© Benaki Phytopathological Institute
Hellenic Plant Protection Journal
9:
51-59, 2016
DOI 10.1515/hppj-2016-0006
1
Center for Environmental Research and Studies, Jazan
University, Jazan, Saudi Arabia
2
Department of Biology, Faculty of Science, Jazan Uni-
versity, Jazan, Saudi Arabia
3
Department of Environment, Faculty of Marine Sci-
ence and Environment, Hodeidah University, Yemen
* Corresponding author:
The principal active component in qat
leaves is cathinone (
(S)-
2-Amino-1-phenyl-1-
propanone, C
9
H
13
NO), which is known for its
mild stimulatory effects; recently, synthetic
cathinones have been sold worldwide under
the name “bath salts” (Katz
et al.,
2014; Daba
et al.,
2011). Qat is moderately used as a tra-
ditional medicine by indigenous people of
East Africa, but neither the plant itself nor its
isolated active ingredients have been wide-
ly recognised for their therapeutic use (EM-
CDDA, 2016). According to the literature, qat-
chewing is linked to adverse health effects,
such as liver toxicity, an increased risk of car-
diovascular events, reproductive problems,
psychosis, and periodontal problems (Date
et al.,
2004; Al-Hebshi and Skaug, 2005).
Qat has been reviewed by the WHO Ex-
pert Committee on Drug Dependence
(ECDD) on a number of occasions.
Catha edu-
lis
remains outside international control, al-
though cathinone and cathine, which arises
from the metabolism of cathinone in the ma-
ture plant, have been listed in the 1971 UN
Convention under Schedules I and III, respec-
tively, since the early 1980s. Qat is controlled
in a number of European countries including
Belgium, Denmark, Germany, Greece, France,
Ireland, Italy, Latvia, Lithuania, Poland, Slo-
Persistence of imidacloprid, acetamiprid and methomyl in qat
leaves
A.J. Al-Rajab
1,*
, A.M. Alhababy
2,3
and T. Alfaifi
2
Summary
Qat leaves are chewed on a daily basis by approximately 10 million inhabitants of different
countries. This study investigated the persistence of three insecticides most used in qat production,
imidacloprid, acetamiprid and methomyl. These chemicals were applied separately on plots of ten qat
trees each at the recommended application rates. Samples of qat leaves were collected separately at
time 0 (1 h post-treatment) and 1, 3, 7, 12, 19, 26 and 37 days after application. The residues of the inves-
tigated pesticides were extracted and then quantified by liquid chromatography (LC-MS/MS). The half-
lives of imidacloprid, acetamiprid and methomyl were 12.2, 11.7, and 5.1 days, respectively. Overall, our
findings showed that imidacloprid and acetamiprid were more persistent than methomyl in qat leaves.
Taking into account the maximum residue limits (MRL) in lettuce, due to lack of MRL in qat leaves, the
residue concentrations were below MRL for imidacloprid 7 days after application, and 1 day after ap-
plication for acetamiprid and methomyl.
Additional keywords
:
chat, degradation, half-life, insecticide, khat, qat
Introduction
Qat (
Catha edulis
, Forsk) is a perennial shrub,
also known by the common names khat or
chat, cultivated only in specific regions of a
few countries encompassing the Red Sea:
Yemen, southwestern Saudi Arabia, Ethi-
opia, Eritrea, Djibouti, Kenya, and Somalia
(Alvi
et al
., 2014; Gebissa, 2010). The fresh qat
leaves are chewed for 3–6 hours on a daily
basis (usually in the afternoon) by around
10 million inhabitants of these regions; this
habit is referred to locally as “takhzeen al-
qat”
(Hassan
et al
., 2013; Al-Motarreb
et al
.,
2010). Moreover, the habit of qat chewing
has recently been introduced to other Af-
rican countries, such as Uganda, Burundi,
and Rwanda (Numan, 2012), as well as to the
United States, Great Britain, and Western
Europe by the Eastern African and Yemeni
communities of these countries (Bongard
et
al.,
2015; Al-Motarreb
et al.,
2010).
