Parasites & Diseases
Special care must be taken to check the freshly cut food plants for the presence of spiders, which should not be introduced into the breeding cages. One can wash the fresh food in a shower before it is placed in the cages.
During the winter aphids can cause problems, as either aphid eggs or small nymphs develop and breed quickly in the warm climate and absence of predators, when food plants are brought indoors. The excrements produced by the aphids (honeydew) make cleaning the cages more difficult and encourages the development of mould which especially harms more fragile species. Introducing ladybirds (Coccinella septempunctata) as predators for the biological control of the aphids has proven unsuitable because the ladybirds would not only eat the aphids but newly hatched phasmids as well (BRAGG, 1991).
The eggs of several species are often affected by mould. E.g. in Extatosoma tiaratum and Acrophylla wuelfingi mould develops only a few days after the eggs are laid. The mould readily grows on the surface of the egg-capsule of these species but does not seem to have an apparent adverse effect on the development of the embryo. Otherwise, eggs which go mouldy are often those which contain dead embryos or were already damaged before incubation.