Search Results

You are looking at 1 - 2 of 2 items for

  • Author or Editor: Jodie D. Whitney x
Clear All Modify Search

Field experiments were conducted to investigate the effect of sprayer type, airflow rate, and nozzle output on deposition of active ingredient and mechanical harvesting of `Valencia' orange (Citrus sinensis). Fruit detachment force (FDF) and percentage of fruit removal (PFR) by trunk shaker were used as mechanical harvesting parameters. A PowerBlast sprayer discharging radially and a Titan sprayer discharging over the entire canopy were used. The spray mixture contained an abscission chemical (CMN-pyrazole), a surfactant (Kinetic) and a fluorescent tracer (Pyranine-10G). Deposition was determined at three different heights outside and inside of the canopy. With the PowerBlast, higher airflow and lower nozzle output reduced deposition of the active ingredient. The mean FDF of sprayed treatments was less than that of the non-sprayed control but the difference among the four spray treatments was not significant. The lower airflow rate with lower nozzle output had higher PFR than that of the control. With the Titan sprayer, the mean deposition at lower airflow was similar to or higher than the higher airflow. At higher airflow, the lower nozzle output gave higher mean deposition. The Titan sprayer treatments resulted in less FDF than the control. At both airflow rates, the FDF was less at lower nozzle output than at higher nozzle output. The PFR of these treatments were not different from that of control.

Full access


The effectiveness of microsprinkler irrigation for frost protection was examined during several cold nights in central Florida in 1981. Air temperatures ranged from 0 to 2.8°C warmer in the irrigated area above the spray zone than in the non-irrigated area, and were generally 0.5 to 1.5°C warmer. By irrigating under the tree, microsprinklers avoid some of the disadvantages associated with overhead sprinklers. Overhead sprinklers are not practical for freeze protection of large evergreen citrus trees because of limb breakage due to ice loading. During calm radiation cold nights, microsprinkler irrigation can provide some protection and is one alternative to burning petroleum products for citrus cold protection.

Open Access