Sweet chestnut treatments, common diseases and pests of this fruit tree

sweet chestnut castanea sativa

sweet chestnut castanea sativa

The sweet chestnut (Castanea sativa) is a species that originated from countries near the Mediterranean Sea. It grows as a vigorous tree, 15-25-m high and it grows large, wide, pyramidal, globose crowns. It grows as develops manually in areas where the average annual temperatures exceed 9 degrees Celsius. It prefers long and warm autumns as it is sensitive to sudden frosts. The sweet chestnut can have a decorative role, or it can be grown as a crop. The sweet chestnuts contain starch, vegetal fibers, protein, fats, potassium, phosphorus, magnesium, Sulphur, calcium and vitamins (A, B1, B2, E, C).

Main diseases

Chestnut blight, caused by Cryphonectria parasitica

This is the most dangerous disease for the sweet chestnut crop. It originated from the United States of America, where it spread throughout the world, nowadays there are around 76 virus strains. The symptoms are represented by branch and trunk deformations, accompanied by yellow-brown cancerous formations. The leaves turn brown, but remain attached to the tree. The sweet chestnut species planted in Europe and America are very sensitive to these pathogens. The fungus has been identified in most of Europe by 1984 and since then it has decimated the sweet chestnut orchards.

sweet chestnut castanea sativa - chestnut blight

Prevention and control measures:

  • Carefully harvesting the sweet chestnuts, not to warm the plant
  • The treatment is complex and very expensive. Chemical, biological, mechanical methods to be applied
  • Gathering and destroying the affected trees

Root and crown rot, caused by the Phytophthora fungi

The disease is noticeable as the leaves wilt and turn brown. The trees have a slow growth and prematurely dry out. In the lower part of the stem (base part) injuries emerge and these are similar to the ones caused by the bacterial canker. During high humidity periods, these injuries will become covered by a sticky liquid. This disease will emerge if there is an excessive soil humidity.

sweet chestnut castanea sativa - root and crown rot

Prevention and control measures:

  • Rational irrigation
  • Avoiding moist parcels
  • There is no recommended treatment for this disease

Leaf spot, caused by Guignardia aesculi

The first symptoms are represented by the emergence of light-yellow stains. As the disease evolves, the spots turn red and become surrounded by a yellow colored halo. The stains can be solitary or can become united. Black, dot like formations can be observed on the affected tissues and these represent the fungus’ fruitions. If the attack is severe, the tree loses its leaves.

sweet chestnut castanea sativa - leaf spot

Prevention and control measures:

  • There are no recommended treatments against this disease

Main pests

Aphids

These are polyphagous species that migrate from one plant to another or from one species to another. These grow on the spontaneous flora and then move to the cultivated species. These can be observed as colonies on the inferior side of the leaves, on flowers or inflorescences and on young sprouts. These insects sting and suck the cellular juice, inflicting stress on the plant. If the attack is severe, it decreases the plant’s resilience to diseases.

sweet-chestnut-castanea-sativa-aphids

Prevention and control measures:

  • Most of the times, the damages caused by these insects are not enough to justify the insecticide usage, but if the attack is severe, the following products can be used: Teppeki , Confidor Energy , Mospilan 20 SG, Actara 25 WG;

Acari

These are insects that are barely visible for the naked eye. The acari are polyphagous species, that attack a large number of plants and fruit bearing shrubs, both spontaneous and cultivated species. These insects feed on the cellular juice of the affected plants. After the acari attack, the leaves have a parchment like aspect, the flowers abort and the plant will stop growing.

sweet chestnut castanea sativa - acari

Prevention and control measures:

  • Most of the times, the damages caused by these insects are not enough to justify the insecticide usage, but if the attack is severe, the following products can be used: Nissorun 10 WP, Envidor 240 SC, Milbeknock, Vertimec 1.8 EC;

European fruit lecanium

These are polyphagous species that can attack over 200 plant species. It has 1-3 generation 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, feeding on the cellular juice of the host plants. If the attack is severe, the shields that protect the bodies of the insects overlap and choke the plants. These still stop growing and become dried in 2-3 years.

sweet chestnut castanea sativa - european fruit lecanium

Prevention and control measures:

  • Monitoring the attack
  • Chemical treatments to be applied if needed, using Nuprid AL 200 SC, Actara, Calypso, Faster 10 CE, Movento 100 SC;

Chestnut gall wasp, caused by Dryocosmus kuriphilus

This species originated from China and it is the size of 2 poppy seeds. The females lay their eggs inside the leaves and flower buds. After they hatch, the larvae need on the leaves, stems, and flower buds making them to becomes deformed. This is how globular, red, formations appear. This species’ population growth is kept under control by natural predators.

sweet chestnut castanea sativa - chestnut gall wasp

Prevention and control measures:

  • If the attack is severe, the following products can be applied: Laser 240 SC, Novadim Progress, Affirm, Calypso 480 SC;

Japanese beetle (Popillia japonica)

This is a polyphagous species that affect over 300 plant species. The bodies of the adults are green, with a metallic aspect. The adults emerge at the end of the spring season and feed on the leaves. After the attack, the leaves have a serrated aspect.

sweet chestnut castanea sativa - japanese beetle

Prevention and control measures:

  • If the attack is severe, the following products can be used: Laser 240 SC, Mospilan 20 SG, Actara 25 WG, Decis Mega EW 50, Karate Zeon 50 CS;

Cicadas (Magicicada spp)

These are polyphagous species that can cause damage directly or indirectly. These feed on the cellular juice of the sprouts or of the young leaves. After the attack, the plants become deformed and dried. The cicadas can also carry virus diseases or mycoplasmas. Some species make an incision inside young sprouts where they lay their eggs. These incisions represent gateways for other pathogens.

sweet chestnut castanea sativa - cicadas

Prevention and control measures:

  • If the attack is severe, the following products can be applied:  Mospilan 20 SG, Faster 10 CE, Confidor Energy, Actara 25 WG, Nurelle D;

The small chestnut weevil (Curculio sayi)

It grows a generation once every many years and it winters as an adult inside the soil’s superficial layer. The adults climb up in the tree and lay their eggs in the fruits. After hatching, the larvae feed on the interior of the fruits (sweet chestnuts). This is how the production will be affected both in quantity and in quality after this attack.

sweet chestnut castanea sativa - small chestnut weevil

Prevention and control measures:

  • Chemical treatments using: Reldan, Faster, Actara 25 WG, Calypso 480 SC;

Horse-chestnut leaf miner (Cameraria ohridella)

This species is very dangerous and it poses a great threat for anu chestnut species. It has first identified in Macedonia in 1980. It grows more generations per year (2-3) and the larvae are the most dangerous. A female can lay up to 40 eggs. After hatching, the larvae climb on the leaves and consume the parenchyma of the leaves, leaving the 2 epidermises intact. As a result of the attack, the leaves will become dried and will fall off.

sweet chestnut castanea sativa - horse-chestnut leaf miner

Prevention and control measures:

  • Gathering and destroying the leaves that have fallen on the ground
  • Applying a treatment in April-May, before the bloom of the sweet chestnuts. The following products can be used: Reldan, Laser, Calypso, Actara;

Black tree borer (Xylosandrus spp)

This is a pest species that attacks many wooden species. The females chew tunnels inside the stems and thick branches, where they lay their eggs. In severe cases, these can destroy the entire stem. These insects live in a symbiosis with a fungus that helps them digest the cellulose.

sweet chestnut castanea sativa - black tree borer

Prevention and control measures:

  • Cutting off and destroying the affected branches.

Got a question?

Leave a Reply

Your email address will not be published. Required fields are marked *

ASK A QUESTION