A butterfly as pests causing concern in Europe is the Geranium Bronze (Cacyreus Marshalli) which is in the family Lycaenidae. Originally from South Africa, where its larval food plant was the geranium or pelargonium, somehow it was introduced into Europe, where it is wreaking havoc amongst growers of its food plants. It is an unusual and attractive butterfly, so its presence won’t break the hearts of many lepidopterists unless they happen to grow geraniums or pelargoniums.
Butterflies and moths can be both pets and instrumental in the control of pests. Mostly, they’re pests causing untold amounts of damage to agriculture. The most notorious is, of course, the Cabbage White, which is a general name given to many similar species of Pierids, including the small white (Pieris rapae), the large white (Pieris brassicae), and the green-veined or mustard white (Pieris napi). Of these three, only the first two are pest species.
Two months have been instrumental in the control of rogue plant species. These are the Crimson Speckled Footman (Utetheisa Pulchella), which was used in Australia to bring the prickly pear cactus under control. The other is the Cinnabar moth, Tyria jacobaeae, which feeds, among other things, on ragwort, a poisonous plant found in cattle fields. These represent a serious threat to any animal that eats them. However, every year the caterpillars strip the foliage, usually so severely that the plant can’t seed
Perhaps the most serious lepidopterous agricultural pest is the gypsy moth (Porthetria dispar), which causes untold economic damage to forested areas. It was introduced to the U.S. from Europe in 1869, when some were sent to an amateur entomologist in Medford, Massachusetts. Some of these were accidentally allowed to reach the wild, from where they started to colonize the New England states.
The moth quickly established itself, as there were no natural parasites to limit its spread. This, combined with the fact that each female lays up to a thousand eggs made it a very successful immigrant. Another reason why it has managed to spread throughout the United States is that its larvae will eat many hundreds of different plants, and if its preferred choices are not available, it will eat almost anything.
Several different methods have been tried to wipe out this pest, but none of them has been anything more than a passing success. In the 1960s, one of its natural parasites, a braconid wasp (Rogas indescretus), was released in yet another attempt. Unfortunately, though, it is not limited to the gypsy moth and has been found parasitizing a related species. This cross-over from pests to the indigenous fauna is a serious problem and needs to be addressed whenever a non-active parasite or predator is introduced to a new locality.
Other control methods tried include pesticides, diseases, pheromone traps, and encouraging natural predators. Of these, only the traps are ecologically sound, with no impact on the species. Controlling pests without damaging the local habitat is a real problem sometimes releasing infertile male’s works, and other times parasitic nematode worms will drastically reduce numbers.
The answer probably lies with more research, but that suffers from the opposite problem: survival in a harsh economic climate severely limits the number of research scientists.
Also Read: Butterfly Classification How They’re Named
