There are species differences regarding the developmental toxicity of procymidone (Sumilex®), a fungicide with a weak anti-androgenic activity. To clarify key factors of these species differences, pharmacokinetic and excretion studies in rats, rabbits, and monkeys were conducted using 14C-labeled procymidone. One hydroxylated metabolite of procymidone (Hydroxylated-PCM: very weak anti-androgen) was found to exist longer and at a much higher concentration in rat plasma than in rabbit and monkey plasma. In rabbits and monkeys, Hydroxylated-PCM was transformed into a glucuronic acid conjugate (Hydroxylated-PCM-glucuronide: non-anti-androgen) and rapidly excreted into urine as a major metabolite. On the other hand, it was a minor metabolite in rat urine. The results of biliary excretion studies indicated that these species differences were caused by the species differences in the biliary excretion of Hydroxylated-PCM-glucuronide; this variation in biliary excretion rate was concluded to be related to species differences in developmental toxicity.

Our knowledge of the ecological impact of insecticides on aquatic organisms is lacking at a community level because it requires high research skills, due to the complexity of community interactions. Here, the aquatic community's response to the residues of two systemic insecticides, imidacloprid and fipronil, with different physicochemical properties was monitored for three years. In this study, four key points are considered for evaluating the ecological impact of the insecticides in relation to biodiversity conservation. These are as follows: (1) environmental fates as explained by their different physicochemical properties, (2) life cycles and habitats of each taxonomic and functional group, (3) indirect effects through the food chain, and (4) long-term field monitoring over the course of a year.

1 Laboratory of Reproductive Biology, Department of Animal Biology, Faculty of Science and Technology, University Cheikh Anta Diop, P.O. Box-5005, Dakar Fann, Senegal 2 Functional and Evolutionary Entomology, Gembloux Agro-Bio Tech, University of Liege, Passage des Deportes 2, P.O. Box-5030 Gembloux, Belgium 3 Bio-Industries/C.W.B.I., Gembloux Agro-Bio Tech, University of Liege, Passage des Deportes 2, P.O. Box B-5030 Gembloux, Belgium

To evaluate the influence of growing conditions on the pesticide residue in lettuce heads, we investigated the residue levels in open field and greenhouse conditions. A clear difference between the two growing conditions was observed for dinotefuran applied to the planting hole; the residue levels in the lettuce heads from the greenhouses were almost as high as those in the field samples. In contrast, no clear difference between the two growing conditions was observed for the other three pesticides applied to the foliage. The size reduction process for sample preparation also affected the variation in this residue data; the ranges between two size-reduced samples of dinotefuran were narrower than the values of the other three pesticides. Those results are part of the complex factors affecting the pesticide residue levels in lettuce heads in different growing conditions and with different types of application.

The solubilization of hydrophobic organic pollutants from soil is important for the phytoremediation of contaminated soil. In this study, we used perylene as a model pollutant to evaluate the abilities of 11 organic acids to solubilize hydrophobic compounds from soil. Oxalic acid and citric acid showed high solubilization abilities, and when added to soil, they enhanced perylene uptake into Cucurbita pepo, likely owing to the chelating ability of these acids.

To find strigolactone (SL) biosynthesis inhibitors, we screened the azole-containing chemicals that reduce the level of 2′-epi-5-deoxystrigol (epi-5DS) in rice. As a result of the screening, tebuconazole, a known fungicide targeting ergosterol biosynthesis, was selected as a potent SL biosynthesis inhibitor. A structure-activity relationship study of tebuconazole was carried out to discover more potent SL biosynthesis inhibitors. By evaluating the inhibitory activity on epi-5DS biosynthesis, we found that 2-(2-chlorophenyl)-4-(4-chlorophenyl)-1-(1H-1,2,4-triazol-1-yl)butan-2-ol (4b) and 4-(4-chlorophenyl)-2-(4-phenoxyphenyl)-1-(1H-1,2,4-triazol-1-yl)butan-2-ol (4e) showed potent ability to reduce epi-5DS biosynthesis.

Penthiopyrad is a novel fungicide belonging to the carboxamide group. This compound was discovered by Mitsui Chemicals Agro, Inc., and launched in Japan in 2010 under the trade name Affet® SC in the fruit and the vegetable market and in 2009 under the name Gaia® WDG in the turf market. Penthiopyrad has broad antifungal spectrum of not only Basidiomycetes but also Ascomycetes and Deuteromycetes, and as a result, the broad antifungal spectrum contributes to its excellent ability to control various kinds of diseases on important crops in one treatment.

Magnaporthe oryzae (Anamorph: Pyricularia oryzae), the causal agent of rice blast disease, is the major pathogen that reduces the yield of rice worldwide. Melanin biosynthesis inhibitors (MBIs) and strobilurins (QoIs) are common fungicides used to control the disease. One hundred and three M. oryzae isolates from different rice-production areas in Taiwan were evaluated for their molecular phylogeny and sensitivity to MBI and QoI fungicides. Molecular phylogenetic analysis showed that all M. oryzae isolates could be classified into nine genetic groups (A–I) based on the DNA polymorphism amplified by CNS1/MP primers. Predominant ones are groups A (72 isolates) and B (15 isolates). Fungicide tests showed that M. oryzae isolates were sensitive to MBIs (carpropamid and tricyclazole) and less sensitive to QoIs (kresoxim-methyl and azoxystrobin). Amplifying the cytochrome b (cyt b) gene revealed that isolates with low sensitivity to QoIs did not correspond with mutation at codon 129 or 143 in the cyt b gene.

We describe the purification, cDNA cloning, and characterization of a defensin, AFP1, in Brassica juncea, which shares 100% amino acid sequence identity with Raphanus sativus defensin (Rs-AFP1) and has a high antifungal activity against Magnaporthe oryzae. The recombinant AFP1 synthesized in Escherichia coli showed thermostability and antifungal activity against a broad spectrum of rice pathogenic fungi. The changes of a negative to positive charge at the surface of AFP1 derived by amino acid substitutions showed more enhanced antifungal activities than the wild-type AFP1.

A simple and rapid method for the measurement of a neonicotinoid pesticide, nitenpyram, and its metabolites, CPMA and CPMF, was investigated. The three compounds were determined individually and simultaneously by simple ultrasonic extraction followed by hydrophilic interaction liquid chromatography-tandem mass spectrometry (HILIC-MS/MS). Good chromatograms were obtained using a non-modified silica gel column. The calibration curves were straight (R2>0.999) for each compound; they were 0.002–2 mg/kg for 5 g of agricultural product sample with limits of detection (S/N=3) of 0.24–0.36 µg/kg (nitenpyram), 0.12–0.19 µg/kg (CPMA), and 0.13–0.18 µg/kg (CPMF). Good recoveries were obtained for sweet pepper, mandarin orange, onion, and brown rice (93.0–106.6% in recovery). For contaminated samples, data by the presented method agreed well with nitenpyram data by HPLC-UV and the total of CPMA and CPMF by derivatization followed by gas chromatography-flame thermionic detection.