POPULATION-LEVELS OF LEPTODICTYA-TABIDA (HEMIPTERA, TINGIDAE) IN FLORIDA SUGARCANE

Three sugarcane (Saccharum spp.) fields in southern Florida were sampl ed to assess population densities of the sugarcane lace bug (Leptodict ya tabida Herrich-Schaeffer) on leaves during 1990 - 1992. The study b egan several months after the bug was first discovered in Florida. A m ean of 6.3 (SEM=0.51) bugs (all life stages) per leaf was observed ove r the entire study. Average densities per field per sample date ranged up to 74 bugs (all stages) per leaf. The bug was present from late sp ring through winter but exhibited a propensity for 2 annual peaks in d ensity, one during late spring/early summer before summer rains and on e during the fall after summer rains. Bug populations were very low fr om late March to May. A general decline in densities of the bug occurr ed during the study. No parasites, predators or pathogens of the bug w ere observed. In a laboratory trial, adults and nymphs survived 3-h ex posures to 0 degrees and -5 degrees C, indicating short periods of col d weather may have little impact on population levels of the bug. Amon g 14 sugarcane varieties, 'CP73-1547' was relatively resistant to the bug while 'CP81-1254' was relatively susceptible based on bug densitie s per leaf.