Brown marmorated stink bug (Halyomorpha halys)

The brown marmorated stink bug (Halyomorpha halys), also known as Asian stinkbug, is a polyphagous insect capable of feeding on over 300 species of plants from different families, eating fruits, leaves and sprouts, which makes the management of this pest particularly challenging.

Native to West Asia, this biting-sucking insect has already arrived in Europe and is becoming a pest of global importance for many agricultural crops. In Portugal, we are not free from its invasion. Although it is considered that this pest is installed in a region/ country when a colony is identified, the fact that in 2019 an individual was intercepted in the Pombal region, on a kiwi production property, is not to be overlooked. According to DGAV - Directorate-General for Food and Veterinary Medicine, he hitched a ride from a farm implement imported from Italy, which is precisely the European country with the most economic losses related to the marmorated stink bug.

Before Europe, the Asian bug was accidentally introduced in the USA, in 2001, and in Chile in 2017. On the European continent, it first arrived in Switzerland, in 2004. It was from these points of introduction that it expanded to other parts of the world. In 2020, its presence was confirmed in 22 countries and, in Europe, it is already spreading rapidly – the most serious case is that of Italy, especially in the North, where it is already considered one of the main pests of fruit orchards, having led to the collapse of existing Integrated Pest Management programs.

In addition to the destruction of vegetables and fruit trees, another major problem of this insect is its discreet behavior, which allows it to go unnoticed in the transportation of any type of merchandise, such as suitcases or farm implements, thus facilitating its spreading and threatening international trade and the economy of the invaded countries. In the USA alone, it has already caused losses of millions of dollars in horticultural crops and, in Europe, the losses are increasingly high in orchards of various fruits, including hazels. On arrival in a new country, it is able to spend the first years without being noticed, but, in reality, it is quite active, reproducing and settling in until reaching a considerable sizes and populations.

Since Halyomorpha halys populations closest to Portugal are established in the Catalonia region (Spain), it is expected that, if the pest is installed in our country, agricultural crops such as tomatoes, corn, pear, kiwi, grape, orange and others may be severely affected, and there is still no effective form of control. The losses in the production of these foods can reach 90%, since the insect, when causing scars, depressions, discolorations, deformations or falling of the produce, makes its commercialization unfeasible.

Drosophila suzukii

Commonly known as spotted wing drosophila, Drosophila suzukii is the only species of drosophila capable of causing considerable damage to healthy fruits. Its main hosts are various fruits, especially small ones and with fine cuticles, such as strawberries, blueberries, blackberries, raspberries, Arbutus unedo berries, elderberries and cherries, and may also appear in grapes, figs, persimmons, kiwis, plums, peaches and apricots.

Infestation begins with the perforation of the fruit surface, where females of this species lay their eggs. The larvae that feed on the fruit pulp aggravate the process. A few days later, infested fruits may shrink or decompose. In addition to primary infection, secondary infections by fungi or bacteria accelerate destruction on a large scale, and all production can easily be lost.

The wide range of possible hosts is one of the difficulties in the fight against this species that came from Japan and arrived in Europe in 2008. Currently, the most efficient method to detect the presence of the pest at the site and to monitor its evolution is to capture adults using traps, similar to those used in mass capture described below.