Experimental Site
In 1998–1999, three field trials were conducted in a
12-year-old commercial planting of mixed orange varieties
grafted to Swingle citrumelo rootstock, located
near Fort Pierce, Florida. The grove was planted as two
row beds at a setting pattern of 3.0 3 7.6 m. Soil type
was a Pineda sand (alfisols) with a low to moderate
organic content and a pH of 6.9. The grove wasequipped with low-volume under-tree micro-jet sprinkler
irrigation. At the time of the tests, infestations of
D. abbreviatus and Pachnaeus litus (German) were
evident in the grove.
Eighty plots were arranged on double-row beds separated
by a drainage ditch 7.6 m in width. Each plot
was composed of 6 trees in row with a total of 12
trees/plot (;93 m2). Only the 4 center trees per plot
were sampled, although the whole plot received treatment.
A 5-tree buffer was maintained at the end of
each planting bed. Plots were arranged in a completely
randomized design with eight experimental treatments
and 10 replications. In tests 2 and 3, where
fewer than eight treatments were applied, unused
plots were still treated with nematodes.