Pine sawfly - photos, types and interesting facts

One of the common pests of coniferous forests is a pine sawfly. Hymenoptera insects larvae spoil various species of pines, and during massive outbreaks they destroy part of the trees. The pest is found everywhere from Europe to the Far East, has taken root in the northern part of the USA. Regular population control and comprehensive control measures help prevent the spread of sawflies.

Morphological description

Pine sawfly (Diprionidae) - a family of sedentary percussion insects, including 140 species. Sawfly larvae feed on needles, causing significant damage to plants. A characteristic feature of the group of sitting and peritoneum is a wide jumper between the chest and abdomen. The size of the imago is 6-10 mm. The body is oval, convex. Externally, sawflies are similar to wasps and bees, they belong to the same order - hymenoptera.

Interesting fact. The name of the suborder "Sawers" comes from the form of the ovipositor of insects. In most species, it looks like a saw blade.

The photo shows that pine sawflies clearly show sexual dimorphism. Females are larger, body color is yellow or brownish. Black spots on the back, scutellum, and abdomen form variable patterns. Antennae serrate, composed of 19-20 segments. The sawtooth ovipositor has teeth of various shapes and sizes.

The male is smaller than the partner, its length is 6-8 mm. The body is completely black, only the legs are orange. The integument is smooth and shiny. Antennae black-brown, cirrus with 18-20 pairs of ridge processes. The head and chest are covered with puncture and gray hairs. Hind wings darkened at the edge.

Larvae

Adults do not eat; larvae make vital energy reserves. They are called false caterpillars. Outwardly, they look like caterpillars - butterfly larvae. The difference is a large number of abdominal legs - 8 pairs, for caterpillars - 5 pairs. Body length 25-28 mm. Color depending on the type is green-yellow or dark gray with dark spots and stripes. Larvae live in large families of 2030 individuals. They eat together, and when the needles on the branch ends, they move to a new site.

Information. Male false caterpillars change 5 ages, and female - 6.

The excrement of pine sawfly larvae is distinguished by a peculiar rhomboid shape. With a significant spread of pests in the forest, a rustling is heard caused by a drop in caterpillar secretions. A thin layer of waste can be found under the trees. The food period lasts from August to October. Most of the larvae then descend into the soil for pupation. Part of the colony is hidden in the cortex, where it is preparing for the formation of a cocoon.
In this phase, the larva is called anonymph. Her body contracts and transforms, her abdominal legs disappear. The cocoon of insects is cylindrical in shape, the ends are blunt rounded. Brown color. Larvae of the first generation in the state of eonymph spend several days, and the second - 8-9 months. They survive the winter months while in a cocoon.

Breeding

Sawers give two generations per year. The first years of imago begin in April-May, then the first clutch appears.Insects are completely transformed. They go through 4 stages in stages:

• egg;
• larva;
• pupa;
• imago.

The sawfly eggs are elongated, white or greenish, oval in shape. Size - 1.6-1.7 mm. The female ovipositor makes cuts in the pine needles and places one egg in them. There are 6-10 pieces per needle, on top they are covered with a green foamy substance. During her life, each female lays 30-120 eggs. First generation adults appear in late July and early August. They do not need food, insects immediately begin to mate. False caterpillars, which appeared from August to October, fall into the winter diapause.

Larvae wake up in the spring, depending on the region in April-May. After a few days, they become pupae, and then adults. The development temperature is affected by air temperature:

• at 25 ° -26 ° - 15-25 days;
• at 13 ° -10 ° - 40-60 days

Attention. Cocoons of the first generation are placed openly on the branches of pines, the second - in the forest litter.

Types of pine sawflies

The pests of pine needles live everywhere, but the most diverse species occur in temperate regions. Among the most numerous and harmful insects stand out: the ordinary pine sawfly and the red pine sawfly.

Common pine sawfly (Diprionpini)

The main fodder plant is ordinary pine. Larvae prefer young trees. The pest is widespread throughout Europe, in North Africa, in Turkey. Its habitat captures Siberia to Lake Baikal. Females are yellow in color; there are black spots on the chest and segments of the abdomen. Male black with comb antennae. Larvae are pale yellow with a brown head. Above each pair of abdominal legs is a black spot in the form of a semicolon.

In the northern part of the habitat, insects give 1 generation, in the southern regions 2 generations are replaced per year. The ordinary pine has large needles and grows in conditions favorable for the sawfly. He prefers this type of coniferous species.

Red pine sawfly (Neodiprionsertifer)

The name was given to the species by the red females of the sawfly, the male adult black. Forests are harmed by larvae that appear in May. At the first age they feed on the pulp of needles, later they completely eat up the needles. With mass reproduction, 50-100 individuals can feed on one branch. Along the back there is a light strip with a black edging. On the sides above the spiracles there is a wide dark stripe bounded on both sides by a light border. The head of the larva is black.

Insects give 1 generation per year. Adult years are observed in August-September. The species Neodiprionsertifer is characterized by two biological forms. The offspring of one winter in the form of eggs, and the second - larvae in a cocoon. Outbreaks of mass breeding last 1-3 years, occur in natural forests and artificial pine stands.

Interesting fact. In addition to sexual reproduction, a parthenogenesis is observed in the red pine sawfly. The female lays unfertilized eggs, from which only males emerge.

Malware

Young false caterpillars eat pine needles from the sides, leaving the middle vein. Adults destroy the needles completely, to hemp. Their appetite increases with each week of development. Larvae damage not only the needles, but also the bark of the branches. During the growing period, the larva eats 30-40 pine needles. Damaged needles turn yellow and dry.

In favorable conditions - warm and dry weather, outbreaks of mass reproduction of pests occur. They are observed on young stands located on high ground. Also, an increase in population occurs on the clear edges of pine forests. An outbreak of reproduction in two generations lasts 3-3.5 years. It may be delayed or interrupted due to diapause.

Attention. Repeated attack by sawflies significantly weakens the tree. The likelihood of other pests - bark beetles - is increasing.

Methods of struggle

Limit the number of pests and prevent massive outbreaks helps surveillance and control of the pine sawfly.In late spring and early summer, soil under the trees is inspected for excrement of larvae. Typical tree damage is studied - drying, curly and yellowing needles. On low young plants, larvae can be seen. They sit 2-3 individuals on each needle. Anxious pseudo-caterpillars raise the front of the body. The number of cocoons in the forest litter is also counted.

Mechanical methods

Destruction of pests in their own area can occur by manual collection. Work should be done with gloves to protect the skin from exposure to pseudo-caterpillar secretions. Mechanical methods include the installation of hunting belts. A trap located on a pine trunk acts on larvae descending for pupation.

There are two types of belts:

1. Sticky - the outer layer of the trap consists of an adhesive substance that does not dry out for a long time.
2. Destructive - the tissue is impregnated with an insecticide that kills insects.

Forestry measures

• It is recommended to create mixed forests with evenly closed stands.
• The device of the tier from the bush. Pest cocoons are susceptible to fungal and bacterial diseases, spreading with high humidity.
• Enrichment of nitrogen-poor sandy soils by planting perennial lupine.
• When laying new nurseries, Crimean pine should be planted. Which is less prone to attack by sawflies.

Chemicals

For mass infection of trees, systemic insecticides (Karbofos, Chlorofos) and chitin synthesis inhibitors Tsiromazin and Buprofesin are used.

Biological impact

The pine sawfly has many natural enemies. Riding wasps often parasitize on pupae of insects, birds willingly eat larvae. Measures to combat pine sawfly include:

• pest infection with viral infections;
• attraction of insectivorous birds;
• breeding and use of tahins, ants, real riders;
• setting pheromone traps;
• the use of biological insecticides.

Interesting fact. There are 95 species of entomophages that live off sawflies. All of them help in the destruction of the pest.

On the plot you can treat the trees with infusion based on garlic, tobacco, tomato stalks.