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The effect of herbivory by Gratiana boliviana Spaeth (Coleoptera: Chrysomelidae) on the invasive, tropical soda apple (TSA) (Solanum viarum Dunal, Solanaceae), was investigated using exclusion methods and by monitoring the density of G. boliviana and the weed at four locations over a period of 40 months. TSA plants protected by insecticide were taller, wider, and had greater canopy cover that unprotected plants, and plants in closed cages were taller and wider than those in open cages. Survival of plants was higher in plots protected with insecticide than in unprotected plots in both years of a 2-year study. In the population dynamics study, the initial density of TSA was 4-5 times higher at one of the locations than at the other three sites, but within 3 years, TSA density at the high density site had declined by 90%. At the three sites which initially had a low abundance of TSA, density remained low throughout the study. The intrinsic rate of increase of G. boliviana varied between -3.9 and 4.5, but over the 3-year study, was not different from zero, indicating a stable population. The intrinsic rate of increase was lower than zero for the period from October to January, and greater than zero during the January to April period. In the periods from April to July and July to October, the rate of increase was not different from zero. The implications of these results for biological control of TSA in Florida are discussed. [ABSTRACT FROM AUTHOR]

Schinus terebinthifolius Raddi (Sapindales: Anacardiaceae) is a non-native perennial woody plant that is one of the most invasive weeds in Florida, Hawaii, and more recently California and Texas. This plant was introduced into Florida from South America as a landscape ornamental in the late 19th century, eventually escaped cultivation, and now dominates entire ecosystems in south-central Florida. Recent DNA studies have confirmed two separate introductions of S. terebinthifolius in Florida, and there is evidence of hybridization. A thrips, Pseudophilothrips ichini si. (Hood) (Thysanoptera: Phlaeothripidae),is commonly found attacking shoots and flowers of S. terebinthifolus in Brazil. Immatures and occasionally adults form large aggregations on young terminal growth (stems and leaves) of the plant. Feeding damage by P. ichini sI. frequently kills new shoots, which reduces vigor and restricts growth of S. terebinthifolius. Greenhouse and laboratory host range tests with 46 plant species in 18 families and 10 orders were conducted in Paraná, Brazil, and Florida. Results of no-choice, paired-choice, and multiple-choice tests indicated that P. ichini sI. is capable of reproducing only on S. terebinthifolius and possibly Schinus nwlle L., an ornamental introduced into California from Peru that has escaped cultivation and is considered invasive. Our results showed that P. ichini si. posed minimal risk to mature S. molle plants or the Florida native Metopium toxiferum L. Krug and Urb. In May 2007, the federal interagency Technical Advisory Group for Biological Control Agents of Weeds (TAG) concluded P. ichini s.l. was sufficiently host specific to recommend its release from quarantine. [ABSTRACT FROM AUTHOR]

The biology of Episimus utilis Zimmerman, a natural enemy of Brazilian peppertree, Schinus terebinthifolius Raddi, was investigated in a quarantine laboratory as part of a classical biological control program against this invasive weed in Florida. Adults lived on average 6.8 ± 0.8 d, and a generation was completed in 43.6 d at a temperature of 22.0°C and a photoperiod of 12:12 (L:D) h. Peak egg production occurred 2 d after females eclosed from the pupal stage. Females deposited a maximum of 172 eggs, with an average daily maximum of 13.6 eggs. The durations of the egg, larval, and pupal stages were 5.9, 23.7 (five instars), and 12.0 d, respectively. Stage-specific life tables were constructed to calculate basic population statistics. Under laboratory conditions where predation and food supply were not limiting factors, a population of E. utilis was capable of multiplying its population by 1.17 times per day, and a doubling of the population would occur every 4.4 d. To date, 10 consecutive generations of E. utilis have been produced on potted Brazil peppertree plants in the laboratory. The potential effectiveness of F. uulis as a biological control agent of Brazilian peppertree in Florida was examined using Goeden's revision of the Harris scoring system. [ABSTRACT FROM AUTHOR]