DENDROCTONUS MICANS PDF

Most occur on conifers in North and Central America. Dendroctonus armandi native to China and D. Several species are important forest pests, capable of reaching epidemic levels and killing thousands of trees. The genus Dendroctonus contains some of the most destructive forest insects in North and Central America, including the southern pine beetle Dendroctonus frontalis , mountain pine beetle Dendroctonus ponderosae , Douglas-fir beetle Dendroctonus pseudotsugae and the spruce beetle Dendroctonus rufipennis.

Author:Shaktilabar Bragis
Country:Togo
Language:English (Spanish)
Genre:Photos
Published (Last):17 May 2009
Pages:81
PDF File Size:1.61 Mb
ePub File Size:6.46 Mb
ISBN:526-7-91673-545-8
Downloads:74991
Price:Free* [*Free Regsitration Required]
Uploader:Shakazahn



Most occur on conifers in North and Central America. Dendroctonus armandi native to China and D. Several species are important forest pests, capable of reaching epidemic levels and killing thousands of trees. The genus Dendroctonus contains some of the most destructive forest insects in North and Central America, including the southern pine beetle Dendroctonus frontalis , mountain pine beetle Dendroctonus ponderosae , Douglas-fir beetle Dendroctonus pseudotsugae and the spruce beetle Dendroctonus rufipennis.

Mating takes place under the bark prior to emergence and before the adult beetles are fully chitinized. Sibling males normally mate the females incestuous mating. The ratio of males to females is low. Typically the sex ratio is one male per 10 females but can be as low as one male per 45 females. The phenomenon of pre-emergence mating precludes the need for females to attract males. Therefore, there is no adult aggregation pheromone. The adult beetles can remain underneath the bark of the trees in which they developed for long periods, if the conditions for emergence are not suitable.

When emergence does occur, the adults cut round emergence holes through the thin bark that covers the brood system. The emergence holes can be constructed well ahead of the actual emergence and large quantities of powdery frass are ejected.

Emergence can occur over a protracted period, with many beetles using the same emergence hole. The mated females emerge to attack either new trees or unattacked portions of the host tree from which they emerged. Adult flight and, more commonly, walking, play an important part in adult dispersal.

This typically leads to small groups of attacked trees. Sometimes no adult emergence occurs and new brood areas are established in the same tree, along the margins of existing galleries. Successive attacks, over a period of 5 to 8 years, may be necessary to kill a tree, except during outbreaks. Beetle attacks often occur around areas of damage on a tree, which may have been caused by lightning or logging. Attacks are often associated with decreased resin pressure and commonly occur in forked or multi-stemmed trees, just below the branch nodes.

In some countries, there appears to be an association between beetle attack and the occurrence of root disease caused by fungi such as Heterobasidium annosum or Armellaria sp.. However, apparently healthy trees are also commonly attacked. The female bores through the bark and establishes a brood chamber. She clears the resin that accumulates during the attack process by mixing it with frass and expelling it through the entrance hole. The expelled resin mixed with frass is purplish-brown and gives rise to resin tubes, which are characteristic of D.

These can be seen on the bark surface of infested trees. When the female reaches the cambium, she bores upwards for approximately 2 cm, constructs an egg chamber and deposits a cluster of between and eggs. These are covered with frass and wood dust. Then she may produce additional egg chambers, leading to a mix of several larval instars in the same family group, or she may attack other portions of the tree or adjacent trees. Newly hatched larvae feed gregariously, side by side, in a brood gallery that becomes larger as the larvae feed.

The size of the brood gallery varies according to the number of larvae present. A large brood of larvae can construct a gallery that is cm long and cm wide. When several females oviposit close to each other, the individual galleries coalesce. This can cause extensive injury to the tree. The larval colony feeds upwards and outwards from its origin. The frass and dead bodies of siblings are tightly packed into the area behind the feeding front.

The larvae produce an aggregation pheromone; a mixture of trans- and cis-verbenol, verbenone and myrtenol, which sustains larval aggregation. There are five larval instars. When feeding is completed, they move back into the islands of tightly packed frass and construct single pupal chambers. The time required for D. In Great Britain, the time to complete a generation ranges from 10 to 18 months Fielding and Evans, Natural enemies.

CEIG RULES PDF

EPPO Global Database

Life cycle[ edit ] Larvae of Dendroctonus micans The female beetle excavates a tunnel in the bark of a host tree and creates a brood chamber. Any resin that accumulates is mixed with frass droppings and pushed out of the tunnel, creating a purplish-brown mass known as a resin tube. A hundred or more eggs are laid in the brood chamber and the female moves on, either creating another brood chamber near the first or exiting the tree and starting again. There are five larval instars and when the larvae are fully developed, they create individual pupal chambers in the frass and pupate. The total development time varies with temperature and may be one to three years. The new adults may stay under the bark, mining new tunnels and creating new brood chambers, or they may emerge into the open air.

KWASHIORKOR PATHOPHYSIOLOGY PDF

Riesenbastkäfer

Search the Forest Research site Search Search terms in quotes will enable a more specific search e. The biological control programme has been, and continues to be highly successful because of the extraordinary ability of the predator to locate its prey even when there are only a few infested trees in the forest. Rhizophagus grandis. Sense organs that detect chemical signals from prey are located on the antennae, one of which is magnified inset. The rearing system to breed R. In addition, because R.

IMAGEMAGICK CONVERT RASTERIZE PDF

Publications

.

BIOGRAPHY OF INDRA NOOYI PDF

Great spruce bark beetle (Dendroctonus micans)

.

Related Articles