Diseases And Pests Of Ornamental And Fruit Trees In The Season

Diseases And Pests Of Ornamental And Fruit Trees In The Season
Diseases And Pests Of Ornamental And Fruit Trees In The Season
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The development of diseases and pests on ornamental and fruit and berry plants in the 2013 season had its own characteristic features. Late melting of snow and untimely thawing of the soil led to the fact that the root system of plants could not supply moisture and nutrients to the crown, quickly restoring the natural function of protecting against stem pests - resinification. The hot weather that followed in May contributed to the rapid and intense flight of stem pests that caused considerable damage to coniferous crops (pines, spruces, firs).

In large deciduous trees, planted in the fall 2012 - spring 2013 season, this weather led to bud opening and the appearance of leaf blades, while the root system, being in the frozen soil, could not provide them with water and nutrients. This situation has led to a large mortality in new plantings (especially fruit trees).

Long rains and cool weather in the second half of summer somewhat slowed down the development of stem pests, but contributed to the intensive development of fungal diseases of foliage and needles.

Bark beetle typographer
Bark beetle typographer

Bark beetle typographer

A long-term outbreak of development of the typographer bark beetle (Ips typographus L.) continued on Norway spruce. Not only freshly planted trees suffered, but also old-growth stands, especially in monoculture conditions.

Drill meal for ordinary spruce
Drill meal for ordinary spruce

Drill meal for ordinary spruce

On Scots pine and cedar pine, mass colonization of young plantings with large (Tomicus piniperda L.) and small (Tomicus minor Hart.) Pine beetles and other stem pests was noted.

In May, Scots pine needles were actively damaged by the larvae of the common pine sawfly (Diprion pini L.).

Larvae of common pine sawfly on mountain pine after chemical. processing
Larvae of common pine sawfly on mountain pine after chemical. processing

Larvae of common pine sawfly on mountain pine after chemical. processing

Drying of the annual growth of mountain pine at the end of May
Drying of the annual growth of mountain pine at the end of May

Drying of the annual growth of mountain pine at the end of May

The drying up of the annual growth of mountain pine at the end of May was caused by various reasons: in some cases, the tops of the May shoots were damaged by the summer shoot (Rhyacionia duplana Hb.) - a caterpillar emerging from eggs laid in spring, which gnaws into the shoot, leading to its bending down and drying out. In other cases, the drying of the annual growth (especially in the mountain pine) was of fungal origin (presumably, it was affected by the fungus Sphaeropsis sapinea (Fr.) Dyko & B. Sutton (syn. Diplodia pinea (Desm.) Kickx.)).

Thuja false shield (Parthenolecanium fletcheri L.) massively developed on thujas. Treatments with systemic insecticides (in particular, Aktara) made it possible to stop the development of this pest.

Thuya false shield on thuja
Thuya false shield on thuja

Thuya false shield on thuja

Thuya false shield on thuja
Thuya false shield on thuja

Thuya false shield on thuja

On horse chestnut, caterpillars of the Ohrid miner (Cameraria ohridella Deschra at Dimič), as well as reddish-brown leaf spot (causative agent - fungus Phyllosticta paviae Desm.) Are widespread and are harmful, the characteristic symptoms of which are the appearance of extensive brown spots, leading to premature leaf fall.

Ohrid miner mines on horse chestnut
Ohrid miner mines on horse chestnut

Ohrid miner mines on horse chestnut

Red-brown leaf blight on horse chestnut
Red-brown leaf blight on horse chestnut

Red-brown leaf blight on horse chestnut

On the small-leaved linden, the development of thyrostromosis continues (the causative agent is the fungus Thyrostroma compactum (Sacc.) Höhn.) - a fungal disease of branches and trunks, leading to the drying out of the annual growth and the appearance of ulcers at the base of the branches and on the trunks. Of the leaf spots on linden, the greatest damage this year was caused by brown spot (the causative agent is the fungus Septoria tiliae Westend.).

Linden thyrostromosis
Linden thyrostromosis

Linden thyrostromosis

Slimy sawfly on linden
Slimy sawfly on linden

Slimy sawfly on linden

In recent years, the number of pests has been increasing in the linden mucous sawfly (Caliroa annulipes Klug.). The linden mite (Lithocolletis issikii Kumata), the linden gall mite (Eriophyes tiliae Nal.), And the linden vein mite (Eriophyes tiliae var. Nervalis Nal.) In a weak, rarely medium degree were also noted on the linden.

On elms, tyrostromosis (see above, linden tyrostromosis) and graphiosis (Dutch disease, ophiostomosis (caused by the fungus Ophiostoma ulmi (Buisman) Nannf.) Were observed). On the foliage of the elm, grayish leaf spot was observed (the causative agent was the mushroom Phyllosticta lacerans.) Among the pests - the elm mesh mite (Aceria brevipunctatus Nal.) in a moderate to strong degree, a complex of leaf-gnawing pests in a weak degree.In addition, stem pests - elm sapwoods of the genus Scolytus, carriers of the Dutch disease were noted on the trunks of individual specimens.

Ilm sapwood of the genus Scolytus on an elm tree
Ilm sapwood of the genus Scolytus on an elm tree

Ilm sapwood of the genus Scolytus on an elm tree

Dutch elm disease
Dutch elm disease

Dutch elm disease

Darkening of the vascular ring in elm lesions with Dutch disease
Darkening of the vascular ring in elm lesions with Dutch disease

Darkening of the vascular ring in elm lesions with Dutch disease

On Norway maple, black spot was strongly observed (causative agent - fungus Rhytisma acerinum (Pers.) Fr.). In places where last year's foliage is not removed, this disease manifests itself annually.

Norway maple, black leaf spot
Norway maple, black leaf spot

Norway maple, black leaf spot

2003-2004 in Moscow and the Moscow region, a mass weakening and drying of ash began. On the trunks of ash, the settlement of the ash emerald narrow-bodied goldfish (Agrillus planipennis Fairmaire) is often noted. Ash goldweed belongs to the group of aggressive stem pests capable of settling on living, even not weakened trees. The small variegated ash beetle (Hylesinus fraxini Parz.), Inhabiting the tops and large branches of ash, is a frequent companion of the golden beetle in Moscow.

Hawthorn eggs on a pear
Hawthorn eggs on a pear

Hawthorn eggs on a pear

Black cancer on apple tree
Black cancer on apple tree

Black cancer on apple tree

This year, the hawthorn butterfly (Aporia crataegi L.) continued to cause significant damage to Rosaceae, especially fruit crops.

On apple trees, black cancer is more and more often observed (the causative agent is the fungus Botryosphaeria stevensii Shoemaker, syn. Sphaeropsis malorum (Berk.) Berk.), Both in old and young plantings.

Rust develops more intensively on pear leaves every year (pathogens are fungi Gymnosporangium sabinae (Dicks.) Wint. And G. dobrozracovae Mitr.), Especially when growing closely with species of juniper, the main host.

Rust on the pear
Rust on the pear

Rust on the pear

Rust on the pear
Rust on the pear

Rust on the pear

On stone fruit crops, as before, the main danger is represented by such fungal diseases as moniliosis (monilial burn) (causative agent - fungus Monilinia laxa (Aderh. & Ruhland) Honey) - especially on felt cherries, coccomycosis (causative agent - fungus Blumeriella jaapii (Rehm) Arx), and klyasternosporiosis (perforated spot) (caused by the fungus Stigmina carpophila (Lév.) MB Ellis.)

Monilial cherry burn
Monilial cherry burn

Monilial cherry burn

Clasterosporium on cherry
Clasterosporium on cherry

Clasterosporium on cherry

Due to the humid weather conditions and the absence of prolonged heat, in the summer of 2013, compared to previous years, such polyphagous pests as the common spider mite Tetranychus urticae Koch., Many species of aphids, etc., did not show much activity.

Pests and pathogens associated with the habitation of these species were present on different types of tree species, but, as a rule, their number did not exceed the harmfulness threshold.

Thus, knowledge of the main diseases and pests that caused significant damage to woody plants in the current year allows planning and carrying out measures to protect green spaces at the beginning of the next season.

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