Information

Agricultural entomology: Poplar awl

Agricultural entomology: Poplar awl

Classification and host plants

Class: Insects
Order: Beetles
Suborder: Polyphages
Family: Curculionidae
Genus: Cryptorhynchus
Species: C. lapathi L.

Bibliographic reference:
Phytopathology, agricultural entomology and applied biology” – M.Ferrari, E.Marcon, A.Menta; School edagricole - RCS Libri spa

Host plants: Poplar, Willow, Birch, Alder.

Identification and damage

The Poplar weevil is a xylophage beetle quite widespread in Italy, especially on the Poplar but also on other plants of landscape interest.
The adults (about 6-9 mm in length) are brown-rusty in color, with a yellow-ocher band in the distal part of the elytra; the livery is completed with yellowish patches, more or less extended, in the front part of the body.
The larvae, typically arched, are apod and whitish with the reddish head.
The greatest damage occurs on the young plants (nursery); however, it can also occur on dwelling plants and even adults.
The damage is caused by both the adult and the larvae.
The adults make annular incisions along the trunk or on the young branches, feeding on the young peel; the damage can cause either the death of the overlying part, if the decortication is extensive and complete, or a serious weakening of the organ. In these cases, a constriction forms which can cause the branch to break.
These incisions are very serious, especially if they occur on young plants which can even die; if erosions occur on organs of adult plants, generally the attack remains localized. The damage done by the larvae is equally serious; in fact they dig cortical tunnels, both longitudinally and transversely, causing a noticeable weakening of the attached woody organs; these can also dry out if the tunnels assume an annular trend with complete degeneration and disconnection of the conductive tissues and of the gearbox.
In the case of tunnels centered near a lateral sprout, it fades and dries up. In the young organs the galleries deepen to the central medulla.

Biological cycle

The Poplar weevil overwinters: at the egg stage, in the northernmost regions, in wells dug by the females in the rind, or in the ravines of the same; at the young larva stage, in the warmer regions where the flicker of adults is earlier and the exposure is anticipated.
Adults flicker from early June until the end of July; the oviposition can last until autumn.
After mating, the females lay in the rind; the eggs can overwinter, originating the larvae in the following spring, or they can originate the larvae already at the end of the summer of the 1st calendar year. In any case, the young larvae begin their activity causing the damage described; the woody organs generally react to larval attack, with slight swelling of the affected area.
The maturity of the larvae is reached in the summer of the second calendar year; in some northern areas it continues for the 3rd calendar year.
The awl therefore completes one generation every 1-2 years.

Poplar Awl Adult - Cryptorhynchus lapathi L. (photo Gyorgy Csoka www.forestpests.org)

Poplar Awl Larva - Cryptorhynchus lapathi L. (photo Gyorgy Csoka www.forestpests.org)

Fight

The fight against the Poplar Weevil is chemical; however it also makes use of agronomic practices. Agronomic practices consist essentially in the destruction of seriously affected plants or organs, to avoid increasing the potential for infestation. The chemical struggle is carried out only in the presence of strong infestations; it is directed against the larvae, before they deepen in the wood, at the vegetative restart. The execution technique involves direct interventions to the woody organs which are sprayed with insecticide solutions.


Video: ICAR JRF Entomology Questions PART-4. BY AGRICARE AS. ICAR-JRF, IBPS-AFO IGKV-CET, BHU-PET. (January 2022).