cimici in casa

Bedbugs enter the house with the first cold weather: what they are, the remedies to keep them away and why they stink

When it comes to bedbugswe generally refer to those green and smelly insects that frequently enter the house in autumn, attracted by the heat of the rooms and the carbon dioxide emitted by the human body. The most easily visible species in this period are the two green bugs (Nezara viridula And Palomena prasina) and the Asian bedbug (Halyomorpha halys), That they are absolutely not dangerous for humans but they can represent a real scourge for many crops and mainly for fruit plants.

In reality, there are many bedbugs: these Heteroptera insects represent the entire family of Pentatomides (the name comes from the fact that the shape of their body resembles a pentagon), which counts for a lot 4000 species throughout the world, almost all of which feed on plant parts. They have colors ranging from bright green to brownish brown, while some species have metallic colors and one, the graphosome, is striped red and black. They should not be confused with bed bugs, which belong to the Cimicidae family and are parasites.

The green bug and the Asian bug: characteristics and habits

The mandible and maxilla of bedbugs are modified into two sharp stilettos suitable for sticking in a fruit or on the veins of a leaf so that it can suck the nutritious sap of the plant (stinging-sucking mouthparts). The holes produced cause damage to the plant tissues which cause the leaves to wilt and the fruit to deform. With the sting, a sort of “saliva” rich in digestive enzymes which contribute to the deterioration and blackening of the fruits.

There green bug Nezara viridula it is a cosmopolitan species, that is, it lives all over the world and with its stilettos it especially damages legumesespecially soy. It also attacks the tomatoes making them stained, misshapen and taste disgusting.

green bug Nezara viridula
Green bug of the species Nezara viridula. Credit: Katya from Moscow, Russia, CC BY–SA 2.0, via Wikimedia Commons

The green bug Palomena prasina it is decidedly less known worldwide, but is widespread in Italy and exploits fruit trees, shrubs and even cereal plants. AND very harmful to the hazelnut because its bites not only block the growth of young hazelnuts, but cause the so-called “bedbug” phenomenon which alters the flavor of the hazelnuts.

Green bug Palomena prasina
Green bug of the species Palomena prasina. Credit: Charles J. Sharp, CC BY–SA 4.0, via Wikimedia Commons

There Asian bedbug (Halyomorpha halys) is an invasive alien species and represents a real scourge for many crops. It is native to Asian countries (China, Korea, Japan and Taiwan) and has been accidentally transported among foodstuffs to the United States, Canada and many European countries. It has been present in Italy since 2012 and has found favorable conditions to spread especially in the Po Valley. It adapts well to anthropic environments and attacks many crops, including fruit trees such as apple, pear, cherry and peach trees, as well as vegetable plants. It is a species with high mobility: adults fly an average of 2 km per daybut they can travel up to 116 km. Its dispersal capabilities impose severe control measures, so much so that today in Australia and New Zealand, where the insect has not yet arrived, treatments are mandatory on goods coming from all European countries.

Asian bedbug Halyomorpha halys
Asian bedbug (Halyomorpha halys). Credit: Alpsdake, CC BY–SA 4.0, via Wikimedia Commons

Because bedbugs stink

A characteristic that makes bedbugs truly unmistakable is theacrid and persistent odor which emit if disturbed or crushed. The odorous substances are emitted by odorous glands and are effective repellents against enemies; they also make them disgusting to birds. So be careful when crushing them because the stench they release is really persistent. These unpleasant odors and flavors also contaminate the fruits and plants they feed on, making them inedible.

How to keep bedbugs away from homes and preserve crops: the remedies

To reduce the entry of bedbugs into your home it is advisable to:

  • apply mosquito nets on windows and anti-insect nets on chimneys and vents;
  • close any cracks in the wood or cracks in the walls that could serve as shelter;
  • remove bedbugs nestled in the house with a vacuum cleaner or steam cleaning tools;
  • spray on window sills natural repellents such as neem oil or eucalyptus or lavender essential oil.

Furthermore, new techniques are being tested to contain the damage caused by the Asian bug to crops, including:

  • positioning of anti-insect nets in the orchards with the arrival of spring:
  • experimental traps they use pheromones to attract and capture insects
  • use of hyperparasitic hymenoptera that prey on bedbug eggs.