Ants

General  

• Hymenoptera insects grouping together about 14,000 species with or without a stinger, distributed in several globally distributed genera. More than 285 species are known in France.
• They are social insects living in colonies.
• Omnivorous eating behavior, feeding on aphid honeydew, various insects and small invertebrates, plant substances and parts of plants including fruits, etc.
• Ants show different behaviors on plants: breeding aphids, predation of phytophagous pests, parasitism, etc.
• The workers cause the damage observed on plants. Occasionally serious on eggplant, especially in certain crops under cover.
• Sensitive crops :
• Organs attacked  : neck, stem close to the ground, fruits.

• Symptoms :
  • more or less deep degradation of the cortex on sections of stems close to the ground, and at the neck.
  • Browning vascular tisus put in the air and therefore more protected.
  • Poor growth, loss of vigor of plants.
  • Leaf wilt, plant dieback.
  • Depreciation of fruit quality, even loss of harvest of affected plants.

• Signs  : Presence of small earthy conical domes at the base of the eggplant stems.
• Possible confusion :

Biology

• Development cycle : it mainly includes 4 stages in ants and lasts an average of 5 to 10 weeks.
  • The queen lays small, smooth eggs that evolve into larvae in about ten days.
  • The larvae are medium to large in size; their body is made up of several small rings. Four to five larval stages may follow one another over a period of 2 to 4 weeks.
  • Subsequently, we find the nymphs which are the same size as the ants, but they are folded on themselves and are sometimes wrapped in a cocoon. It takes a week to 1 month for the nymph to become an adult.
  • As soon as they are born, adult ants show different activities depending on their caste.

Protection

• These pests do not normally require special interventions in crops.