A network that helps people worldwide obtain rapid advice and information on crop protection, including the identification and management of plant pests.
PestNet is a network that helps people worldwide obtain rapid advice and information on crop protection, including the identification and management of plant pests. It started in 1999. Anyone with an interest in plant protection is welcome to join. PestNet is free and is moderated, ensuring that messages are confined to plant protection.
Pests > Pests Entities > Weeds > Biological control > General – cautions & limitations, Palau & others
September 2002. A interesting discussion occurred when Palau asked about the identification of a mealybug. It was said that it was impossible to identify mealybugs from photos and they need to be sent to a specialist. All agreed to this. But there was also the suggestion that Palau should check to see if natural enemies are present, especially Cryptolaemus montrouzieri, which is an excellent predator.
However, members were reminded that if a photo was given at least it would have been possible to tell if the mealybig was Icerya. This was important as Rodolia is a better ladybird against this species than Cryptolaemus. Fluted scales (Icerya spp. often referred to as mealybugs) are only rarely utilised as hosts and the beetle cannot be used as a control agent for these scales.
Furthermore, members agreed that it was always advisable to be careful when considering predators that are not, or moderately, host specific for control of pests. Although in most cases mealybugs are still regarded as pests of agriculture and forestry, several may also have considerable potential as biocontrol agents for undesirable plants (i.e., weeds). A non-specific predator may, therefore, just as likely attack the beneficial mealybug as it would the pest mealybug.
As an example, the case of the release of Rodolia in Galapagos, to control Icerya purchasi was sited. Before any introduction of a biocontrol agent a specific study is required. In this case, it took 3 years’ research to ensure that would not attack any of the native (including endemic) scale insects, nor adversely affect the native predatory insects or birds.
And having the correct identification is a priority!