How to Manage Pests

UC Pest Management Guidelines


Leaf and Fruit Drop Control Following an Oil Spray

(Reviewed 9/08, updated 9/08)

In this Guideline:

Variety Amount to use

Calculate impact of pesticide on air quality
Bee precaution pesticide ratings
Not all registered pesticides are listed. Always read label of product being used.
CAUTION: Avoid 2,4-D spray drift to susceptible plants, which include cotton, grapes, roses, beans, peas, alfalfa, lettuce, ornamentals, and all broadleaf species. 2,4-D has a 12 hour restricted entry interval.
A. ALL 2.2 ml 2,4-D isopropyl ester formulation/gal oil
  COMMENTS: Restricted entry interval (REI): 12 hours. Used in pesticide oil sprays to counteract leaf drop and fruit drop caused by the oil. Gives some degree of preharvest fruit drop control but because of the long time span between most pesticide oil sprays and the onset of mature fruit drop, the 2,4-D/oil spray may not give adequate mature fruit drop control, especially if the per acre 2,4-D dosage is less than 24 grams acid equivalent (60 ml of a formulation containing 3.34 or 3.36 lb of 2,4-D/gal). Under these conditions, an aqueous 2,4-D preharvest spray may be needed. If the 2,4-D/oil spray occurs within 3–4 months of the fruit drop period, and if the per acre dosage was at least 24 grams, no additional 2,4-D should be applied. If the fruit drop period will occur 4–6 months after the 2,4-D/oil spray was applied, apply an aqueous spray at about 50% of recommended rates for preharvest fruit drop control. If the fruit drop period will occur more than 6 months after the 2,4-D/oil spray, apply full rates recommended for preharvest fruit drop control. Apply to trees 6 years and older. Do not apply within 7 days of harvest.



[UC Peer Reviewed]

UC IPM Pest Management Guidelines: Citrus
UC ANR Publication 3441

Plant Growth Regulators

  • C. J. Lovatt, Botany and Plant Sciences, UC Riverside
Acknowledgment for contributions to Plant Growth Regulators:
  • C. W. Coggins, Jr., Botany and Plant Sciences, UC Riverside

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