs or small larvae, these will continue their development in the warehouse, infesting the rest of the harvest. Warehouse temperature and humidity conditions are usually ideal for their rapid proliferation.

Controlling the Pistachio Moth requires meticulous attention both in the field and, above all, in post-harvest facilities.

Field control:

• Early and rapid harvesting: Not delaying harvest is fundamental. The longer ripe pistachios remain on the tree, the greater the probability of being infested. Once harvested, they must be transported quickly to the processing plant.

• Monitoring with pheromone traps: Placing traps with specific sex pheromones for Plodia interpunctella allows us to detect the presence of adults in the plantation and know their population level. This helps us assess risk and decide if any action is necessary.

• Chemical control in the field (uncommon): Generally, specific treatments against the moth are not carried out in the field, as it is difficult to reach larvae protected inside the pistachio. In addition, proximity to harvest greatly limits the use of insecticides due to safety periods. Preventive measures are much more effective.

Post-harvest and warehouse control (key):

1. Exhaustive cleaning: Before introducing the new harvest, the warehouse and all machinery (trailers, conveyor belts, dryers, etc.) must be thoroughly cleaned. All remains of previous harvests, dust, and cobwebs must be removed, as they can harbor pupae or larvae. Hygiene is the first barrier! 🧹

2. Rapid processing: Rapid peeling and drying of pistachios after harvesting eliminates many eggs and small larvae. The drying process, with hot air, also contributes to reducing pest viability.

3. Warehouse monitoring: Placing pheromone traps also inside the warehouse is crucial to detect any infestation early.

4. Storage conditions: Storing pistachios at low temperatures (below 10-12 °C) and with low relative humidity greatly slows down or even stops moth development.

5. Warehouse treatments: If an infestation is detected, there are several options:

   • Controlled atmospheres: Storing pistachios in airtight silos where the atmosphere can be modified, reducing oxygen level and increasing carbon dioxide, is a very effective and clean method to eliminate all pest stages.

   • Phosphine: Fumigation with aluminum or magnesium phosphide (which releases phosphine gas) is a very effective treatment, but must be carried out by qualified and authorized personnel, as it is a very toxic gas.

   • Diatomaceous earth: In organic farming, grain can be mixed with diatomaceous earth, an inert powder of fossil origin that acts by contact, adhering to the insect and causing its death by dehydration.

For us, post-harvest management is an integral part of the services we offer. It is useless to produce excellent quality pistachio in the field if it later spoils in the warehouse. Correct management of the Pistachio Moth is vital to guarantee food safety and harvest value.

Mites (Red and Yellow Spider Mite)

Tetranychid mites, commonly known as red spider mite (Tetranychus urticae) or yellow spider mite (Eotetranychus spp.), are another recurring concern in our plantations. They are not insects, but arachnids of tiny size, almost imperceptible to the naked eye, that develop on the underside of leaves. Their presence is usually linked to conditions of heat and low ambient humidity, so dry summers are their time of maximum splendor.

These mites feed by piercing leaf plant cells to suck their contents. These countless bites cause the appearance of very fine chlorotic stippling which, seen as a whole, gives the leaf a dusty appearance and a yellowish or coppery color. In strong attacks, leaves dry out and fall prematurely. A characteristic sign of red spider mite presence is the formation of fine cobwebs on the underside of leaves, which serve as protection. 🕸️

The damage they produce is very similar to that of other foliar pests such as Psylla or Lace Bug:

• Drastic reduction of photosynthetic capacity.

• Premature defoliation, especially in summer months.

• Lower caliber and weight of the nut.

• General weakening of the tree and less accumulation of reserves for the next campaign.

One of the main causes of mite outbreaks in plantations is the indiscriminate use of broad-spectrum insecticides, especially pyrethroids, for the control of other pests such as bugs. These products very effectively eliminate natural enemies of mites (such as other predatory mites of the genus Phytoseiulus or Amblyseius, anthocorid or staphylinid bugs), but are not as effective against mites themselves. The result is that red spider mite populations, free from their predators, skyrocket explosively.

Therefore, mite control is based, firstly, on prevention and promotion of biological control.

Monitoring: It is essential to periodically check the underside of leaves, if necessary with the help of a field magnifying glass, to detect the first foci. Attacks usually start on leaves closest to the trunk and in the dustiest areas of the plot, such as road edges.

Cultural control:

• Irrigation management: Avoiding water stress is fundamental, as stressed trees are much more sensitive.

• Dust control: On dirt roads, watering periodically to reduce dust can help decrease mite incidence. Dust on leaves hinders the action of natural predators.

• Balanced fertilization: Excess nitrogen favors very tender leaf development appetizing to mites.

Biological control: Conservation of phytoseiid mites (predators) is the most important and sustainable long-term strategy. This is achieved, as we have already mentioned, by avoiding the use of non-selective pesticides. In some cases, in organic farming or covered plantations, inundative releases of these predatory mites, which are marketed for this purpose, can be carried out.

Chemical control: Intervention should only occur when mite populations exceed the tolerance threshold and auxiliary fauna is unable to control them.

• Product choice: It is essential to use specific acaricides. Not all insecticides kill mites. There are very effective active ingredients with different modes of action, such as abamectin (which also controls Psylla), spirodiclofen, etoxazole, or fenpyroximate. It is important to alternate products to avoid the appearance of resistance, something mites are very prone to.

• Sulfur: Dusting or sublimated sulfur is a traditional and effective acaricide, especially with high temperatures (but below 30-32 °C to avoid phytotoxicity). It is a very useful tool in organic production.

• Summer oils: Summer paraffin oils, applied at low concentration, can be effective in controlling incipient populations, as they act by suffocation.

Our philosophy is clear: the best treatment against red spider mite is often not to treat with products that provoke it. Management respectful of auxiliary fauna is the best guarantee to keep mites at bay. If you need a tailored treatment plan that contemplates this philosophy, you can request it through our booking and quote form.

The Flatheaded Root Borer (Capnodis tenebrionis)

The Flatheaded Root Borer is one of the most destructive wood pests for young trees, not only in pistachio but in many other stone fruit trees. The adult is a large beetle (can exceed 2 cm), matte black in color and robust appearance. However, the real enemy is its larva, a legless larva (apodous), whitish in color, characterized by having a very widened prothorax, which gives it the “big-headed” appearance that gives it its common name.

Damage is caused by this larva feeding on the cambium zone and inner bark of roots and tree neck. By excavating galleries in this vital zone, it interrupts sap flow, girdling the tree from the base. Young trees, between 1 and 4 years old, are the most vulnerable. A single flatheaded root borer is capable of killing a young tree.

Symptoms in the aerial part of the tree are progressive and apparently inexplicable decay: the tree stops growing, leaves turn yellowish and small, and finally it withers and dies, often during summer, when water demands are greater and the vascular system cannot respond. If one digs at the base of the trunk of an affected tree, it is easy to find galleries and, with luck or misfortune, the larva. Adults also produce minor damage by feeding on leaf petioles and tender shoots, but this damage is not comparable to that of the larva.

The biological cycle is long, it can last up to two years. Adults emerge in summer and feed. Females deposit eggs in the soil, near the tree neck. When the larva hatches, it buries itself and searches for roots to start feeding. It spends most of its life underground, which makes its control extremely difficult.

Flatheaded Root Borer control is a long-distance race based on prevention and integrated struggle.

Preventive and cultural measures:

1. Rootstock choice: Although there are no totally resistant rootstocks, some like UCB-1, which we promote at Agro Vivero del Mediterráneo for its great vigor, can tolerate attacks better and recover more easily than other less vigorous rootstocks.

2. Physical neck protection: The most effective and widespread measure is to place a protective mesh or tube around the tree neck, from a few centimeters below ground level to about 15-20 cm above. This physical barrier prevents the female from laying eggs in the critical zone. It is important that the mesh is well sealed and leaves no gaps.

3. Tillage: Giving superficial tillage around the trunk during summer can expose eggs to the sun and predators, reducing their viability.

4. Good agronomic management: As with bark beetles, a healthy and vigorous tree will always have more capacity to overcome an initial attack.

Chemical control:

• Soil treatment: At the time of laying (summer), authorized insecticides directed at the tree neck and surrounding soil area can be applied to try to control neonate larvae before they penetrate roots. Active ingredients such as chlorpyrifos (where still authorized) or thiamethoxam applied through drip irrigation have shown some efficacy. It is a complicated strategy with variable effectiveness.

• Struggle against adults: During summer, foliar treatments can be carried out to reduce adult populations, although it is difficult for this to completely prevent egg laying.

Biological control: Entomopathogenic fungi (such as Beauveria bassiana or Metarhizium anisopliae) and entomopathogenic nematodes (Steinernema carpocapsae) are being studied with great interest for soil application. These organisms attack and kill Capnodis larvae naturally. Results are promising, although their use is not yet widespread and requires very specific soil moisture and temperature conditions to be effective.

For new plantations, we insist that physical protection of the tree neck is an almost mandatory measure during the first years. It is a small investment in time and money that can save the lives of many trees and ensure the future of the plantation.

A Holistic Vision: Integrated Pest Management (IPM)

Throughout this tour of the main pistachio pests, we have repeated a concept like a mantra: Integrated Pest Management (IPM). At Agro Vivero del Mediterráneo, we do not conceive plant health in any other way. IPM is not a specific technique, but a work philosophy, a holistic approach that combines all available tools to keep pests below their economic damage threshold, in a way that is sustainable from an economic, ecological, and social point of view.

IPM is based on several fundamental pillars:

1. Prevention: The basis of everything. Includes choosing healthy and adapted plant material (like the pistachio plant we offer), proper soil preparation, choosing a correct planting frame, and all cultural practices that promote a strong and balanced tree.

2. Monitoring and tracking: You cannot control what you do not know. It is essential to regularly monitor the plantation to know what pests are present, at what population level they are, and how they evolve. Using traps, direct observation, and establishing treatment thresholds are key tools.

3. Informed decision making: It is not about treating systematically. Intervention only occurs when strictly necessary, based on monitoring data and knowledge of the pest and crop cycle.

4. Prioritization of non-chemical methods: Before resorting to a pesticide, other avenues must be exhausted. Cultural control (pruning, irrigation, fertilization), physical control (barriers, traps), and, very especially, biological control (promoting auxiliary fauna) are prioritized.

5. Rational use of phytosanitary products: When chemical control is inevitable, it must be done rationally. This implies:

   • Choosing the most selective active ingredient possible, which respects natural enemies to the maximum.

   • Using the correct dose and appropriate and well-calibrated application equipment.

   • Alternating active ingredients with different modes of action to prevent the appearance of resistance.

   • Applying at the optimal time to maximize effectiveness and minimize risks.

   • Scrupulously respecting safety periods.

Implementing an IPM strategy requires knowledge, observation, and often, the advice of specialized technicians. It is an investment in the future of the plantation that translates into greater sustainability, reduced phytosanitary costs, higher quality of the final product, and better profitability in the long term.

At Agro Vivero del Mediterráneo, this is the approach we apply and recommend. Our commitment goes beyond selling a plant; we want your plantation to be a resounding and lasting success. Pest management is a fundamental pillar to achieve this, and we are here to help you build it on solid foundations of knowledge and good practices. Protecting our plantations is protecting our investment and our future. Let’s do it together, with the intelligence that science gives us and the wisdom that nature offers us.