Halyomorpha halys, or the infamous and much-feared Brown Marmorated Stink Bug (BMSB). We have grown accustomed to recognizing this insect, characterized by its multiple shades of brown and light bands on its antennae. For a few years now, it has appeared alongside the more common green stink bug, well-known for its unpleasant odor. Let’s discover more about this troublesome pest.
What is the Brown Marmorated Stink Bug and what are its characteristics?
Originally from China and a permanent presence in US orchards for a decade, this unwelcome guest was first reported in Italy in 2012, in the Modena area. In recent years, it has spread from Emilia-Romagna to Veneto, Lombardy, Trentino, and Friuli-Venezia Giulia, earning a reputation as the new scourge of Northern Italian agriculture. To understand why, we must keep in mind several key behavioral traits:
- In the spring-summer period, it causes damage to numerous plant species, both cultivated and wild;
- In cold months, it overwinter in large colonies inside our homes or shelters where, protected from the cold, it enters a state of hibernation;
- Adult specimens can live up to one year;
- In each generation, the female lays an average of 250 eggs, which develop into new adults in just over a month.
Given these factors, and considering that there can be up to four generations in a single year, it is clear that we are facing a full-scale invasion.
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What damage does the Brown Marmorated Stink Bug cause to agriculture?
The stink bug feeds by piercing the fruit. This process creates:
- Necrotic areas on the outer surface;
- Rot in the internal pulp;
- Premature fruit drop;
- Seed loss;
- Potential transmission of phytopathogens, affecting both the quantity and quality of agricultural production.
In fruit farming, attacked species include apples, peaches, nectarines, plums, cherries, apricots, kiwis, and pears. Losses can reach 100% of the harvest. Vegetables such as zucchini, eggplant, lettuce, tomatoes, and peppers are not immune either. Furthermore, the first cases have been detected in cereals and even grapes. The sheer variety of affected crops in regions with a high concentration of farms is causing massive damage totaling hundreds of millions of euros. The production system risks failing to meet market demands in terms of quality and quantity, leading to social risks as the industry employs tens of thousands of permanent and seasonal workers.
How do you eliminate Brown Marmorated Stink Bugs?
The most common defenses used so far include pheromone traps and full-coverage anti-insect netting over rows. While theoretically very effective, netting requires significant investment, and even a few specimens that manage to penetrate accidentally can cause major damage. Chemical defense does not seem to help much either. Because stink bugs prefer the underside of leaves or crevices in the plant, they are difficult to reach. Furthermore, being highly mobile, they can re-colonize a treated environment in a very short time.
Currently, the scarcity of new registered chemical formulations and increasingly stringent legislation are pushing farmers to test the “collateral effectiveness” of products used against other pests. This emergency situation, however, risks creating an indiscriminate increase in chemical use, causing further harm to the environment and human health. This approach makes environments hostile for pollinating insects, which are vital for the vegetative cycle, and reduces the few predators capable of feeding on the stink bug. With a view to introducing specific predators, the effectiveness of the Samurai Wasp—the natural predator of the BMSB—is currently being tested. However, introducing a new species into an already fragile environment risks altering the balance between predators and prey, with unpredictable effects on native species.
How to solve the problem of the Brown Marmorated Stink Bug?
It is clear that coordination between all involved parties—from farmers to competent authorities—is indispensable. It is possible to start curbing the problem with targeted interventions:
- Conducting widespread monitoring at the perimeter of plots, where the bug resides before entering the crops;
- Developing a precise and comprehensive defense program, whether chemical or physical;
- Encouraging scientific research to identify new, targeted, and effective molecules and methodologies that respect the environment and support precision agriculture.
The true resource for this shift in direction is science. We at Nanomnia are aware of this reality and work to ensure that both new and existing molecules are more effective and selective, applicable precisely only in areas infested by insects or pathogens. Only in this way will it be possible to save raw materials, respect beneficial species, and, above all, reduce the excess of products that currently pollute soil and groundwater.