Epitrix hirtipennis (Melsheimer) 

Tobacco flea beetle

General

• Widespread insects belonging to the order Coleoptera and the family Chrysomelidae: subfamily Alticianae.
• Likely to attack in addition to eggplant: tomatoes, peppers, potatoes and some wild nightshades (especially morels and datura).
• In France, the flea beetle Epitrix hirtipennis, a pest native to North and Central America, has been emerging since 2016 in the Bouches du Rhône and is gradually spreading. It has nothing to do with the criciferous flea beetle and especially cabbage.
• Observed in the open, as if under shelters.
• Other species are reported on nightshades *: E. fasciata (Blatchey) - E. cucumeris (Harris) - Psylliodes brettinghami (Baley)

* Note that two new American flea beetles of the genus Epitrix have recently been introduced in Europe (Portugal and Spain) developing on potatoes: Epitrix similaris parasitizing tubers on which the larvae leave a sinuous network of scars; Epitrix cucumeris devouring the leaves giving them a lace appearance.

• Organs attacked : leaves, flowers, fruits
• Symptoms :
  • Leaves with small, regular (a few millimeters) and rather rounded blade perforations; they are linked to the parasitism of adult insects which regularly graze and devour the upper and lower surfaces of the leaf blade (figure).
  • Leaves more or less riddled, sometimes taking the appearance of a lace and can dry out (figures) .
  • Grazed flower petals (figure).
  • Small lesions on young fruits at the time of fruit set which, as they grow, become lignified and discolored on the periphery. Their incidence becomes more important as the fruit develops, which can lead to their downgrading.
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• Signs  : Presence of adult insects on the leaves and sometimes the flowers of plants (figures).
• Possible confusion : In the past, the different species of flea beetles of the genus Epitrix have been confused with those of the genus  Leptophysa .

 Biology

• Development cycle :
  • Eggs laid by females on the ground at the foot of plants, isolated or in small groups.
  • Whitish larvae developing in the soil at root level: three successive larval stages.
  • Adults of E. hirtipennis are in  brown color and up to 2 mm long. They overwinter in soil or plant debris. They resume activity in the spring in May-June, then the population increases sharply during the summer following several successive generations. In the fall, the population decreases sharply in October-November.

 Protection

• Weed the crop and its surroundings.
• Produce the seedlings in an nursery insect-proof .
• Check the sanitary quality of the plants before and during their introduction into the crop or shelter. For the flea beetle, the mesh of the net must be less than 1mm. Be careful, this type of net modifies the climate of the shelters with the consequence of altering pollination more or less. The introduction of bumblebee hives may be necessary. In addition, also beware of attacks by Botrytis cinerea, the reduction of populations of large auxiliary insects such as adults of ladybirds, hoverflies, lacewings, etc. prevented from entering through the fine mesh of the nets.
• Install  canvases insect-proof in the nursery, on the rows in the open field when planting, and at the openings of shelters when weather conditions allow.
• Mulch the culture to limit the emergence of adults.
• Reason the  chemical protection that is possible for phytophagous beetles use. Remember to respect the conditions of use of phytosanitary products and do not forget that they can greatly hinder integrated protection strategies against other eggplant pests. They are therefore to be used in a limited and localized manner on plants.
• Treat plants before uprooting in the presence of high pest populations