Antagonism and symbiotic control

Insects interfere with human activities in several ways. They can cause losses in agriculture production by feeding on crops or on stored agricultural products. Others can be vectors of pathogenic microorganisms that cause severe diseases in plants, animals and humans. Two striking examples among the many deleterious insect vectors already described are mosquitoes of the genus Anopheles and planthoppers the first transmitting the malaria parasites to humans. Planthoppers transmit during feeding cell wall-less bacteria of the genus ‘Candidatus Phytoplasma’ that, by infecting phloematic cells, cause diseases in several plants. Phytoplasmas infect several fruit plants including grapevine, in which cause diseases called grape yellows. A grape yellow with increasing incidence in the European vineyards is Bois Noir (BN), caused by ‘Ca. Phytoplasma solani’, a cell wall-less bacterium belonging to the Stolbur group (16Sr XII). ‘Ca. Phytoplasma solani’ is spread throughout the vineyards by the insect vector Hyalesthes obsoletus (Hemiptera, Cixiidae).