The adult wasp presents a slight sexual dimorphism. The female has a size of 8 to 10 mm in length and wingspan of 18 to 20 mm. Saw antennae. Membranous wings of yellowish color, with very marked nerves. Body with the abdomen as wide as it is long. Black head and yellow thorax with black spots on the back; abdomen also yellow, with a large black spot. The male, somewhat smaller, has a size of 7 to 8 mm and wingspan of 16 to 18 mm. Densely bipectinate antennas. The wings have less marked nerves than in the female. Abdomen one and a half times longer than wide. Head, thorax and abdomen black, except the end of the last segment, which is, like the legs, yellow-reddish.
Setting: Eggs of oval shape and white coloration. They are deposited in isolation in cavities practiced by the female in the needles; the laying consists of between 50 and 130 eggs, supporting each acic between 14 and 16. The eggs are covered by segregations of the female and substances from the own acicular.
Larva: Reaches 22 mm, after passing through 5 stages the male and 6 the female. It has legs in the thorax and 8 pairs of false abdominal legs, above which there are black spots. General yellow-brownish coloration and chestnut-reddish head.
Pupa: Encased in a hard silky cocoon of chestnut color and ovoid cylindrical shape.
It is found throughout Europe, North Africa and Asia.
The biological cycle in this species can hardly be schematized, given its variability.
Like all hymenoptera, it has a holometabolous cycle, passing through the egg, larva, pupa and adult phases.
Adults emerge late in the spring and live only a few days. The females deposit the pine needles; seven to thirty days later, depending on the temperature, the larvae are born; these begin feeding on the same leaves in which the laying was done and they pass in a larval stage between forty and five and sixty days, the males have 5 stages and the females 6 larval stages; Then they weave a cocoon in which they can stay between three days and no less than four years, until they undergo a final transformation in pupa that lasts six to twelve days after which the adult finally emerges.
Species univoltina or bivoltina, because often two generations of Diprion pini occur in the same year, one in spring and another in autumn, and it is also common for simultaneous emergencies of adults of different generations.
It can cause pests on forest species where it causes intense defoliation. The phase responsible for the damage is the larval phase.