Almond treatments, most common diseases and pests of this fruit tree

almond amygdalus communis

almond amygdalus communis

The almond (Amygdalus communis) is an important crop, highly appreciated for the seeds of its fruits. the almond originated from Asia and it has been planted since Greek and Roman time. Nowadays, the largest almond producer is USA.

Main diseases

Virus diseases

Plum pox virus

This virus disease affects most of the stone fruit trees. Discolored, circular stains are visible on all leaves. The symptoms will disappear during the hot summer months. The affected fruits will fall off the trees before maturing. If the attack is severe, the circular spots can even be seen of the seeds. This virus is spread through the planting material, cicadas, aphids and pollen.

almond amygdalus communis - plum pox virus

Prevention and control measures:

  • Planting healthy trees
  • Spatially isolating the stone fruit orchards
  • Destroying the pest plants and shrubs near the orchard
  • Applying insecticides to control the insect population

Bacteriosis

Bacterial canker of stone fruits, caused by Pseudomonas syringae pv morsprunorum

This disease spreads to young sprouts, their leaves and fruits. Small, circular spots that have a watery aspect will appear on the leaves. When the humidity is high, the bacterial exudate appears on the surface of the stains and this is visible as a cloggy pellicle of a white-yellow color. On drier days, the affected tissues become dry and fall off the leaves. This will make the leaves have a pierced aspect. A severe attack will lead to tree defoliation. The fruits have small, brown-reddish stains. This attack on the fruits will cause their deformation and crack. This is how the almonds can lose their commercial values. The sprouts will have long stains and a brown and destroyed bark. On all of the above-mentioned wounds, a viscous fluid, that is specific to all bacterial diseases, will be observed. The wounds grow larger from one year to another and evolve into open cankers. The bacteria will find its way into the tree using the stomates and most of the infections are produced during grafting.

almond amygdalus communis - bacterial canker of stone fruits

Prevention and control measures:

  • Using healthy grafts rootstocks
  • Chemical treatments during the bud opening phase, using Zeama Bordeleza, Melody Compact 49 WG, Funguran OH 50 WP, Champ 77 WG.

Crown gall disease, caused by Agrobacterium radiobacter pv. Tumefacias

Small and soft tumors develop on the roots and stems and these lignify as the disease evolves. The tumors have different shapes and sizes. These tumors generate formations similar to leaves, sprouts and buds. The cells that form these tumors are large and deformed. This bacterium gets into the tree through the wounds inflicted to the plants by nematodes, hail, etc. The emergence of this disease is favored by temperatures ranging from 22 to 30 degrees Celsius and an atmospheric humidity of 80%.

almond amygdalus communis - crown gall disease

Prevention and control measures:

  • Sorting the seedlings before planting
  • The orchard needs to be started on parcels that have been well prepared in advance
  • Disinfecting the scissors and other tools used for tree maintenance
  • Cutting the affected branches off until the healthy areas are reached and applying a treatment using 4-5% Zeama Bordeleza and covering the wounds using cicatrizing mastic
  • Bathing the roots of the seedlings in 1%     Zeama Bordeleza or 0.025% Topas 100 EC
  • Copper-based treatments to be applied during the vegetation phase

Mycosis

Brown rot of stone fruits, caused by Monilinia laxa

This disease affects all aerial plant organs, causing significant damage during cold and rainy years. The affected leaves hang without falling off, the flowers turn brown and wilt and the branches bend as a hook. The young leaves wrinkle, turn brown and massively fall off. The pulp of the mature fruits rots and on their exterior grey-yellow stains appear. Finally, the fruits mummify and remain on the tree, assuring the disease’s spread to the following year. The fungus winters on the mummified fruits and inside the bark of the affected branches.

almond amygdalus communis - brown rot of stone fruits

Prevention and control measures:

  • Gathering and destroying the affected fruits
  • Cutting off and burning the affected branches
  • Cutting the affected branches up to the healthy areas, applying treatments using 4-5% Zeama Bordeleza and covering the wounds with cicatrizing mastic
  • Chemical treatments to be applied during the vegetative rest period, using copper-based products (Alcupral, for example) and during the vegetation period using Switch, Score, Topsin;

Shot hole disease in stone fruits, caused by Stigmina carpophylla

This disease is very common in unattended orchards and it causes significant damage to stone fruit trees. Circular stains appear on the leaves, where the tissues turn brown and eventually detach from the leaves. Dot like formations can be observed on the fruits and these are surrounded by a red-violet colored margin. The pulp of the fruits loses its taste and texture. The fungus also affects the sprouts, where it grows brown formations, followed by wounds that leak a resin substance. This attack method is very dangerous as it wilts the sprouts which carry the fruit-buds. The fungus is spread thanks to its spores and it can live during the winter season in the resin that leaked out of the wounds. The fungus can also winter as mycelium on the surface of the branches.

almond amygdalus communis - shot hole disease in stone fruits

Prevention and control measures:

  • Cutting off and burning the affected branches
  • The wounds resulted after the cuts will have to be covered using mastic
  • After performing the cuts, the trees will have to be treated using 4-5% Zeama Bordeleza
  • Treatments to be applied during the vegetation period, using Score 250 EC, Folpan WDG, Captan;

Powdery mildew, caused by Sphaerotheca pannosa var. persicae

The attack can be first seen on the leaves of young sprouts, as white stains. These extend and cover the entire surface of the leaves. As the disease evolves, by mycelium becomes grey and dusty. The affected tissues become wrinkled and wilt. The fungus also attacks young fruits. these are covered by a white, mycelian felt. The fruits crack and rot.

almond-amygdalus-communis-powdery-mildew

Prevention and control measures:

  • Balanced fertilizing
  • Planting resilient species
  • Burning the affected sprouts and fruits
  • Chemical treatments during vegetation, using Systhane Plus 24 E, Thiovit Jet 80 WG, Kumulus DF, Topas 100 EC, Karathane M 35 CE;

Leaf curl, caused by Taphrina deformans

This disease mainly affects the leaves, but during favorable years it can also affect the fruits and sprouts. Young leaves have bumps on their superior sides, or are deformed, or are larger in dimensions than healthy leaves. The affected leaves have a red color and as the disease evolves this color progresses into yellow. When the tree has been severely affected the leaves fall off. The affected branches and sprouts have slowed growing rhythms and are sensitive to the winter time frosts. The attack on the leaves is rare and it is recognizable as small, white stains, next to which the tissues will rot.

almond amygdalus communis - leaf curl

Prevention and control measures:

  • Chemical treatments, using: Dithane M-45, Bravo, Score, Captan, Systhane Plus 24 E;

Main pests

Codling moth (Cydia pomonella)

This is a polyphagous species that attacks many trees. Larvae of different ages attack the fruits. The females lay the eggs directly on the fruits, or on the leaves surrounding the fruits. After hatching, the larvae dig galleries inside the affected fruits, leaving their excrements inside. This is why the fruits can no longer be consumed.

almond amygdalus communis - codling moth

Prevention and control measures:

  • Using pheromone traps to detect the adults’ flying paths
  • Chemical treatments using Reldan 22 EC, Novadim progress, Laser 240 SC, Affirm, Calypso 480 SC;

Brown-tail moth (Euproctis Chrysorrhoea)

This is a polyphagous species that attacks a series of trees and fruit-bearing trees. It grows one generation per year and it winters as a larva inside a cocoon inside the tips of the sprouts. The larvae attack the buds and the leaves and it can lead to tree defoliation. The presence of this pest is barely detectable. This is why the trees need to be thoroughly visually inspected.

almond amygdalus communis - brown tail moth

Prevention and control measures:

  • Taking out the branches where the larvae are present
  • Chemical treatments using Karate Zeon, Faster, Laser 240 SC, Calypso 480 SC, Affirm;

Fall webworm moth (Hyphantria cunea)

This is a polyphagous species which affects ornamental trees and fruit-bearing trees. It gorws 2 generations per year and it winters as a pupa inside the soil’s superficial layer. This insect causes tree defoliation and implicitly, a fruit production decrease. The caterpillars stay on the inferior sides of the leaves and eat them. They begin weaving some sort of a nest inside which they feed.

almond amygdalus communis - fall webworm moth

Prevention and control measures:

  • Chemical treatments, using   Faster 10 CE, Kaiso Sorbie, Affirm, Novadim Progress, Laser 240 SC;

Peach twig borer (Anarsia lineatella)

It grows 3 generations per year and it winters as a larva underneath the exfoliated tree barks. During spring, the larvae leave the winter-time shelter and attack the buds. The larvae chew penetration holes inside young sprouts. Newly emerged females lay their eggs on the sprouts and the larvae will go into the fruits of the early emerging species. The larvae of the following generations, will get into the fruits that are still ripening, where they dig deep galleries.

almond amygdalus communis - peach tree borer

Prevention and control measures:

  • Cutting off and destroying the affected branches and sprouts
  • Chemical treatments using Coragen, Karate Zeon 50 CS, Bactospeine DF, Calypso, Laser 240 SC;

Acari

These insects are barely visible for the naked eye. They are polyphagous species that attack a lot of plants and fruit-bearing trees, both cultivated or spontaneous species. These feed on the plants’ cellular juice. After the attack, the leaves have a parchment-like aspect, the flowers abort and the tree’s growth will be stagnated.

almond amygdalus communis - acari

Prevention and control measures:

  • Chemical treatments using Voliam Targo, Nissorun 10 WP, Sanmite 10 SC, Milbeknock, Vertimec 1.8 EC;

Oriental fruit moth (Cydia molesta)

It grows 3-4 generations per year and it winter as a larva inside a silky cocoon, inside the cracks of the tree barks. This moth attacks the sprouts, leaves and fruits, causing most of the damage to fruits. the larvae of the first generations attack the sprouts and feed on their insides, inflicting great losses to newly planted orchards and nurseries. The larvae of the 3rd and 4th generations cause significant damage to fruits. The larvae will make their way inside the fruit in the peduncle area and will chew irregular galleries around the seeds. The fruits will stagnate their growth, rot and fall off. The adults will fly around during the following periods: 20th – 30th May, 10th – 20th June, 20th – 30th July and 1st – 10th September.

almond amygdalus communis - oriental fruit moth

Prevention and control measures:

  • Cutting off and destroying the affected plant organs
  • Using sticky traps
  • Chemical treatments to be applied during the active flight phase of the adults, using: Mospilan 20 SG, Karate Zeon 50 CS, Calypso 480 SC, Affirm;

San Jose scale (Quadraspidiorus perniciosus)

This is a polyphagous pest that attacks over 200 plant species. It grows 1-3 generations per year and it winters as a larva on the bark of the affected species. The females and larvae spread on all organs of the affected plants, including the fruits, feeding on the cellular juice of the host plants. If the attack is severe, the protective shields of the insects overlap and suffocate the trees. The trees will stagnate from growing and after 2-3 years it will wilt.

Prevention and control measures:

  • Applying the specific treatments during the vegetative rest period
  • Cleaning the branches with a scrubbing brush
  • Chemical treatments, using Kohinor, Actara, Calypso, Faster 10 CE, Movento 100 SC;

Aphids

This is a polyphagous pest that migrates from one plant to another or from one species to another. These grow on the spontaneous flora and then move to the planted species. It can be seen as a colony on the inferior side of the leaves, on flowers or inflorescences or on young sprouts. The insects sting and suck the cellular juice, inflicting stress to the plant. If the attack is severe, it leads to a decrease in the plant’s resilience towards diseases.

almond amygdalus communis - aphids

Prevention and control measures:

  •  Treatments using Teppeki, Confidor Energy, Mospilan 20 SG, Actara 25 WG;

Plum fruit moth (Cydia funebrana)

This pest species attacks stone fruit trees. It grows 2 generations per year and winters as a cocoon under the barks of the trees or under different sheltered places. The larvae make their ways inside the fruits where they feed with the pulp and seeds. The affected fruits stop growing and fall on the ground. The larvae will continue eating the fruits even if these have already fallen. After feeding, the larvae come out of the fruits and seek for a suitable wintering spot.

almond amygdalus communis - plum fruit moth

Prevention and control measures:

  • Chemical treatments, using Laser 240 SC, Karate Zeon 50 CS, Faster 10 CE, Affirm, Coragen

Weevil (Sciaphobus squalidus)

This is a dangerous species that affects the sprouts and flower buds. It grows a generation once every 2 years and it winters as an adult inside the soil’s superficial layer. The adults emerge during spring, climb in the trees and feed on the sprouts and flower buds. The larvae are not harmful for the trees as they feed on the roots of the spontaneous herbaceous plants.

almond amygdalus communis - weevil

Prevention and control measures:

  • Earthing up the soil during autumn
  •  Chemical treatments using Mavrik, Reldan, Pyrinex 25 CS, Actara 25 WG, Calypso 480 SC;

Apple blossom weevil (Anthonomus pomorum)

It grows one generation per year and it winters as an adult under sheltered spots (tree barks). The adults emerge in spring and feed with the young leaves. The females lay their eggs inside the flowers or flower buds. The larvae feed with the flowers or flower buds’ interiors.

almond amygdalus communis - apple blossom weevil

Prevention and control measures:

  • Chemical treatments using Mavrik, Reldan, Pyrinex 25 CS, Actara 25 WG, Calypso 480 SC;

Thrips

These are small-sized insects, barely visible for the naked eye, that attack a large number of crop or orchard plants. They colonize the growing tips of the plants, the flowers, leaves and determine a stagnation in the plant’s growth.

almond amygdalus communis - thrips

Prevention and control measures:

  • Treatments using Vertimec, Mavrik 2 F, Match, Karate Zeon;
  • Using sticky traps.

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