Psylla pyri
Encyclopedia
Psylla pyri is one of the most important pear
phytophagics; because of the numerous chemical interventions, its dangerousness is increased, reducing the phytopathogenics's populations of this bug
. It is not, however, considered a harmful bug since it is easily censurable with simple interventions, which have favored a resumption of the Psylla's natural enemies.
Psylla's adults are long, around 2.5-3 mms, and of ochre
or brownish color; the wings are transparent and positioned to sloping roof on the body.
The larva
e are flattened and of yellowish-orange color, that darken with time to a brown-blackish color.
In the juvenile stadiums they will cover of honeydew
, to protective purpose; the egg
s will cover too of honeydew and are of yellow-orange color, besides, are of pointed form to an extremity, while in the other there is a tail.
Psylla colonizes the buds, the young leaves
, the young branches and, sometimes, the fruits too.
The damages can be direct and indirect: the first ones concern the vegetative arrests and deformations, with small necroses
on the buds and on the leaves, following the punctures; the seconds provoke abundant production of honeyedew that provokes asphyxias on the green organs and scorching on the tissues. Besides the honeydew depreciates the fruits and it makes useless the treatments; the honeydew, finally, facilitate the establishment of the mushroom
s, that decrease the photosynthetic output, altering the metabolism
of the plant
.
Psylla is a vector of illnesses too, like the Pear's Blackberry.
This bug winters as adult and it completes 5 generations a year; activity is taken back in March, with superior temperatures to 10 °Cs.
The intervention thresholds are:
- treatments, in presence of honeydew or damage, on the fruits up to half June;
- treat, always in presence of honeydew or damage, in relationship among the N° of infesting throws by Psylla and by Anthocorids, that it must be equal to 5:1; if superior, it intervenes it (from half of June in then).
Struggle's techniques foresee:
- in presence of egg
s, with eggcide (Diflubenzuron, Teflubenzuron) or White Oils, in spring-summer;
- in presence of larvae, with Abamectina, preceded by washing's treatments with detergents and water, within the end of May.
The struggle foresees the use of biological products, like Bacillus thuringiensis
, in substitution to the chemical products.
Among the Psylla's natural enemies, its remember them:
- Anthocorids Hemiptera
ls, genus Anthocoris (nemoralis and nemorum), predators of all Psylla's stadiums; genus Orius, larvae and adults Psylla's predators; Anthocorids complete 2-3 generations a year and winters as adults;
- Dipteral Sirfidis and Cecidomidis;
- Neuropteral Crisopidis, Miridis
Hemiptera
ls and Nabidis
;
- Prionomitus mitratus, parasitic Himenopterus of the Psylla's preimmaginal stadiums.
Pear
The pear is any of several tree species of genus Pyrus and also the name of the pomaceous fruit of these trees. Several species of pear are valued by humans for their edible fruit, but the fruit of other species is small, hard, and astringent....
phytophagics; because of the numerous chemical interventions, its dangerousness is increased, reducing the phytopathogenics's populations of this bug
Hemiptera
Hemiptera is an order of insects most often known as the true bugs , comprising around 50,000–80,000 species of cicadas, aphids, planthoppers, leafhoppers, shield bugs, and others...
. It is not, however, considered a harmful bug since it is easily censurable with simple interventions, which have favored a resumption of the Psylla's natural enemies.
Psylla's adults are long, around 2.5-3 mms, and of ochre
Ochre
Ochre is the term for both a golden-yellow or light yellow brown color and for a form of earth pigment which produces the color. The pigment can also be used to create a reddish tint known as "red ochre". The more rarely used terms "purple ochre" and "brown ochre" also exist for variant hues...
or brownish color; the wings are transparent and positioned to sloping roof on the body.
The larva
Larva
A larva is a distinct juvenile form many animals undergo before metamorphosis into adults. Animals with indirect development such as insects, amphibians, or cnidarians typically have a larval phase of their life cycle...
e are flattened and of yellowish-orange color, that darken with time to a brown-blackish color.
In the juvenile stadiums they will cover of honeydew
Honeydew
Honeydew may refer to:* Honeydew , a cultivar group of melon* Honeydew , a sugar-rich sticky substance secreted by aphids and some scale insects* Honeydew, California, a town* Bunsen Honeydew, a fictional character from The Muppet Show...
, to protective purpose; the egg
Egg (biology)
An egg is an organic vessel in which an embryo first begins to develop. In most birds, reptiles, insects, molluscs, fish, and monotremes, an egg is the zygote, resulting from fertilization of the ovum, which is expelled from the body and permitted to develop outside the body until the developing...
s will cover too of honeydew and are of yellow-orange color, besides, are of pointed form to an extremity, while in the other there is a tail.
Psylla colonizes the buds, the young leaves
Leaf
A leaf is an organ of a vascular plant, as defined in botanical terms, and in particular in plant morphology. Foliage is a mass noun that refers to leaves as a feature of plants....
, the young branches and, sometimes, the fruits too.
The damages can be direct and indirect: the first ones concern the vegetative arrests and deformations, with small necroses
Necrosis
Necrosis is the premature death of cells in living tissue. Necrosis is caused by factors external to the cell or tissue, such as infection, toxins, or trauma. This is in contrast to apoptosis, which is a naturally occurring cause of cellular death...
on the buds and on the leaves, following the punctures; the seconds provoke abundant production of honeyedew that provokes asphyxias on the green organs and scorching on the tissues. Besides the honeydew depreciates the fruits and it makes useless the treatments; the honeydew, finally, facilitate the establishment of the mushroom
Mushroom
A mushroom is the fleshy, spore-bearing fruiting body of a fungus, typically produced above ground on soil or on its food source. The standard for the name "mushroom" is the cultivated white button mushroom, Agaricus bisporus; hence the word "mushroom" is most often applied to those fungi that...
s, that decrease the photosynthetic output, altering the metabolism
Metabolism
Metabolism is the set of chemical reactions that happen in the cells of living organisms to sustain life. These processes allow organisms to grow and reproduce, maintain their structures, and respond to their environments. Metabolism is usually divided into two categories...
of the plant
Plant
Plants are living organisms belonging to the kingdom Plantae. Precise definitions of the kingdom vary, but as the term is used here, plants include familiar organisms such as trees, flowers, herbs, bushes, grasses, vines, ferns, mosses, and green algae. The group is also called green plants or...
.
Psylla is a vector of illnesses too, like the Pear's Blackberry.
This bug winters as adult and it completes 5 generations a year; activity is taken back in March, with superior temperatures to 10 °Cs.
Struggle methods
It performs criteria of guided and integrated struggle; treatments are effected only to the overcoming of the intervention threshold and considering the presence of the Psylla's natural enemies.The intervention thresholds are:
- treatments, in presence of honeydew or damage, on the fruits up to half June;
- treat, always in presence of honeydew or damage, in relationship among the N° of infesting throws by Psylla and by Anthocorids, that it must be equal to 5:1; if superior, it intervenes it (from half of June in then).
Struggle's techniques foresee:
- in presence of egg
Egg (biology)
An egg is an organic vessel in which an embryo first begins to develop. In most birds, reptiles, insects, molluscs, fish, and monotremes, an egg is the zygote, resulting from fertilization of the ovum, which is expelled from the body and permitted to develop outside the body until the developing...
s, with eggcide (Diflubenzuron, Teflubenzuron) or White Oils, in spring-summer;
- in presence of larvae, with Abamectina, preceded by washing's treatments with detergents and water, within the end of May.
The struggle foresees the use of biological products, like Bacillus thuringiensis
Bacillus thuringiensis
Bacillus thuringiensis is a Gram-positive, soil-dwelling bacterium, commonly used as a biological pesticide; alternatively, the Cry toxin may be extracted and used as a pesticide. B...
, in substitution to the chemical products.
Among the Psylla's natural enemies, its remember them:
- Anthocorids Hemiptera
Hemiptera
Hemiptera is an order of insects most often known as the true bugs , comprising around 50,000–80,000 species of cicadas, aphids, planthoppers, leafhoppers, shield bugs, and others...
ls, genus Anthocoris (nemoralis and nemorum), predators of all Psylla's stadiums; genus Orius, larvae and adults Psylla's predators; Anthocorids complete 2-3 generations a year and winters as adults;
- Dipteral Sirfidis and Cecidomidis;
- Neuropteral Crisopidis, Miridis
Miridae
The large and diverse insect family Miridae contains the plant bugs, leaf bugs, and grass bugs, and may also be known as capsid bugs. It is the largest family of true bugs belonging to the suborder Heteroptera, with over 10,000 known species and new ones constantly being described...
Hemiptera
Hemiptera
Hemiptera is an order of insects most often known as the true bugs , comprising around 50,000–80,000 species of cicadas, aphids, planthoppers, leafhoppers, shield bugs, and others...
ls and Nabidis
Nabidae
The insect family Nabidae contains the damsel bugs. The terms damsel bug and nabid are synonymous. There are over 400 species. They are soft-bodied, elongate, winged terrestrial predators. Many damsel bugs catch and hold prey with their forelegs, similar to mantids...
;
- Prionomitus mitratus, parasitic Himenopterus of the Psylla's preimmaginal stadiums.