also been collected from leaves, stems and seeds. Biochemistry Rhizoglyphus secrete an alarm pheromone from opisthonotal glands. This pheromone has neryl-formate as its main component and citral and α-acaridial as minor components. Its secretion triggers escape behaviour in other mites and it may be involved in mite defense against predators. Citral and α-acaridial also have antifungal activity. These mites also have a range of cuticular chemicals. Hexyl rhizoglyphinate is another antifungal, while the roles of other chemicals remain unknown. Pest status As noted previously, Rhizoglyphus feed on a range of plants. Infested bulbs may rot and fail to produce new growth, or new growth may be discoloured, stunted and distorted. In tulips, Rhizoglyphus may enter prematurely opened buds and cause bud necrosis. Bulbs that are damaged or infested with Fusarium fungus are more vulnerable to attack. Due to their pest status, these mites are classified as quarantine species by many countries such as Australia and New Zealand. Control measures Rough handling of bulbs should be avoided as this can cause damage that allows Rhizoglyphus to enter. Keeping bulbs dry also generally prevents them from being attacked, since the mites cannot withstand drought. A range of pesticides have been used, but Rhizoglyphus are resistant to a number of pesticides and there is concern about pesticides affecting non-target species. There has been research on biological control of this genus of mites. Most of this has involved predatory mites, but entomopathogenic nematodes have also been considered. Species Rhizoglyphus actinidia Zhang, in Zhang, Jiang & Zeng 1994 Rhizoglyphus algericus Fain, 1988 Rhizoglyphus algidus Berlese, 1920 Rhizoglyphus alliensis Nesbitt, 1988 Rhizoglyphus allii Bu & Wang, 1995 Rhizoglyphus balmensis Fain, 1988 Rhizoglyphus costarricensis Bonilla, Ochoa & Aguilar, 1990 Rhizoglyphus echinopus (Fumouze & Robin, 1868) Rhizoglyphus eutarsus Berlese, 1920 Rhizoglyphus frickorum Nesbitt, 1988 Rhizoglyphus fumouzi Nesbitt, 1993 Rhizoglyphus globosus Berlese, 1920 Rhizoglyphus longispinosus Ho & Chen, 2001 Rhizoglyphus narcissi Lin & Ding, 1990 Rhizoglyphus occidentalis (Sevastianov & Tamam-Nasem-Marros, 1993) Rhizoglyphus occurrens Berlese, 1920 Rhizoglyphus robini Claparédè, 1869 Rhizoglyphus robustus Nesbitt, 1988 Rhizoglyphus sportilionis Lombardini, 1947 Rhizoglyphus termitum Womersley, 1941 Rhizoglyphus trouessarti Berlese, 1897 Rhizoglyphus tsutienensis Ho & Chen, 2000 References External links Acaridae