An insidious enemy for the plants of our garden and for the cultivation of ornamental and fruit plants: the oziorrinco.
This parasite belongs to the beetle family and is able to cause enormous damage to vegetable gardens and gardens as it feeds on roots and leaves.
Particularly attacks so-called ornamental plants, such as cyclamens and azaleas, but some species of weevil they are also attracted by olive trees and vines from the garden.
The larvae live in the soil for a very long period ranging from one to four years during which they feed on the bulbs, roots and lower parts of the plants. Once the root is affected, the plant is often destined to die.
Instead, adult individuals prefer to attack the leaves: characteristics to recognize a plant attacked by weevil adult are the classic crescent-shaped lesions.
The oziorrinco feeds mainly at night: starting from sunset it comes out of its underground burrow and goes up the plant stem passing the night to feed on the youngest and tender leaves. At dawn the insect retires underground.
The constant attack of this annoying beetle leads the plant to die slowly: both the attacks on the roots and on the leaves cause serious irreversible suffering. In particular with regard to the leaves the progressive lack of surface in gratitude to activate photosynthesis is often lethal.
It is therefore important to identify immediately the presence of oziorrinco larvae: the period of greatest diffusion of the beetle is during the warm season, from May to October. It is particularly widespread in areas from the center to the south of Italy.
Recognize the oziorrinco
In addition to the symptoms found on the plant, it is important to identify insect colonies to organize a targeted struggle that can solve the problem.
The oziorrinco eggs are oval in shape and change color over time: from white they become yellow and then dark gray. They are laid by adult females in June: each female is able to deposit hundreds of eggs in the ground, in a period of life that lasts about two or three months.
The oziorrinco larvae have an arched body without legs about one centimeter long. They are white with a red head that varies from red to brown. The larval stage lasts a long time and causes the individual to pass through three different evolutions before becoming a pupa and then an adult. It is in this period that the oziorrinco undermines the health of the plant starting from the root.
Adult individuals have different colors depending on the species from intense brown to glossy black, some individuals may present metallic nuances or punctuation.
The body is an oval body with a length varying from five to ten millimeters.
They walk slowly but are able to easily ascend the stems of all the plants, even using the stakes for young plants.
How to fight the oziorrinco
The ideal months to fight and exterminate the oziorrinco range from September or October, a period in which the insect is in the larval stage. It is indeed very difficult to focus the struggle on adult individuals, both for their propensity to nightlife and for an ever more evident ability to resist common pesticides.
However, due to force majeure, it is possible for ornamental plants to use pyrethrum-based preparations capable of killing insects by ingestion or contact. There are also specific soil disinfectants that can destroy eggs and larvae.
However, the greatest risks must be considered with respect to the benefits that operations of this type involve: in the case of plants destined for human consumption it is absolutely not recommended to resort to these methods.
A useful device to limit the damage caused by the adult individual in the trees consists in covering the trunk of the tree with a band made of a material similar to glass wool. This would prevent the insects from ascending by blocking their passage since this species of beetle has no wings.
Other practical alternatives are to cover a small piece of stem with a strip of fly adhesive paper, so as to imprison the passing adult individuals.
Even shaking the plants could be a method to catch unwanted guests: in fact, as a reaction to the danger, these insects let themselves go as a dead weight defense, interrupting any activity. With a cloth under the tree it is therefore possible to trap some specimens. These operations must be repeated for several consecutive days and always in the evening night time slots, since, we remember, the oziorrinco is a nocturnal animal.
Even lighting the leaves can be an effective method to "scare" the oziorrinco.
Like all methods of this type, in addition to constancy, it is necessary to estimate a targeted attack also on larvae. It would make no sense to think about eliminating the problem by forgetting its source ...
Organic fight with oziorrinco
To combat the infesting populations of oziorrinco in an effective and lasting way, the most effective remedies remain those based on biological control.
There are no other insects capable of attacking the oziorrinco, both because of its size and because of the hard shell that protects it: but there are parasites that can feed on its larvae.
Several companies distribute larvae of Heterorhabditis bacteriophora, a "parasite of the parasite" able to feed on the oziorrinco larvae.
These larvae are absolutely harmless for plants and humans and are sold in an inert material. It is necessary to dilute with water and pour directly to the base of the plant attached, when the soil conditions allow a good soil moisture.
It is important to perform these operations in the early morning or late afternoon, to avoid the evaporation of the liquid and the death of the nematodes. The ideal temperature to prepare this defense is that which goes from 15 to 30 degrees: it is therefore preferable to carry out these operations in the pre-summer period or before the arrival of autumn, remembering to always maintain an adequate soil moisture. It should unfortunately be remembered that this form of defense turns out to be effective if applied on sandy or pasty soils, while it does not bring appreciable results on clayey soils.