Biological control and citrus: a long time fruitful story

From the earliest days, agriculture has been plague by pests. Growers have to deal with outbreaks of insects,weeds, and plant pathogens. There has been a continual increase in arthropod pest species invading citrusover the past century. Citrus systems are replete with mite and insect pests, both in terms of their abundanceand diversity. Growers rely on several approaches to pest control, including mechanical, cultural, chemicaland biological methods. In this conference I outline the practice of biological control. Biological control refers to the use of living organisms, or products derived from living organisms, such astoxins, for control of insect pests, weeds and plant diseasesBiological control is considered by many to be the best alternative to pesticides. Biological control is efficient,safe for humans and the environment, and in most cases cheaper than chemical control. Natural enemiesexert a significant, continuous and naturally level of pest population regulation in natural or managedecosystems. Biological control also refers to the deliberate introduction of specific natural enemies to controlspecific populations of weeds, plant diseases or insect pests. Such an approach may involve the discoveryand release into a crop of natural enemies, and in some instances their production and commercialization asbiological control agents. At least 7,000 introductions of natural enemies involving almost 2,700 species havebeen made worldwide. The most widely used species have been introduced into more than 50 countries. In augmentative biological control, more than 170 species of natural enemies are produced and sold, butsome 30 species make up more than 90% of the market worldwide. Biological control has a long traditionof success in citrus. In 1868, the cottony-cushion scale was found on acacia in California. Ten years later thecitrus industry was at the verge of collapse because of the scale. Natural enemies were sought in the nativehome of the pest, southern Austr