Larval development was significantly impaired by both metal and AMD treatments.

Similarly, weevil feeding and reproduction were reduced in the medium and high concentration AMD treatments.

Adult feeding in Neochetina was significantly reduced on plants exposed to both Cu and As while larval feeding was significantly reduced on plants exposed to Hg, Zn, As and Cu, with Cu causing the greatest effect. bruchi from each tub were dissected and the number of ovariole follicles was counted. After six weeks, the number of weevil larvae per plant, the number of adult survivors per plant, the number of adult feeding scars on leaves, and the number of larval mines per plant were recorded. Herein, the effect of eight different heavy metals common in AMD (arsenic (As), gold (Au), copper (Cu), iron (Fe), mercury (Hg), manganese (Mn), uranium (U) and zinc (Zn)), as well as three different simulated AMD concentration treatments (low, medium and high), on the performance of Neochetina weevils were investigated by releasing adults on plants growing in tubs and pools, three weeks after the addition of individual metal or AMD treatments. Nevertheless, little is known about the effect of heavy metals or AMD on Neochetina eichhorniae and Neochetina bruchi, which are the most widely established biocontrol agents on E. Metal concentration in plant shoots is known to affect insect herbivory. The prevalence of water hyacinth (Eichhornia crassipes) in South African water systems, despite the release of seven biocontrol agents since 1974, is often attributed to high levels of eutrophication. South Africa has one of the world's biggest gold mining regions with an associated problem of acid mine drainage (AMD), which increases the bioavailability of heavy metal contaminants in water.

Water hyacinth biocontrol agents