నైరూప్య

Citrus Leaf Miner ( Phyllocnistis citrella Stainton, Lepidptera: Gracillariidae): Biolology and Management : A Review

G Sarada  , K Gopal , T Gouri Sankar, L Mukunda Lakshmi, V Gopi , T Nagalakshmi , and KTV Ramana

The citrus leaf miner (CLM), Phyllocnistis citrella Stainton (Lepidptera: Gracillariidae), is a potentially serious pest of citrus (oranges, mandarins, lemons, limes, grapefruit and other varieties) and related Rutaceae (kumquat and calamondin) and ornamen tal plants almost worldwide. Several other hosts (Leguminaceae, Lauraceae, Oleaceae etc.) have been reported for CLM, however larvae do not complete their life cycle on these incompatible hosts. CLM is a widespread Asian species, first described from Calcu tta, India. It has been a widely distributed major pest in citrus - growing regions of Asia for many years. In the last 20 years, leaf miners have invaded most of the citrus - producing regions of the world, including the Mediterranean Basin and North, Central , and South America. The citrus leaf miner larvae only infest the younger, flushing foliage causing damage in nurseries and new plantings because of which the growth of young trees is retarded. The pest damage has shown a 50% increase in citrus canker in o rchards infested with CLM. The total generation period of CLM fluctuates between 13 - 52 days with 2 - 10 days for egg hatching, 5 - 20 days of larval period and 6 - 22 days of pupal development and a temperature of 30°C is optimal for CLM development. Depending o n foliage flushing cycles and weather conditions 6 to 13 generations per year can be expected. Peak pest activity was noticed during September to November months. In the management of this pest chemical control and b iological control are the two key tools . The complex of natural enemies attacking CLM include ants, spiders, small parasitic wasps and predators such as lacewings cau sing up to 90 percent mortality of larvae and pupae . Three of the most effective wasps are Ageniaspis citricola and Cirrospilus quadristriatus and Semiolacher petiolatus. The parasitisation rate was lower in June and July, being higher from August onwards and highest during September month. Unfortunately, the "best" natural enemy may not be found until all natural enemies and their biologies are known. Effective chemical control of CLM is difficult because the larva is protected by leaf cuticle and the pupa is protected by rolled leaf margins. However many pesticides belonging to different chemical groups were tested and found effec tive in its management. Several reports indicated that, the foliar application provides control for two weeks. Several bio - rational pesticides were tested and found useful in CLM management. The biology and management methods were reviewed in detail in thi s paper.