The Insect
The Mediterranean spotted chafer, Oxythyrea funesta, is a fairly small species belonging to the order Coleoptera and family Scarabaeidae, subfamily Cetoniinae.
This chafer holds many small irregularly arranged white spots on the elytra, while its size does not exceed 10 mm in length. It is present throughout the Mediterranean basin. The adults are diurnal and feed on pollen and nectar from flowers, many herbaceous and arboreal species. During the night, adults hide in the ground to cause significant damage when conditions are favorable for their development on stone Rosaceae such as peach and pome Rosaceae such as apple and pear and on all citrus species. Also, this polyphagous insect threatens ornamental plants, specifically roses during flowering, by consuming the stamens or damaging the pistils, and the larvae of Oxythyrea funesta feed on the roots of ornamental flowers.
Males have four white dots in the middle of the ventral side of the abdomen, while in the case of females the abdomen is black and rounded. Young adults can be observed from autumn on sunny days from April to September, but their greatest activity is in spring with an optimum of observation in May and June, following a long period of hibernation. The larva develops in decomposing organic plant matter and in compost.
Damage
In Algeria, the damage caused by the chafer has been steadily increasing for three years. The latter is observed in Rosaceae, especially during the dry seasons (Figure 1). The flowering of fruit trees in the current year has seen heavy attacks and some farmers have reported the loss of almost all the flowers (Figure 2).
Control
To fight against the growth of Mediterranean spotted chafer, one must note that it is difficult to use insecticides, because they cannot be applied during flowering to avoid affecting bees or other auxiliaries. There are a few ways to control Oxythyrea funesta, such as fern manure which seems to have a repellent action, so female pheromones can be an alternative control method, which are traps to attract these male beetles. Regularly these pheromones should be cleaned because of the attractive aroma of dead females in the traps a greater number of male Oxythyrea funesta will be attracted.
A cultural technique was proven remarkably efficient on this insect and consists of placing white cups half filled with water; the insects thus trapped in the cups can no longer come out (Figure 3).
Figure 3: Trapping of rose chafer in white cups