CONTROL OF ASIAN CITRUS PSYLLID AND CITRUS LEAFMINER WITH FOLIAR APPLICATIONS OF INSECTICIDES IN ORANGES DURING SUMMER, 2008

ACP vectors the bacterium Candidatus Liberibacter asiaticus causal organism of greening or Huanglongbing disease of citrus. Feeding damage from CLM facilitate the spread of citrus canker caused by Xanthomonas axonopodis pv. citri. Biological and chemical means of control and their compatibility is important in reducing the populations of both pests and for integrated pest management in Florida citrus. The experimental block at the Southwest Florida Research and Education Center, Immokalee, Florida consisted of 13-yr-old sweet orange ‘Valencia’ trees planted on double-row raised beds at a density of 132 trees/acre. Trees were irrigated by micro-sprinklers and subjected to conventional cultural practices. Swale sides of the trees were pruned manually to induce new flush and encourage ACP infestation. Seven treatments and an untreated check were randomly distributed across 4 replicates in 17 rows that included a buffer row after every treated row. Each replicate contained 8 plots of 5 plants each distributed across 8 treated rows. Treatments were applied on 22 May 2008 using a Durand Wayland 3P-10C-32 air blast speed sprayer with an array of six # 5 T-Jet stainless steel cone nozzles per side operating at a pressure of 200 psi delivering 150 gpa at a tractor speed of 1.5 mph. However, treatments were washed out due to a sever thunderstorm immediately after applications and were reapplied on 23 May. The low rate treatment of Micromite was planned for two applications and the second application was made on 12 Jun. Post treatment evaluations for adults were made on 28 May, 4, 11, 18, and 26 Jun, and 3 Jul. Evaluations for immatures were made through 11 Jun except low rate of Micromite and Danitol which were evaluated through 3 Jul. Three central trees in each plot were sampled. A “tap” sample made by striking with the hand a randomly chosen branch 3 times and counting adult ACPs falling on a clipboard covered with an 8 1⁄2 × 11 inch white paper was used to estimate ACP adults. One tap sample on the first sampling, two on the second and third, and four on the fourth, fifth and sixth sampling dates were conducted per tree adjusted due to the low numbers of adults observed particularly on the treated trees. Three flushes suitable for ACP oviposition and nymphal development were tagged on each tree on 20 May. Eight of the nine tagged flushes were examined post treatment for presence or absence of ACP nymphs, and to record the oldest nymphal instar on each flush. These same eight flushes were also examined to count CLM larvae on five leaves per flush. Data were subjected to ANOVA to evaluate treatment effects on ACP and CLM and means separated using LSD (P = 0.05).