Nucleus Insects and Parasites

The hazel tree is a species which, due to its hardiness and adaptability, is found in the wild in various environments of hills and low mountains, but it is also cultivated for profit or private purposes and lends itself to biological agriculture.

Although it is elastic to accept different soil situations, the hazel plant can suffer in soils that are too asphyxiated and can sometimes be attacked by certain animal pests.

Let’s see what are the main insects and parasites that threaten the kernel, although serious damage is rare because it is not a particularly delicate species.

Contents [Ocultar]

  • Herophile nucleus

  • farmer

  • balanino

  • basic bug

  • Popilia japonica

  • Rodwood

  • mealybugs

  • Iphantria or American caterpillar

  • Hares and mini hares


Core Herophis

it’s a mite which particularly affects the central shoots, chosen for their overwintering sites. The presence of this small insect can be recognized by the size of the buds. The shoots attacked by the heriófido in fact take on an abnormal appearance, swell quickly and turn reddish, finally falling prematurely without being able to give life to the branches. Being a mite, sulfur-based treatments are effective, after carefully reading the instructions on the product packaging.


The adults of this insect appear around the in mid-may , laying their orange-white eggs on the bark of the trunk or the main branches. The larvae that hatch from the eggs dig tunnels in the wood, damaging the inner pots and thus causing yellowing of the foliage and early leaf drop. Branches affected by the agrilo show a characteristic spiral swelling. The severely affected plant has little chance of recovery and is more likely to die, so it is very important to identify the first symptoms and prune all affected parts of the orchard or hazel tree and thus free them from the presence of the farmer.


The adult of the balanino it is a brown insect, it has a long rostrum, that is to say a kind of beak thanks to which the female can pierce the shell of the hazelnuts as they ripen, and therefore still tender, to lay the eggs. From the egg comes a larva which begins to live at the expense of the seed, and from which it emerges only when it is ripe to fall in winter. Natural treatments based on the entomopathogenic fungus Beauveria bassiana carried out in autumn can make it possible to contain the attacks of this insect while remaining in organic methods.

basic bug

The kernel can be affected by several types of bugs: the green bug, the brown bug, and the dreaded Asian bug. The damage that bugs can cause are of several types: yes they bite the fruit in the early stages of their formation, they block their development, and the hazelnut falls to the ground early. On the contrary, if they perforate it later, when the seed is already partially formed, they cause what is called “bugging”, that is, the blackening of the pulp, whitish spots and, above all, a serious deterioration in the quality and worsening of the flavor of the hazelnuts, which makes them unusable.

Bedbugs are treated in organic farming with natural pyrethrum, azadirachtin or mineral oils.

Popilia japonica

The Popolia japonica is a bronze, metal and green collector from Japan, first found in Italy in 2014 in the Parque del Ticino. It is an extremely polyphagous species, it is found between June and September and among the species of cultivated and spontaneous plants that it attacks, devouring the leaves up to the ribs, there is also the hazel tree. The problem is that it has no natural predators in our regions, it is particularly widespread in Piedmont and Lombardy, where traps and treatments for entomoparasitic nematodes have been experimented with, research still in progress. In organic farming, it can also be used pyrethrum and kaolin the latter is a very fine white clay mineral that creates a patina on the leaves with a phago-deterrent effect (ie inhibits feeding) towards adult Popilia.


Wood rodents are Lepidoptera which, in the larval stage they dig tunnels on twigs and twigs, and their presence can be recognized by noting wood burns and droppings outside the penetration holes. To limit their presence, it is useful to place artificial nests to stimulate woodpeckers, birds that feed on these larvae. Direct ecological treatments are carried out with products based on Bacillus thuringiensis kurstaki.


They are small insects with rigid shields that stick to branches, bite them and suck their sap. If the scale insect infestation affects few plants, it is possible to brush the branches with metal tools, otherwise it is possible to spray them with macerations of ferns or treatments with mineral oils, which are authorized in organic farming even if they come from oil anyway.

Iphantria or American caterpillar

It is a defoliating moth that resembles the pine procession, but it is harmless to humans and animals and, although it is polyphagous, it does not attack conifers. Ifantria is widespread especially in northern Italy and here normally the fairly cold winters are able to contain its presence by killing many overwintering forms, but the milder temperatures that have been recorded in recent years have not probably not helped as limiting factors. The damage caused by the larvae of the American caterpillar is skeletonization leaves , of which they only keep the ribs, leaving all the canvas and excrement on them. Ifanthria also affects hazel, but its favorite species seem to be mulberry and American maple, so consider spy plants for this parasite. To control it, the affected branches full of larvae must be eliminated and destroyed and treated with Bacillus thuringiensis kurstaki, preferably at night and in time because this ecological product is more effective on young larvae.

Free and mini-free

Newly planted seedlings in certain areas are at risk of being burned by hares or mini-hares, attracted by the young shoots. Sufficient protection is provided by net rings temporarily placed around all young stone specimens.

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