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Hyadaphis foeniculi
Fennel Aphid
Hyadaphis foeniculi is a cosmopolitan aphid species and major pest of fennel (Foeniculum vulgare), native to Mediterranean regions and introduced to Brazil and other areas. Laboratory studies demonstrate strict thermal requirements: nymph development occurs only between 15-30°C, with 3°C and 33°C lethal. The species exhibits four nymphal instars with temperature-dependent development rates, completing the nymphal stage in 5 days at 30°C to 19 days at 15°C. Winged adults reproduce parthenogenetically, forming colonies inside fennel flowers during hot periods. The aphid vectors at least 12 plant viruses and produces honeydew that facilitates sooty mold growth, compounding crop damage.