Oziorrinco: larvae in the soil

Oziorrinco: larvae in the soil

There are two beetles which have similar larvae and which can cause serious damage to the crops in our garden: oziorrinco and beetle. We have already talked about the beetle larvae, let's now go into the damage caused by the oziorrinco and possible biological defense strategies.

The adult insects of this beetle lay eggs in soils rich in organic matter decomposing, which is why they generally infest fertile and cultivated areas and we often find them in the compost heap.

From the eggs come out the larvae of oziorrinco, which from the ground will also eat the roots of the plants, causing problems for horticultural crops. It is not easy to defend against this threat with biological methods because the larva is found in the ground and therefore products that act by contact have little chance of hitting the target, but let's see how we can defend ourselves from the oziorrinco.

Recognition of the oziorrinco

Adult individuals of oziorrinco (otiorhynchus) have a black body, possibly dotted with white, and are about one centimeter long. The adult insect hides in the stem of the plants, while the larva digs into the ground.

L'oziorrinco has larvae similar to those of various beetles, compared to the aforementioned beetle it has smaller dimensions, it is recognized by the black head, while the beetle larvae have a red head and legs. It is not particularly useful for cultivation purposes to distinguish between the two species, since the larvae do similar damage and fight in the same way.

However, it is not easy to distinguish the larvae from the many other beetle larvae, so when in doubt it is better to avoid unnecessary killing. There are also rare and protected insects. It would also be important to know recognize the golden cetonia larvae, which is a useful insect, as it acts by chewing and digesting organic matter, making it a terrific helper in composting. This beetle therefore does a similar job in some ways to that of earthworms. The larvae of cetonia are really very similar to those of the beetle, but have tiny and atrophied legs, so they can be recognized in a simple way by paying attention to the forelimbs, while the larvae of oziorrinco are apods.

Characteristics of the beetle

Oziorrinco (Otiorhynchus) is a beetle of the genus of weevils. To be precise, there are several species of this beetle, the most widespread is called otiorhynchus rugosostriatus and it is the one that most often annoys the garden.

It is worth mentioning too the oziorrinco of the vine is the oziorrinco of the olive tree, even if they are insects that damage plants less, because their action is above all that carried out by adults on the leaves, except for really consistent attacks, there are no problems for the plant.

Fortunately, this insect reproduces only once a year, usually in summer. The larvae remain in the ground overwintering and in spring there will be the first flights of adult beetles.

Damage caused by the oziorrinco

The roach larvae live in the soil, from which they pass to devour the roots plants, even killing them. The attack of this beetle comes from underground, so no caterpillars are seen arriving, but the problem is recognized by the decay of the plants and the presence of galleries close to the root system. The damage of the larvae is typically summery, in the garden in July, August and September.

Also the adult can do damage, but of minor severity compared to the larva, they are often negligible problems, to the point of not justifying interventions. Beetles and oziorrinchi feed on shoots and young leaves, the attack can be recognized by the semicircular bites that can be distinguished at the edges of the affected leaves. The adults they attack instead mainly in spring.

The oziorrinco both in the larval and adult stages can attack many of our vegetables: from strawberries to cabbage, passing through peppers, lettuce, zucchini.

Root damaged plant.

Biological defense from oziorrinco

There defense from the larvae of oziorrinco it is similar to that against the beetle: in organic farming, insecticides are of little use against insects that live in the soil and we work in particular on prevention.

Prevent the settlement of eggs

This beetle must first be prevented: it must first and foremost keep the soil soft to discourage spawning, with frequent hoeing.

If digging or turning the compost you notice the larvae you have to collect and eliminate them, maybe we can move them instead of killing them. In family horticulture manual harvesting it always remains an excellent system of prevention and fight.

Freeing of hens in the freshly turned soil we can be sure that a good part of the larvae will be exterminated.

Insecticides and trapping

How insecticide neem oil could be used, with the limit that if the insect is in the ground it is not a very effective method.

Another biological defense strategy is a rudimentary trapping with strips of sticky paper that trap the beetle, but these traps are not selective and risk making innocent victims among the beneficial insects and are therefore not recommended.

Entomopathogenic nematodes

In the biological fight it is possible to decide to "deploy" a natural parasite of the oziorrinco, or the nematodeHeterorhabditis bacteriophora. This tiny worm enters the larva and parasitizes it from inside the body. The action of the nematodes leads the larvae to death in a few days.

There are also gods parasitic fungi of the oziorrinco and of the beetle, asBeauveria bassiana, which can help in exterminating them.

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