Phytophagous bugs

True bugs

Biting sucking insects, bedbugs are mostly considered harmful, because of their diet. Indeed, the saliva injected into the plant with their rostrum (figure 1), kills and dissolves the cells around the bite, the liquid obtained then being aspirated. When the insect is present en masse on the plant, or attacks young tissues (buds, growing leaves), the multiplication of bites leads to rapid necrosis of plant tissues (figure 2). The species that can cause damage in the vineyard are not specific to the vine, but can develop there when the weed vegetation has been destroyed, or by the presence of relay plants.

Among the bugs that can be harmful to the vineyard, we can mention the following species:

Miridae

• Apolygus spinolae (Meyer-Dur, 1841), green vine bug (syn. Lygus (Neolygus) spinolai Wagner 1961, figure 3) is responsible for risetta (Italy) or leaf curling. This bug, which is very mobile in hot weather, stings young buds and clusters when they are rough. The leaves are dotted with brown and have holes in them. This bug mainly causes damage in Switzerland and Italy.
• Capsodes sulcatus Fieber, 1861 (grapevine grisette) (formerly Calocoris or Lopus sulcatus ) (figure 4). It is in the pupal stage that this species lives exclusively at the expense of flower buds by feeding on the flower peduncle or on the bud and then the berry does not develop. If many grains are affected it is part of the bunch which dries up and falls off. After mating and laying eggs in the folds of the bark of the vine, the adult continues its activity in the surrounding vegetation. This insect is however not very widespread in the vines.
• Closterotomus fulvomaculatus (De Geer, 1773), the hop bug, can attack vines, the flowers and berries of which it causes to abort by its bites, inducing a loss of yield.

In this family, there are also predatory species of mites and insect pests.

Lygaeidae

• Nysius senecionis (Schilling, 1829) (figure 5) small bug 4-5 mm long, is sometimes observed in the vineyard in Languedoc Roussillon in case of lack of food in the surrounding vegetation following mowing, but does little damage despite a some pullulation. These are rare very localized and temporary attacks, in summer, which can cause the leaves to dry out. It is a species which lives mainly on asteraceae and which lays eggs on flowers. It is the adult who hibernates.

Pentatomidae

• Eurydema oleracea (Linnaeus 1758), green cabbage bug or vegetable bug, which lives mainly on crucifers (figure 6), and which can be found in the vineyard, where these plants are present (interrang). It can attack the young leaves of the vine.
• Halyomorpha halys (Stål, 1855), the devilish bug or marbled bug that has recently been introduced to France. It is an arboreal species that attacks fruits. For the moment, this species is under surveillance in the Alsatian vineyard.
• Palomena prasina wood bug (Linnaeus 1761), green (Figure 1). It does mostly damage to apples and pears, but does little to attack vines in the south of France, such as the nearby species P. viridissima (Poda, 1761).
• Nezara viridula (Linnaeus 1758), a green punctate bug or soybean green bug, which damages tomatoes and other fruits, is not yet harmful to vines, but has already been observed on grapes.

Biological cycle

Heterometabolous insects, bedbugs develop in 5 larval stages before sexual maturity (Figure 7) which occurs without pupation. Depending on the species, bedbugs hibernate at various stages of their growth (egg, pupa or adult). The shape of the eggs, their location and their arrangement are generally characteristic of the different genera. These eggs are laid singly or in groups, they can be deposited on the surface of plants (figure 8) or inserted inside a stem or under the bark.

Biological regulation

Bedbugs in the adult stage or in the last larval stages can be parasitized by tachinous flies, for example Gymnosoma rotundatum (Linnaeus, 1758) (figure 9) or Trichopoda pennipes Fabricius 1781, a species introduced in Europe. These auxiliaries attack more particularly the Pentatomidae. The females lay eggs on the bedbugs and the first larval stages of the flies enter the host and develop to its detriment. the Scelioninae (Chalcidian Hymenoptera, Platigastridae) are oophagous parasitoids of the Pentatomidae (photo). The birds and spiders are predators of herbivorous bugs.

Bibliography:

Alford DV (2007) Pests of Fruit Crops: A Color Handbook. Elsevier, 461p

Arzone A, Vidano C, Alma A (1990) Vineyard agro-system Heteroptera in the Mediterranean Region. Scopolia, suppl. 1, 101-107 ( lien )

Caccia R, Remund U, Boller E, Baillod M (1988) The green vine , bug Lygus spinolaï (Meyer-Duer), extension and importance in Switzerland. Swiss Journal of Viticulture Arboriculture Horticulture, 20 (2) 109-116.

Galet P (1982) Diseases and parasites of the vine. Volume II, animal parasites.

Classification : Animalia, Arthropoda, Insecta, Hemiptera, Heteroptera

English name : true bugs