Fruit Properties of Walnuts

Walnut (Juglans regia L.), in botany, is in the Dicotyledoneae class Juglandales order, Juglandaceae family and Juglans genus. Among the 18 types of Juglans, whose characteristics are determined today, the first thing that comes to mind when it comes to walnut with its superior fruit quality is J. regia, also known as “Anatolian walnut”, “Iran walnut” and “English walnut”.

Wild types of walnuts have spread in many parts of the world. However, the homeland of walnut is the Ghilan region of Iran according to some, and China for others. On the other hand, a larger majority show a much larger area as the homeland of walnut. According to its proponents, the Carpathian mountains walnut group of Turkey, Iraq, Iran, Afghanistan, South Russia, India, Manchuria and Korea is a vast region extending from the natural plants.

The Anatolian walnut (Juglans regia L.), which has a large natural spreading area in the world due to its origin, has been taken out of its natural spreading area by various migrations and trade caravans, and today it is a fruit species that is grown almost everywhere in the world except tropical regions. Until recently, walnut cultivation comes as Turkey has said, that Greece, Italy, countries such as France was to follow, however walnut production in the 1867 walnut began the US, all these countries have become the most important country in the walnut leaving and foreign sales behind.

Anatolia, whose fruit growing culture goes back to ancient times, has been among the homeland regions of walnuts, as is the case with many types of fruit. As a result of the cultivation made until today, Anatolia has a walnut tree number exceeding 4.5 million.

This rich resource has two main advantages in our country, which has precious walnut types in every region. First, the walnut production of approximately 120 thousand tons, obtained with more than 5 million trees, has placed our country in third place in the world ranking. However, it is also a negative situation that only 1-2% of this produced amount goes to foreign sales and therefore our country is in the last place in the world walnut export ranking. The only reason for this situation is that our production is made with trees grown entirely from seed, not standard varieties, and no cultural practices are made.

The fact that each tree that grows from a seed has different characteristics, therefore, the inability to supply the appropriate amount of products to the standards emerges as the most important reason that makes our export difficult. The second advantage of the existing walnut existence in Anatolia is that it is a rich source for breeding studies since it has a wide genetic variation. This variation allows the breeding studies to be successful in a shorter time with appropriate methods.


Walnut is a very important fruit type in terms of health and nutrition. Generally, walnuts contain 3.5% water, 15-30% protein, 55-77% fat, 1.5-3% ash, and 5-15% carbohydrate (weight cellulose). In addition, the fruit of walnut is rich in minerals such as Ca, P, Mg, Fe, Na, K as well as vitamins A, B1, B2, B6, C. 1 kg of walnuts provides approximately 7,000 calories of energy.

Walnuts are consumed in many different ways. It is consumed as a snack, in the cake and biscuit industry, in the perfume industry, in the production of jam, halva, in the paint, tannin, plastic and rubber industry, as an oil, in the pharmaceutical industry, in the production of sausage, samsa, and fruit pulp. In addition, walnut is one of the most sought-after materials in carving because of its extremely precious timber.

In recent studies in many countries, especially in the USA, walnuts are especially recommended for patients with some heart diseases. The fact that walnuts are good for people with some health problems in terms of heart and cholesterol has increased the importance of walnuts in recent years.


3.1. Tree Structure and Root:
· Walnuts grow fast and grow up to 25-40 m and a tree can cover an area of ​​300-500 m2.
· Walnut trees generally have a “flat” crown shape. Crown shape is also seen in “semi-upright and upright” structure.
· Walnuts are pile rooted and capillary roots can be found abundantly. Roots can grow up to 3-5 m deep.

3.2. Gövde ve Dallar
· Gövdede dallanma genelde toprak yüzeyinden 1-2 m yükseklikten başlar.
· Gövde çevresi 5- 6 m ye kadar gelişebilir.
· Gençlik yıllarında düzgün yüzeyli ve gümüşi renkte olan gövdede çok ileri yaşlarda renk koyulaşır (gri-siyah) ve kabukta uzunluğuna çatlaklar oluşur.
· Sürgünler, tüysüz, parlak zeytin yeşili veya esmer renktedir.

3.3.Leaves and Eyes
· Leaf; It consists of 5-13 leaflets arranged opposite each other on a long stalk.
Leaflets are in the form of broad ellipses and have full edges. Their tips are pointed and their length varies between 6-12 cm. The color is bright green and they are arranged spirally on the body.
The eyes are on the branch tips and leaf axils (1-3) and are dark brown in color. Three eyes are large. The larger one of the eyes in the leaf axils picks up and creates the wood branch.
· There are female flowers at the tips of the shoots that are formed only from the tip buds of the unproductive varieties. However, female flowers occur in almost all buds (including leaf buds) of fertile varieties.

3.4. Flower Structure and Fertilization Biology
Flowers in walnuts are monoic in nature. In other words, male and female flowers are on the same tree but in different places. Pollination in walnuts occurs with the help of wind

3.4.1. Male Flowers
  Male flowers are formed on green colored and drooping tassels (kitty) 5- 20 cm in length, which are formed by the development of side buds on the shoots of the previous development period in spring (Figure 1). A mature walnut tree can produce 5000-6000 tassels. In addition, a tree’s capacity to produce pollen (pollen) can range from about 10 to 100 billion.
3.4.2. Female flowers
The number of female flowers occurring at the tips of the shoots during the spring development period may vary between 1 and 26 (Figure 2). In the female flower, 4 perianth leaves and brachicles are fused with the ovary. The number of sepals is between 3-6 and there is no petal. The stigma is indented, with a seed outline in the ovary. While the outer wall of the ovary forms the green shell outside the fruit, the hard shell is formed by the hardening of the inner walls of the ovary. It is a seed consisting of walnut, embryo and seed shell. The eaten part is directly itself.

4.1. Climate
Walnuts are cold enough to meet the need for cooling in winter and spring; In the spring and summer months, they want warm enough (25- 350C) to ensure normal growth and maturation. Summer temperatures higher than 400C may cause burns in the walnut green shell and shrinkage in the walnut. Although the walnut plant is generally damaged in temperatures below -200C, there are varieties that can withstand -400C. In addition, temperatures below –10C during the bud period, –30C during the full blooming period and –10C during the small green fruit period can be harmful. Factors such as the degree of low temperature, the falling speed, and the duration of the cold play an important role. The cooling requirement of walnut varieties varies between 500-2000 hours under + 7.20C. For a regular product, the chilling requirement of walnuts must be met.

In terms of walnut cultivation, a total annual precipitation of at least 500 mm is sufficient, but it is important that this precipitation is regular. In order for the fruits to develop normally, there should be sufficient water in the soil in summer. In addition, rains and excessive winds during the flowering period may cause a negative situation, especially in terms of pollination-fertilization.

4.2. Toprak
Walnut has a strong root system that can go down to a depth of 2-4 m. Therefore, problems may arise in terms of aquaculture in places where soil depth is low. In order to avoid problems in terms of cultivation, the depth of the soil should be at least 2 m and the soil should be permeable.
Soil pH should be around 6-7 and there should be no alkalinity and salt problems in the soil.
The soil should be well-drained, permeable, rich in organic matter and airy. The high water holding capacity of the soil is important for walnut cultivation. However, walnut is not a very selective fruit type in terms of soil.

  1. REPRODUCTION OF WALNUT 5.1. Generative (by Seed) Propagation The
    offspring plants that occur in the propagation by seed do not possess almost any characteristics of the parent plant. For this reason, reproduction by seed in walnuts is not a preferred propagation method except for obtaining rootstock or seedlings and breeding studies, due to genetic expansion.

5.1.1. Properties
to be Searched in Seeds Walnuts to be used as seeds;

* It should
be full * Its development should be complete
* It should be taken from healthy and well-developed trees
* Fruits damaged for any reason should not be used as seed.

5.1.2. Folding
Seeds Storing in humidified environments in order to meet the cooling needs of the seeds, to remove the obstructing factors, to soften the seed coat, to increase the germination power of the embryo by facilitating the water and oxygen intake and to accelerate it is called folding. The general advantage of folding seeds is that early and regular germination is achieved by eliminating the effects of factors that inhibit seed germination.
The start of folding is determined according to the state of the soil in the place where the cultivation will take place.
Crates (such as fruit and vegetable crates) that can be easily carried by a person can be used in folding. After placing the gravel large enough to cover the holes on the bottom of these crates, folding sand (construction sand) is laid on it properly. Seeds are planted one by one on this sand. Then the seeds are covered with sand, and then one row of seeds and one row of sand continue until the casing is full. After the folding process is completed, the thickness of the sand to be put on top should be slightly more than the others. After the container is filled, the sand is moistened with strainer buckets. Later, these folding cases are taken to environments such as cool basements, ordinary warehouses, etc. whose temperature varies between 0 and 80C.
The folding time of the seeds in walnuts varies between 60 and 90 days, depending on the variety. When the hard shell of the seed cracks and the root tip appears, folding is stopped. Seeds are sown in the soil to a depth twice their size. In order for seedlings to develop well after seed planting, care should be taken to irrigate the seedlings, especially weed removal.
Cutting the pile roots during the resting period, a while before the removal of the decays, improves the fringe root formation and increases the retention success in staggering.

5.2. Vegetative Propagation
Walnuts, which cannot be reproduced by seed due to genetic expansion, are propagated vegetatively. Although it is difficult to vaccinate in walnuts, the vegetative propagation method that maintains its validity today is propagation by grafting.
5.2.1. Reproduction by Vaccine Factors Affecting Vaccine Success

Temperature: The ambient temperature being between 23-300C increases the success of vaccination in walnuts.
Humidity: Humidity of the environment positively affects the success of vaccination.
The experience of the vaccinator: Since the success of vaccination in walnuts is generally lower than other fruit types, the experience and skill of the vaccinee is very important in vaccination success.
Materials used in the vaccine: The materials used must be of good quality. For example, the blade surface should be very smooth and very sharp to cut in one stroke. Preferably, cotton thread or grafting tape should be used to wrap the vaccine.
Pen: Healthy and well developed annual shoots are taken as cuttings. The untreated eyes (preferably between the 2nd and 5th eyes) on the pen are used in the vaccine. Cut pens must be kept in a humid environment during storage and vaccination.
Vaccination time: One of the most important factors that increase the success in vaccination is the time of vaccination, and it is the most appropriate time when both the seedlings and the shoots to be taken from the shoots leave their shell easily. The following method can be applied to determine the most appropriate time of vaccination; When the shell on the vaccination slide is removed, if the growth point remaining under the eye remains in the shell, it is time for this eye to be vaccinated. However, if the growth point remains in the exile, that is, in the wood tissue, it means that the vaccination time has passed for this eye. In this case, a gap occurs under the eye in the shell. When the vaccine is administered, the air in this space under the shell causes the vaccine eye and its surroundings to turn black and dry. Such eyes are not preferred for vaccination. Another of the most important practical criteria determining the initiation of eye vaccinations in a region is when the crops start to be harvested in that region. In other words, when the crops start to be harvested in a region, it means when eye vaccinations can be made in walnuts for that region. Most Commonly Used Vaccines for Growing Walnuts:
Eye Vaccines;

* T-Eye Vaccine
* Patch Eye Vaccine
* Shell Patch (Thimble) Eye Vaccine
* Flake Eye Vaccine
* Green wood Eye Vaccine

The most used and most successful eye vaccines in walnuts are “T eye” vaccine (Figure 15) and “Patch eye” vaccine.
Pen Vaccines;

* Side Vaccine
* Splitting Vaccine *
* Inlay Vaccine
* Shell Vaccine (Figure 16)
* Tongue Vaccine * (It is administered in mid-February or in the beginning of March. Figure 17)
* Mute Vaccine
* Strip Vaccine
* Shepherd Vaccine
* Wedge Vaccine

* The most used and successful “diluted vaccine” in walnuts and “splitting vaccine” are the most used as the variety replacement vaccine.

5.3. Walnut Rootstocks

The following types can be used as rootstock for walnuts.

  1. J. hindsii
    2. Paradox (J. hindsii X J. regia)
    3. J. regia
    4. Royal (J. nigra X J. hindsii)
    5. J. Major

Although different rootstocks are used in walnuts, the most used and preferred rootstock is the rootstock of Anatolian walnut (J. regia L.).

6.1. Setting Up a Garden In
walnut, which lives very long and is difficult to reproduce by vaccination, it is necessary to know the ecological characteristics of the region well before setting up a garden. Walnuts should not be grown in regions where winters are very extreme and constantly low temperatures prevail, and in places with extremely hot summers.
Since walnuts have a strong root system that goes deep, the soil depth should be at least 2- 2.5 m and there should be no impermeable layers. There should not be too much alkalinity and salinity problems in the soil of the area where the breeding will be done.

: It is common for male and female flowers to mature at different times in walnuts (dichogamy). In this case, there are homogamous types and varieties with male and female flowers maturing at the same time, as well as varieties whose male flowers first mature (protandry) and female flowers mature before (protogyny). Therefore, when establishing a walnut garden, either a variety of male and female flowers maturing at the same time (homogamy) or a mixed planting with more than one variety whose male and female flowers mature at the same time should be preferred.

6.3. Planting Although
planting intervals vary according to ecological and maintenance conditions, the most ideal planting intervals in walnuts; It is 12 x 12 m, 10 x 10 m, 10 x 8 m or 8 x 8 m.

Planting of the seedlings begins in the resting period (from the foliage) and continues until the eyes wake up. The seedlings should be disassembled very carefully and care should be taken not to damage the roots. During planting, especially root pruning should be done on seedlings. Planting pits should be opened at least 60-70 cm wide and 80-100 cm deep. Saplings should be planted so that the grafting points remain above the ground and the pits should be filled with top soil in the garden. Life water should be given to the seedlings immediately after planting. After planting, considering the future timber situation, the sapling trunks should be cut approximately 1 – 1.5 m above the soil surface and crowning pruning should be done. After that, the saplings should be tied to the props considering the prevailing winds in the region.

6.4. Tillage In
spring, when the soil pans, a deep plowing is done. Tillage in this period is very important in terms of ventilation of the soil as well as providing weed control. Tillage can be done in terms of weed control in the summer months. The version to be plowed in autumn is important in terms of penetrating and keeping rain and snow water in the soil. While cultivating the soil, care should be taken not to injure the roots.

6.5. Irrigation
Walnut trees have a wide leaf surface because they are large and widely branched. For this reason, it is very important to provide enough water to walnuts with high water loss due to perspiration.

For walnuts, it is very important to meet the water requirement during the spring development, fruit growth and filling periods. The lack of water during these periods will slow the growth and development and cause the fruits to not fill enough, so quality and yield decreases.
One of the most important points to be considered in irrigation is to ensure that the water reaches the effective root level. In the first years of walnuts, it is necessary to irrigate twice a week, taking into account the condition of the region and the water source. As the irrigation method, one of the furrow irrigation, release, drip and bottom sprinkler irrigation systems can be preferred. Any water that is not contaminated with harmful factors such as chemical wastes can be used for irrigating walnuts.

6.6. Fertilization
Walnut is not a very sensitive plant in terms of fertilization if there is no extreme problem in the soil. However, due to its nature, the most important plant nutrient requirement may be nitrogen. According to the results of the soil analysis to be made, the nutrients missing in the soil should be given to the soil within a certain program.

6.7. Pruning
Walnut trees form a large and large crown. However, these trees generally do not require too much pruning. In addition, it is beneficial to remove the dried and intertwined branches and to prune the spacers to allow light to easily enter the tree crown. Although the peak branch pruning system is generally applied as shape pruning in walnuts, the type and amount of pruning may also vary depending on the environment and the purpose of growing the trees.


Harvesting of walnuts is considered to be the period when the walnut and green shell ripen. The period when the thick opens and leaves the hard shell is the ripening signs of the green shell. If the walnut is a sign of maturity; This is the period when the package texture between the walnut and the hard shell begins to turn brown. Often the green shell ripens later than the walnut. Harvesting at the time of maturity of the walnut will increase the commercial value of the walnut due to the light color of the walnut in this period. However, very important quality losses may occur if the grower waits for the harvest time of the green bark to mature.

Climate can have a significant effect on the harvest time of walnuts. In areas with a cool climate, the ripening time of the walnut and the ripening time of the green shell usually coincide with the same period. High humidity speeds up the opening of the green peel.

An important factor affecting the harvest time is the cultivated variety. For example, varieties such as Chadler and Serr have a light internal color when harvested on time and correctly.

Collecting the harvested fruits, separating the green peel and drying the fruits, etc. should be as quickly as possible to avoid quality losses.

In the fruits that are under the sun, the fruits that remain on the green peel for a long time are damaged.

7.2. Harvesting Methods: Harvesting of
walnuts is done by two methods, manually and mechanically. While the beating Turkey in walnut-shaped pole tree harvesting is done mechanically roads in the leading countries. During the harvest made in the form of beating trees, significant damages can occur, especially on the branches that will yield in the next year.

Mechanical harvesting; It is made by shaking the main branches of the tree or the tree trunk with various shakers and making the fruits fall from the tree to the ground. For this purpose, different shakers (Cable shakers-Eccentric shakers, Poner moving shakers, Pneumatic shakers etc.) are used.

7.3. Post-Harvest: In
order to minimize quality losses after harvest, the green shell should be easily separated from the hard shell, that is, the fruits should be fried immediately. In some regions, covering the green shell with nylon, thick cloth and sacks in order to soften and remove it easily can cause significant quality losses. In some countries, roasting is done completely mechanically.

It is asked to come out as a whole for market value. If the harvested fruits are to be marketed internally, the walnuts are broken down before they dry (when they are moist). Thus, it is provided to come out in an easier way.

In our country, walnut crushing operations are generally carried out by women in places called exhibition halls by hitting them with a hammer. After the crushing process, walnuts are classified according to their color and subjected to packaging.

7.4. Drying:
Fruits that will not be considered as walnuts, that is to be marketed as shelled, should be dried immediately after roasting. The drying process is very important for the storage life of walnuts. For this, the highest humidity levels that should be found in shelled and kernel walnuts are determined by standards. For example, dried according to TSE; A moisture content of 8% is required for shelled walnuts and 5% for kernels.

In our country, walnuts are generally dried outside in the shade. In some regions, drying is done by keeping it under the sun for 7-10 days. This causes various quality losses such as darkening of the interior color. Therefore, this drying method is wrong. If there is no other drying option, at least drying should be done outside in shadow areas. In other words, fruits should not be dried under direct sunlight. However, in the countries that have a say in the world walnut production, drying is done completely by mechanical means. In mechanical drying processes, fruits are generally kept at 30- 350C for 24 hours. The temperature rise above 400 C is undesirable in terms of internal quality.

7.5. Storage and Packaging: Since
walnuts are fruits with high fat content, storing them under appropriate conditions is important in terms of fat deterioration in the inner fruit. Therefore, walnuts can be stored at low temperatures (0-40C) and in dry environments for a long time.

Packaging is a very important stage in the marketing of a product. For this reason, packaging with healthy materials appeals to consumers in terms of marketing both shelled and walnut. There is a clear difference between the appeal of mixed walnuts filled with large sacks and walnuts, all of the same color, packed in small weight. For example, it is very important for consumers to make and label the walnuts with vacuum-proof plastic bags that are not transparent to light.

The correct operation of the harvest and the post-harvest period is one of the issues that need to be paid attention to for the producer and therefore the walnut business in the country.

MODERN HARVEST AND AFTER (major stages) in countries that have a say in walnut cultivation

  1. It is also known as oak root rot or fungal root rot. It is caused by a soil-borne fungus called Armillaria mellea. Fungus infects the roots of walnut trees, root neck and lower parts of the trunk. The first symptoms are small chlorotic leaves, young foliage, and back death at shoot tips. Generally, symptoms towards the root system or root collar where the fungus is infected are observed. As a result, the fungus destroys the entire root system of the tree or causes tree deaths by wrapping around the lower trunk like a belt.DISEASES AND PESTS

    8.1. Diseases
    8.1.1. Armillaria Root Rot

Struggle: Before establishing walnut orchards in Armillaria-infected soils, protective measures should be taken and rootstocks resistant to fungus infection should be used. Although it is an expensive and difficult application before planting, soil fumigation with methyl bromide will greatly reduce tree deaths. Diseased trees should be removed and removed from the field together with all plant residues. The possibility of carrying infection should not be ignored for trees that are close to diseased trees and do not show symptoms.

Figure 1. The condition of Armillaria root rot in the body.

8.1.2. Root Throat Tumor
Bacteria (Agrobacterium tumefaciens) disease. The pathogen enters the plant tissue through wounds and forms a tumor around the root collar. Tumor formations are also observed in the roots over time. The central parts of the tumors die and cause fungi and other pathogens to settle in the cavities formed at this point, causing the wood tissue to rot. The height of infected young trees is short, wood rot is observed in old trees.
Struggle: The best method of combating root collar tumors is to obtain saplings from nurseries with healthy breeders, transport them, plant them in the field and avoid injuries throughout their entire breeding life.
Biological control is possible with the pathogen. Before planting, successful results were obtained by dipping the seedlings into suspensions prepared with Agrobacterium radiobacter strain K84.


Figure 3.Damages caused by walnut blight

8.1.3. Walnut Blight
Bacteria (Xanthomonas campestris pv. Juglandis) disease. The pathogen infects only plant species belonging to the Juglans genus. They spend the winter in sleepy eyes, spread by rainwater and sprinkler irrigation and infect. Trees are susceptible to bacterial infection during the whole growing season. Young shoots can be infected by the agent during the period when they are actively green and watery. The bacteria attacks all the tissues of the leaf (parenchyma, middle vein, side veins, veinlets and petiole). It forms brown-black spots of several millimeters on the parenchyma. Numerous spots and line-shaped formations completely cover the leaf surface, causing leaf deformities and deformations. Fruits are also very sensitive at the beginning of their formation and during flowering periods. Small, black, watery lesions are observed on the surface.
Struggle: The fight against the disease factor is very difficult as it spends the winter in sleepy eyes. Preventive pesticides are applied with copper preparations in the first formation stages of walnuts. In walnut orchards where severe infections were seen before, applications should be made at regular intervals, taking into account the wet days in winter.

8.1.4. Walnut Anthracnose Disease (Gnomonia leptostyla)

Symptoms of the disease are seen in leaflets, fruits, young shoots and petioles of walnut trees. The disease is especially seen in places where relative humidity is high and at every altitude. Although it is mostly a leaf disease, the disease that passes from the green fruit shell to the fruit also causes damage to the fruits. The disease infects young leaves after the leaflets exceed half their size and causes discoloration around the penetration point. Later, these parts turn brown. With the effect of the disease, early defoliation starts in the middle of summer, when it is intense, all leaves may fall. The disease spreads rapidly and its symptoms increase suddenly, especially due to the rains in June-July and the dew formed by the day-night temperature difference in this period.
Struggle: Leaves fallen on the ground, which are the source of infection, should be collected and burned in autumn or buried in the ground. During pruning, contaminated branches should be removed from the garden. In the gardens with disease, first spraying when the buds start to burst and the leaves are newly formed; Second spraying when leaflets take half the size; The third application should be done when the fruits take the size of the hazelnut.

Figure 4. Walnut anthracnose disease

8.2. Pests

8.2.1. Apple Worm (Cydia pomonella L.)

It is a juvenile butterfly, the butterflies are gray in color and average 10 mm in length. A triangular dark spot on both wing tips of butterflies is characteristic. The caterpillars are 1 mm long when they first hatch, mature larvae that have completed their development are 15-20 mm long and whitish pink in color.
Apple worm spends the winter in mature larvae between cracked shells in tree trunks. Adult emergence in the spring is seen at the end of April and the beginning of May depending on the environmental conditions and spreads over a period of approximately one month. In order for the hatched adults to lay eggs, the evening twilight temperature should be above 15 ° C for two days in a row. Eggs are laid on the leaves and fruits one by one. The caterpillars hatched enter the fruit within 4-8 hours and are fed in the fruit. The larval period lasts 30-40 days and the pest gives 2-3 offspring per year.
Apple worm is one of the most important pests of walnuts. The damage is directly to the fruit and the caterpillars that enter the fruit destroy the walnut kernels and cause a decrease in quality and yield due to early casting.
Struggle: As a cultural precaution, wormy fruits that have fallen on the ground should be collected and buried deeply in the ground, the thick branches and trunks of the walnut trees should be wrapped in corrugated cardboard trap tapes at the beginning of June and the larvae coming to them should be destroyed during the controls. Resistant varieties should be preferred in new gardens. Although the pest has a low threshold of control due to its direct damage to the fruit, it has effective natural enemies, but generally a pesticide control is required. In the pesticide control, it is important to determine the pesticide time. The larvae that hatch from the eggs must be brought before they enter the fruit. In determining the struggle time, the first adult exits of the pest are monitored, for this purpose, sexual attractive traps and effective temperature totals are used.



8.2.2. Walnut Green Bark Fly (Rhagoletis completa)

Walnut Green Shell Fly adult is yellowish brown. It spends the winter as a pupa in the soil and its adult flights begin at the beginning of July and continue until the beginning of September. They lay their eggs in groups and the eggs hatch in an average of five days. The hatched larvae feed on the green shell and damage the shell tissue. Larval period lasts 3-5 weeks depending on environmental conditions. In the later stages, they spoil the appearance of the hard shell as well as damage the fruit. The pest gives offspring once a year.

Figure 6a. Green bark fly Figure 6b. Green shell eggs adolescent of the fly

8.2.3. Aphids (Choromaphis juglandicola, Callaphis juglandis)

Adult individuals are yellow in color and 1.5-2.0 mm in length. The life cycle of both aphid species, which are harmful in walnuts, are similar and adult individuals with and without wings can be found in the population. They spend the winter as eggs, and all of the individuals that hatch in the spring are female, and they reproduce throughout the summer by giving birth to live offspring without fertilization. Depending on factors such as daily lighting time, temperature and nutritional status, individuals are formed to lay eggs in autumn and winter eggs are laid. Depending on the environmental conditions, they give a large number of offspring in a year.
Aphids that feed on plant sap in leaves slow down the development of walnut trees and negatively affect the quality and yield. If the aphid density increases in the spring, there is a decrease in the fruit size, while the high aphid density in the summer causes the fruit core to wrinkle. At the same time, they cause fumajin formation due to the sweetish substance they secrete.
Struggle: Aphid species have many natural enemies and these can generally suppress the pest. The density of beneficial species should be taken into account when deciding on pest control.

Figure 7.Pest aphids on walnuts

8.2.4. European Red Spider (Panonychus ulmi)

The adult females of the European red spider are dark red in average, 0.8 mm in length, their eggs are brick red in color, in the form of an onion and have a stalk on it. It spends the winter in the branches and branches of the trees during the egg period. The larvae hatched in the spring, pass on to fresh shoots and begin to feed by sucking the sap of the leaves. After they reach maturity, they lay their eggs on the lower surfaces of the leaves. They do not form a web in the feeding places. The number of offspring in a year reaches 8-9.
Challenge: Before deciding on a medicated fight against the European red spider, the intensity of its natural enemies must be taken into account. In the pesticide control, when the density exceeds 3 to 5 individuals per leaflet, it should be applied with an appropriate acaricide.

8.2.6. Crust lupine and cochnials8.2.5. Two-Point Red Spider (Tetranychus urticae)
The color of the two-point red spider adults is greenish or brownish green. Its eggs are light yellow, transparent and round. During the adult female period, they spend the winter under the bark of trees on the trunks of the trees, among the fallen leaves and in the spring they leave their winter quarters. It feeds by sucking the sap on the lower surface of the leaves and causes the tree to weaken. It knits a dense web at the feeding place. Depending on environmental conditions, it can give 10-15 offspring per year.
Struggle: Unnecessary drug applications should be avoided against other pests. When its density exceeds 3 to 5 individuals per leaflet, application with a suitable acaricide may be required.

Harmful in walnuts are scabbite and scabbite species, San jose crust lupine (Quadraspidiotus perniciosus) and Brown cochineal (Parthenolecanium corni).
The shells of the adult females of the San Jose crustacean are brown colored and 1.7-2.0 mm in diameter. When a longitudinal section is taken from the bark of the branch where the pest is found, blood-red emgi stains appear. It spends the winter as first period larvae and gives three offspring a year. Harmful by sucking plant sap in tree trunk, branch, leaflet, shoot, buds and fruits. It releases toxic substances during emgi and causes the tree to weaken. In its struggle, the branches contaminated with the pest during pruning should be cut and removed from the garden, and clean saplings should be used while the garden is established. In case of necessity, winter control can be done against the pest, and spraying can be done in the early spring and summer months in the larval period.
The shell diameter of adult brown cochineal females is up to 3.5 mm and brown in color. It spends the winter in the young branches and shoots of the trees as second period larvae. It is harmful by sucking the sap of the harmful leaflets, branches and shoots that give offspring once a year. At the same time, it causes fumajin formation due to the sweetish substance it secretes. Due to the fact that it absorbs the sap of the plant and forms fumajin, the shoots and branches of the trees cannot develop, the leaves fall off, weakening the tree and adversely affects the yield. In the struggle, the branches contaminated with cone should be removed from the garden during pruning. In densely populated gardens, medication should be applied against larvae when more than half of the eggs are opened.


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