The Cacyreus marshalli (Butler) is a butterfly that belongs to the family Lycaenidae, native to South Africa, arrived in Italy recently, in the late 80s. It is also called the plague of geraniums and pelargoniums, for its ability to kill these and other flowers by laying eggs on the stems. In England it is called Geranium Bronzo. The color is in fact dark brown similar to bronze.
Introduced in Europe probably with some batches of geraniums, it quickly spread first in the Balearic Islands, then later in Spain, Italy and France.
The female lays round, white eggs in the stems and twigs and the larvae are light green, similar to small caterpillars,
eating the contents,
causing the flowers to die.
The male is slightly longer, reaching about 15 mm with a wingspan of 30 mm, while the female measures 12 mm in length and has a wingspan of 24 mm.
It has a long brown proboscis about 3 mm long with which it sucks and pierces.
It is especially noticeable during the hours of full sun, when it is very active, while in the shade it tends to remain motionless in the leaves or on the ground. During the night it does not carry out any activity.
How to defend yourself against Cacyreus marshalli:
We have seen that it destroys geraniums through its larvae which penetrate inside the twigs feeding on the sap of the geranium.
From this photo you can see the brown, now dead part of in geranium.
Chemical control
To defend against this butterfly, some effective products have been put on the market in the years 2008 until 2013: Axoris tablets of Compo or Provado facile of Bayer. However, these products of the type PPO (Protection of ornamental plants) and therefore of free sale, have been withdrawn from the market as a result of a Decree of 2003 because they contain high doses of thiamethoxam and midacloprid and therefore able to damage the plants.
thiamethoxam and midacloprid and therefore capable of harming bees.
Bayer has recently produced a specific insecticide called Calypso Garden Protector AL or Calypso Plus.
Natural Defense
For those of you who, like me, prefer natural defense products, there is an interesting new product that works well. It is the solar cell powered dancing butterfly that flickers all day on geraniums and prevents Cacyreus Marshalli from roosting. On the Internet you can find many of these butterflies at low prices, about 10/15 euros; they have the low price, but they are not worth anything. Instead, the butterfly of the French company Heliobil is absolutely better and, although it costs more (about 32 euros) has given me excellent results.
https://www.heliobil.fr/produit/papillon-volant-incline-soleil/
This is the photo showing the geraniums flourishing with the Heliobil butterfly
And this is the photo of the geraniums without the butterfly.
Larvae were deposited in the trunk and fed on the pulp.
Cacyreus marshalli 
