Seasonal dynamics, dispersion, sequential sampling plans and treatment thresholds for the citrus leafminer, Phyllocnistis citrella Stainton (Lepidoptera: Gracillariidae), in a mature lemon block in coastal New South Wales, Australia

摘要: Studies of citrus leafminer in a coastal orchard NSW, Australia indicated that an increase abundance to about one mine per flush was followed during the midseason by rapid population related percentage leaves infested within flushes and number mines leaf. The fits frequency distributions Iwao's patchiness regression populations were highly contagious initially, as exponent k negative binomial distribution increased with increasing density, approached random. Concurrently, coefficient variation (which strongly proportion un-infested flushes) decreased unity reached zero fell further increased. Both numerative sequential sampling plans developed using decision threshold based on 1.2 flush. plan closely fitting model functional relationship between mean density flushes. Functional relationships parameters determined from Taylor's power law equally satisfactory, also fitted well, but Poisson did not. three best models equivalent 50% infested. From practical point view, transition 25% infestation through is so it may be prudent take action when level reached; otherwise, passed before crop checked again. For valuable nursery stock should detected spring, advisable apply prophylactic treatment starts.