LIBRO-CONGRESO-CITRUS

S20P09
Dissipation and residue of 2,4-D in citrus fruits
Chen W. J. 1 , Su X. S. 2 , Zhao Q. Y. 1 , and Jiao B. N. 1
1 Citrus Research Institute, Chinese Academy of Agricultural Sciences, China; and 2 School of Chemistry and Chemical Engineering,
Southwest University, China. bljiao@tom.com
The dissipation and residue of 2,4-D in citrus fruits under field conditions were studied. The field trial was
conducted in three provinces of China. An analytical method using QuEChERS cleanup and ultra performance
liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) was successfully applied to analyze 2,4-D
in citrus fruits. The recoveries were in the range of 85.0-%-107.8-% at three spike levels with relative standard
deviations of 1.0-%-4.6-%. The results showed that the dissipation kinetics of 2,4-D in citrus fruits did not
follow with the first-degree reaction pattern. The degradation rate of 2,4-D in citrus at 65 days (2010) and 75
days (2011) were 42.7-77.3% and 31.2-59.1%. The terminal residues in pulp peel and whole fruits were all
bellow the maximum residue limit (MRL) value set by European Union (EU) (1 mg/kg). Two supervised trials
on the post-harvest use of 2,4-D on orange and ‘Ponkan’ mandarin were also conducted. The residues of 2,4-
D at day 0 in orange samples treated with the 200 mg ai/L 2,4-D solution and in ‘Ponkan’ samples treated with
the 250 mg ai/L 2,4-D solution were 0.122 mg/kg and 0.265 mg/kg, respectively, both bellow the MRL set
by EU. The degradation rate of 2,4-D in orange and ‘Ponkan’ fruit after 96 days and 93 days were 55.6% and
76.5%. Hence it was safe for the use of 2,4-D and the results could give a reference for MRL setting of 2,4-D
in citrus fruits in China.
S20P10
Effect of pesticide spray volumes and doses on the production of marketable lemons in Tucumán,
Argentina
Salas López H. 1 , Mansilla C. 2 , Figueroa D. 1 , Carrizo B. 1 , Rojas A. 1 , Campos A. 1 , and Goane L. 1
1 Estación Experimental Agroindustrial Obispo Colombres (EEAOC), Fruticultura, Argentina; and 2 CITRUSVIL, Argentina.
hsalas@eeaoc.org.ar
Current management of lemon trees includes different pesticide volumes and doses. Field trials were
conducted in lemon orchards located in two climatically and ecologically different regions throughout
three years to evaluate the impact of three spray volumes (10000, 5000 and 2000 L/ha) and three doses of
pesticides (high, medium and low) on lemon fruit health. The highest pesticide dose consisted of 15 kg/ha
of a commercial product of copper hydroxide (53.8%), 100 L/ha of mineral oil and 2 L/ha of a commercial
product of abamectin (1.8%); medium and lowest doses had the same components, but different quantities:
the medium 7.5 kg, 50 L and 1 L, respectively, and the lowest 3 kg, 20 L and 0.4 L per hectare respectively.
Trials were conducted in a randomized complete block design with four replicates. Healthy fruit percentage
was estimated at harvest from approximately 2.000 fruits per plot. Damaged fruits were separately analyzed
to discriminate the main cause for rejection: wind, pests or diseases. Independently of doses, healthy fruit
proportion was significantly higher in plots sprayed with high and medium pesticide volume. Such treatments
were more efficient for controlling pests (mealybugs, mites and thrips) mainly, although they resulted in a
higher proportion of fruit damaged by wind. The study demonstrated that a reduction of pesticide spray
volume (to 5000 L/ha) and doses is possible without affecting fruit quality.
XII INTERNATIONAL CITRUS CONGRESS 2012 - 349
S20