At this time of year, autumn, the Asian stink bug (Halyomorpha halys), completely harmless to humans and domestic animals, can create quite a few nuisances and inconveniences in our homes: adults nest in warm, sunny places, seeking shelter in homes to spend the winter and if disturbed they let themselves fall to the ground, pretending to be dead or, in the worst case scenario, they emit their “stink” to defend themselves. A completely different question, however, is their impact on crops: damage to orchards,olive tree and soy can be very large. For example, the attack of bugs on tomatoes can cause a reduction in volume, tissue damage and a decrease in antioxidant power. In the United States, where the first specimens of the Asian stink bug arrived in Pennsylvania in 1996, 37 million dollars in damage was caused to the apple industry in 2010 alone. In Italy, in 2019 they were estimated approximately 14,500,000 Euros of damage in Lombardy alone at the expense of periculture and apple growing. 2025 was characterized by a resurgence of the invasion compared to the previous two years, so much so that farmers’ trade organizations such as CIA and Coldiretti reported a drop of up to 60% in production of pears in the Ferrara area and devastating impacts also on other crops. How do you fight bedbugs in agriculture? Current protocols for the control of the Asian stink bug combine physical methods (such as pheromone nets and traps), chemical treatments (phytosanitary) anduse of parasitoids (the introduction of natural enemies such as the Samurai Vespa).
Which plants does it attack and how does the damaging effect of the sting work
According to some researchers, when the invading insect colonizes new areas, it initially distributes itself in urban areas where it comes from transported accidentally with goods and vehicles, and where he can easily find shelter and food. It is sometimes nicknamed “hitchhiking insect“, precisely because its spread is favored by means of transport. Once it has multiplied from urban environments, it begins to move very quickly to the suburbs and agricultural areas and at that point the damage begins.
The Asian bug is, so to speak, an insect with a “good mouth”: it is a polyphagous species and it feeds on over 300 different plant essences between spontaneous and cultivated. In our latitudes, in natural environments, it mostly prefers elderberry, dog rose, hawthornthe mulberry, the hazelnut and hops. Among the cultivated plants he chooses fruit plants such as apple treebut, I peach and olive treeherbaceous plants such as corn, soy and sunflower, vegetables such as tomato, pepper, aubergine and, for some years, also attacks the screw. In the United States, in California, almond orchards are also damaged. Insect bites cause damage to the husk and cause the formation of necrotic tissues on the shell: in general the affected fruits become deformed and blacken.
Both adults and juvenile stages (nymphs) feed on lymph pricking plant tissues with the sharp stylets of their stinging, sucking mouthparts. They are so sharp that they are able to pierce the surface even of leathery fruits, like hazelnuts.
Having penetrated the tissues, they inject a particular saliva which is the most harmful component for the fruit. The salivary glands of the bedbug produce two types of saliva: one more watery and one more sticky consistency which hardens in contact with air. Watery saliva contains digestive enzymes such as amylase which degrade plant tissues and fruit pulp, while the more viscous saliva has a different chemical composition, hardens when emitted and creates a sort of protective case around the stylets while they suck the predigested plant food. When the insect moves, it is possible to notice some sort of hole around the hole made on the fruit empty micro-tube. Furthermore, the emission of sticky saliva causes a chemical reaction in the fruits that produce defense substances.
A group of researchers from a Hungarian Agricultural Faculty analyzed the attack of the sui bug tomatoesthrough the execution of a Tomography and a series of chemical analyzes on the vegetables. The investigation found that the tomatoes showed reduction in volume, tissue damage which spreads from the surface towards the inside based on the penetration of saliva, a marked decrease in their antioxidant power.
On theolive tree the attack of the Asian bed bug determines early fall of olives (phenomenon called fruit drop), reduction of their size and increase in phenolic substances which modify their flavour.
A study conducted on vineyards of Veneto both with red and white grapes such as Cabernet, Merlot, Pinot grigio, has shown that bedbug infestation is quite late in the autumn season, the red berry varieties are more attacked than the white berry ones and that the innermost portions of the vineyard are more protected from attacks than the external edges. Furthermore, the affected grapes rot and are attacked much more easily by gray mold, a grape pathogenic fungus (Botrytis cinerea)
How to fight bugs in agriculture: defense systems
In the agricultural field they exist and must be applied precisely protocols for prevention and control of the Asian bug. At the moment, they do not completely resolve the situation, but they mitigate the consequences of these invasions.
In particular, we recommend:
- Pheromone traps placed in orchards which attract bugs in aggregate form so as to eliminate them en masse;
- Anti-insect nets to be placed on orchards;
- Treatments with authorized plant protection products (neonicotinoids and pyrethrins). Generally they prove to be of little use because there are few effective substances and their not very persistent action;
- Use of parasitoidsnatural enemies of bedbugs that attack their eggs. Among these the most famous is the Vespa samurai (Trissolcus japonicus), but other wasp species are also being tested such as Trissolucus semistriatus And Telenomus chloropus.
