BP Singh

Principles and Concepts of Plant Quarantine 41infested/infected/ contaminated planting material from one countryto another, as of their own they are not capable of travelling longdistances. Thus, the accelerated pace of exchange of germplasmthroughout the world these days has exposed the world to greaterrisk of introducing exotic pests and- pathogens in 'clean areas'.There are several such cases reported in literature. This would beevident from the following few examples. European com borer(Ostrinia nubilalis) entered USA from Europe and became moreprolific and polyphagus than in Europe resulting in losses ofmillions of dollars. The introduction of the late blight pathogen(Phytophthora infestans) of potato into Ireland from Centrai Americaabout middle of 19th Century, resulted in almost completedevastation of potato crop and the result was mass migration ofIrish people to all parts of the world. In 1870 Ceylon (now SriLanka) was one of the foremost coffee producing countries in theworld with an industry based on Coffea arabica, an EthIopianspecies, recognis,ed for quality. In 1875, coffee rust appeared inCeylon and devastated the plantations. Production dropped from400 million pounds in 1870 to 5 million pounds by 1889 forciI,lgthe cultivators to abandon coffee plantation and take to teaplantations. It is believed that the rust got introduced from EastAfrica. In 1908, cotton production in Mississippi (USA) was1,800,000 pounds. Four years later, this production was reducedto one-third due to the inroads made by cotton boll weevil(Anthonomus grandis) which moved into USA from Mexico. In,1960, it was estimated that this pest was costing the USA anaverage of $ 375 million per year. Similarly, stem and bulbnematode (Ditylenchus dipsaci) severely attacked red clover insouthern part of Sweden for many years, so lucerne was suggestedas an alternate crop because though a host, it was not attacked bythe nematode. But recently there are reports that this also is beingattacked by this nematode~doubtlessly the 'lucerne race' of D.dipsaci got introduced into that area from somewhere through seedas this nematode is also transmitted through seed. This examplealso illustrates the fact that introduction of a 'race' may be asdisastrous as introducing a new species or an exotic pest in acountry /region. These are a few significant examples of lossesarising from the introduction of a disease or a pest into a country,which could have been avoided had there been an effectivequarantine'in those days.