Dr. Tim Grout
Dr. Sean Moore, Dr. Aruna Manrakhan, Prof. Martin Hill,
This programme includes important cosmetic and production pests such as citrus thrips, Scirtothrips aurantii, bollworm, Helicoverpa armigera, red scale, Aonidiella aurantii and citrus psylla, Trioza erytreae. There is a continuous search for more IPM-compatible means for controlling these pests, such as mating disruption for red scale and entomopathogenic fungi and botanicals for some of the other pests. Research on the Asian citrus psylla, Diaphorina citri, has also been initiated in collaboration with Mauritius, where both the African and Asian species occur. This is in proactive anticipation of the movement of the Asian species down the African continent. Research on citrus psylla primarily focuses on alternative control strategies to systemic organophosphates.
Although mealybugs are considered key pests from a cosmetic and production viewpoint, their phytosanitary threat is most serious. Research to identify the important natural enemies of indigenous species is being conducted and entomopathogenic fungi are being developed for control of mealybug and other pests. GRAS fumigants for postharvest disinfestation of fruit are also being investigated. Other pests which have phytosanitary implications for certain markets, and which are being investigated within this programme, are carob moth and Fullers rose beetle. An extensive study on the pest status of carob moth and development of pre- and postharvest management strategies has just been completed.
This programme also covers research on leafhoppers, woolly whitefly, leafrollers, citrus flower moth, citrus leafminer, fruit piercing moth and all pest mites. The potential for disrupting the biocontrol of pests and potential pests is investigated in this programme. Standard bioassay techniques have been developed for five indicator species: (1) Aphytis coheni; (2) Chilocorus nigritus; (3) Euseius citri or E. addoensis; (4) Trichogrammatoidea cryptophlebiae; (5) Coccidoxenoides perminutus. A database of non-target effects for these natural enemies to most chemicals used in citrus orchards has been developed. Classical biological control of the woolly whitefly is being pursued with the importation, release and now confirmed establishment of the parasitoid, Cales noacki. Management of hitchhiking oribatidulid mites through postharvest fumigation is also being investigated and their control in the orchard.
Adult male red scale Aonidiella aurantii emerging
backwards from under scale cover.
Damage caused by Helicoverpa armigera on the left and
Ascotis selenaria reciprocaria on the right
Different life stages of the predatory bug