Description, Biology, Life Cycle, Damage, Common Names, Images
- Host plants: sunflower as well as other Compositae: artemisia, aster, burdock, thistle, chrysanthemum, cineraria, daisy, etc.
- Larva: the neonate caterpillar (*) first presents a rambling phase and feeds on pollen. It then penetrates the floret or drills the fleshy base of the bracts which surrounds the involucre, digs galleries in the medullary parenchyma of the capitulum, gnaws the base of the florets or empties the contents of the seeds. It lives only at the level of the inflorescence, never in the stems.
At the end of its development, it falls to the ground, buries itself a few centimetres, makes a cocoon and pupates, unless it enters into winter diapause.
- At least 3 annual generations in the south of France, often a fourth and even a fifth partial generation as this pyralid is capable of reproducing as long as it finds favourable places to lay and feed.
- The first generation develops end of May-beginning of June at the expense of wild Compositae and particularly Mary's thistle (Silybum marianum L.). On sunflower (for the second generation), laying begins at the start of flowering, once there is pollen emission. A third generation cannot complete its development on sunflowers harvested at the end of August.
However, on later sowings or catch crops, development continues as long as flowers are present and sometimes until the end of November, even the beginning of December.
In the strongly infested zones of the south-east of France, damage occurs mainly on sunflower catch crop, since there, populations of caterpillars on flower heads are more important than for previous generations. Achenes are emptied and the loss can reach 20 to 30% on certain heads (*) . On the other hand, on crop harvested at the end of August, the damage is insignificant due to various natural enemies.
HYPPZ on line : Species (scientific name), Pests (common names), Glossary, Crops.