Beetles on the lilac

Question: beetles on the lilac

need help !! Lillà infested with beetles. What to do? Apart from that they suck me, can they attack other plants? it cohabits in a very large separate pot in a big terrace together with a wisteria 2 apple trees a beautiful jasmine (or better ... I don't remember what it's called) 2 Mandeville and 2 beautiful cedars of Lebanon. Please help me, I've killed more than 30 in 2 days !!!!

Beetles on the lilac: Answer: beetles on the lilac

Dear Luisella,
the beetles are very beautiful beetles for those who love to collect insets, but unfortunately also very harmful to the plants, as they feed on the leaves as adults, they lay the eggs at the base of the shrubs, from which are born several larvae that bury and eat the roots of young plants; they can stay on the ground even two full years, feeding on the rootlets, to then become adult beetles and fly away, beginning to eat the foliage. In nature, in a wood, the large amount of vegetation of various types, is not particularly affected by the presence of such insects, which often tend as adults to consume the leaves of the trees (it is clear that, even if on a tree there are 10 -15 beetles, can not cause significant damage to the total vegetation of the tree); the larvae, on the other hand, seem to prefer the roots of some annuals, and of most of the plants that we would call pests in the garden (and therefore also here no one worries about the presence of beetle larvae in the woodland, because they do not do visible damage). Another argument is whether these insects live as larvae in a vase on the terrace, from which they emerge as adults, feeding on the leaves of a small shrub. Obviously the quantity of food that your beetles have available is decidedly less than that which they would find in a wood, and therefore even a few adult specimens can visibly ruin a lilac shrub. And not only will the leaves now eat them, with good probability they will go to lay the eggs at the base of your plants, and therefore they will remain for several months in the pots of your terrace, nibbling the roots of your plants. The fight against these pests is not very simple, first of all because most of the insecticides that you find on the market (whether they are traditional insecticides, whether they are insecticides suitable for organic cultivation) work on small insects, which are killed when they are killed. sprays the insecticide on; as beetles tend to be more active at night, it is very difficult to vaporize them with a common garden insecticide. For larvae then, it would still be necessary to unearth them, and if your pots are very large, extracting all the earth they contain in search of larvae could be a big job. In the nursery, however, you find insecticides in the form of granular bait, to be used against terrestrial insects; their use in the garden and in the garden is not recommended, because they kill all the insects present in the earth, even those useful as earthworms; but the vase, I think their action is a little more controllable, as they are scattered on the earth of the vases. But they do nothing against adults, they only work on larvae. Against adults, if they are decimating the leaves of the lily suit, you will find in specialized stores an excellent product for organic farming, based on nematodes (other useful insects that kill larvae and parasitizing adults). They are not everywhere, you can search online, and they certainly cost a few euros more than an ordinary insecticide, but they work well and will completely free you from the problem.