A comprehensive analysis of the Asiatic citrus canker eradication programme in São Paulo state,Brazil, from 1999 to 2009

Asiatic citrus canker (ACC), caused by Xanthomonas citri subsp. citri, has been controlled by exclusion and eradication measures in São Paulo state (SP), Brazil, since it was first detected in 1957. Several protocols of eradication have been used since then, but the protocol applied from 1999 to 2009 was the most successful and well documented of these. During that time, if the incidence of trees with symptoms in a citrus block was ≤0.5%, the infected trees and the symptomless trees within a 30 m radius were removed. However, if the incidence was >0.5%, the entire block was eliminated. Subsequently, inspections were carried out to monitor the affected blocks during quarantine. Although this protocol did not eliminate the disease from SP, it suppressed the incidence of affected blocks to very low annual levels (<0.20%) for a decade. Of over 5000 foci detected, 65.1% were eliminated by removing the block, either when disease was first detected (47.8%) or at a subsequent detection (17.3%), and 28.4% were eradicated by removing trees within a 30 m radius. The latter method was not an effective stand‐alone measure for ACC eradication and the 0.5% threshold was the key factor in suppression of disease statewide. Currently, a re‐emergence of ACC is occurring in SP. The information presented here will aid the establishment of protocols for the eradication of ACC in other citrus‐growing areas with low incidence of the disease or at risk of pathogen introduction.     

(2E,4Z )-Decadienoic acid and (2E,4Z,7Z )-decatrienoic acid,two herbicidal metabolites from Streptomyces viridochromogenes Tü 6105

Two fatty acids, (2E,4Z)-decadienoic acid and (2E,4Z,7Z)-decatrienoic acid, the latter being described for the first time as a natural product, were detected in the culture filtrate of Streptomyces viridochromogenes Tü 6105 by HPLC-diode array screening, purified by chromatographic methods and structurally elucidated by NMR techniques. Both metabolites show strong herbicidal activity against Lemna minor and Lepidium sativum. The herbicidal activities of the isolated compounds were compared with those of similar fatty acids and derivatives. © 1999 Society of Chemical Industry     

The metabolism of the pyrethroid insecticide (±)-α-cyano-3-phenoxybenzyl 2,2,3,3-tetramethyl-cyclopropanecarboxylate,WL 41706, in the rat

The metabolism of the pyrethroid insecticide α-cyano-3-phenoxybenzyl 2,2,3,3-tetramethylcyclopropanecarboxylate (WL 41706) has been studied in rats using two forms of ¹⁴C-labelling (benzyl- and cyclopropyl-). Excretion of benzyl^?14C was rapid, 57% of the administered dose being eliminated in the urine 48 h after treatment and 40% in the faeces. No significant sex difference was observed. The amount of radioactivity excreted via expired gases was 0.005% of the administered dose and less than 1.5% of the dose remained in the animals 8 days after treatment. The mean percentage recovery of administered dose was 104% for male rats and 97% for female rats. Urinary and faecal metabolites from these rats, and from rats dosed similarly with [cyclopropyl^?14C]-WL 41706 were studied. The rapid metabolism of WL 41706 is due to efficient cleavage of the ester bond by rats in vivo to afford 2,2,3,3-tetramethylcyclopropanecarboxylic acid (partly as glucuronide) and the 3-phenoxybenzyl moiety. Before this cleavage occurs, however, about half of the intake suffers aryl hydroxylation giving the α-cyano-3-(4-hydroxyphenoxy)benzyl ester, part of which is excreted in the bile as a conjugate(s) and part of which is cleaved and eliminated as the O-sulphate of 3-(4-hydroxyphenoxy)benzoic acid and the glucuronide of 2,2,3,3-tetramethylcyclopropanecarboxylic acid. A minor amount of hydroxylation occurs at a trans-methyl group on the cyclopropane acid moiety. The metabolism of WL 41706 by rat liver occurs mainly in the microsomes and mainly via oxidative processes.