Hypera postica
The larvae, which are apodous, are about 1 cm long green in colour with a longitudinal white stripe down their back.
The adults measure between 4 and 6.5 mm wingspan, like sitones, but with a longer rostrum*.
- Rostrum: part of theinsect that
between the eyes
Symptoms on alfalfa
On the upper parts of the plant: consumption of the leaf blade (not attacking the veins).
Period of presence
Script error: No such module "Période de risque".
Larvae :
Spring and pupate in vegetation in early summer.
Adults: do not complete their cycle on alfalfa, first egg-laying possible in autumn, they do not return until the following the following spring to lay eggs in buds, stems and petioles (in a small hollowed small cavity)
Observation method
A watch out for, especially in mild winters when early attacks may be to be feared.
Look for for possible notches on the foliage.
Technical and agronomic management advice
Pre-cutting in April: reduces the larvae population
Favour mixed sowing if inoculum has already caused a problem
Regulated by a parasitic wasp: Bathyplectes curculionis, which attacks larvae
Pressure level
Low : 1 to 2 bites on average per leaflet
Average: More than 2 bites on average per leaflet
High : > 5 bites - defoliation in 2nd or 3rd year
Pressure levels are given for information only and do not accurately reflect the severity of infestation at any given time or subsequent damage. Other factors specific to the crop and the dynamics of the development of symptoms or infestations come into play.
Cultures and produces
This article was written in partnership with <a href="https://www.agrifind.fr/alertes/luzerne/luzerne-phytonome">Agrifind</a> and <a href="https://www.terresinovia.fr/">Terres Inovia</a>.
