Residues in beeswax: a health risk for the consumer of honey and beeswax ?

A scenario analysis in regard to the risk of chronic exposure of consumers to residues through the consumption of contaminated honey and beeswax was conducted. Twenty-two plant protection products and veterinary substances of which residues have already been detected in beeswax in Europe were selected. The potential chronic exposure was assessed by applying a worst-case scenario based on the addition of a “maximum” daily intake through the consumption of honey and beeswax to the theoretical maximum daily intake through other foodstuffs. For each residue, the total exposure was finally compared to the acceptable daily intake. It is concluded that the food consumption of honey and beeswax contaminated with these residues considered separately does not compromise the consumer’s health, provided proposed action limits are met. In regard to residues of flumethrin in honey and in beeswax, “zero tolerance” should be applied

Severe stunting of wheat caused by the Indian peanut clump virus (IPCV), possibly vectored by Polymyxa sp

International audienc

Dynamics of Polymyxa graminis and Indian peanut clump virus (IPCV) infection on various monocotyledonous crops and groundnut during the rainy season

The progress of Indian peanut clump virus (Hyderabad isolate; IPCV-H) and its vector Polymyxa graminis in various monocotyledonous crops and groundnut was studied during the 1994, 1995 and 1996 rainy seasons in a naturally infested field in India. The roles of rainfall and temperature in the dynamics of infection by both the virus and its vector were analysed by exposing young seedlings for short periods in the field. Of the host crops studied, wheat, followed by barley, showed the highest virus incidence, although P. graminis was rarely observed in roots of wheat and was not detected in those of barley. The roots of maize, pearl millet and sorghum plants infected by P. graminis showed intense colonization by sporosori. IPCV accumulated in systemically infected maize plants; the sorghum and pearl millet cultivars studied showed a transient presence of IPCV-H. Rice was seldom infected by the virus and P. graminis was not detected in its roots. Groundnut was a systemic host for the virus, although during these experiments no P. graminis was found in its roots. Groundnut appeared to be susceptible to infection, mostly in the early stages of crop development, and the rate of IPCV-H transmission in groundnut seeds was highest (13%) for plants infected when young. The seed-transmission rate quickly decreased in plants showing symptoms 1 month after sowing. Time of infection had little influence on groundnut pod yield, which was always reduced by >60% in infected plants. There was some evidence that the quantity and distribution of rainfall influenced the incidences of IPCV-H and P. graminis: high rainfall resulted in high incidences of the virus and P. graminis, and a weekly rainfall of 14 mm was sufficient for P. graminis to initiate infection. Temperatures prevailing during the rainy season ranged from 23 to 30degreesC and were found to be conducive to natural virus transmission. These results suggest measures to be explored for controlling peanut clump disease

Etiologie de la rhizomanie de la betterave sucrière

Le virus des nervures jaunes et nécrotiques de la betterave est l'agent responsable de la rhizomanie de la betterave sucrière. La prolifération anarchique du chevelu racinaire est caractéristique de l'infection qui entraîne de lourdes pertes de rendement en sucre. L'utilisation de plantes tolérantes à la maladie maintient des rendements en sucre élevé mais conduit à la presistance de la charge virale dans le vecteur tellurique, Polymyxa betae, permettant ainsi l'apparition d'isolats contournant les résistances utilisées. La pathogenèse virale est entre autres liée à l'expression de la protéine non structurale p25, exprimée par l'un des ARN génomiques "accessoires" du virus. Le contournement des résistances utilisées au champ semble lié à des variations de séquence de la protéine p25. Dans cette revue, la biologie moléculaire du BNYVV, de son vecteur et les moyens de lutte contre la rhizomanie seront abordés

Comparison of life history traits and oviposition preferences of Tuta absoluta for twelve common tomato varieties in Burkina Faso

The South American tomato pinworm, Tuta absoluta Meyrick (Lepidoptera: Gelechiidae), is an economically important insect pest of tomatoes. Since its discovery in Burkina Faso in 2016, the use of synthetic insecticides was favored, with many cases of treatment failure. In order to explore alternative control methods, we conducted a screening of the twelve main tomato varieties produced in the country to test two hypotheses: (1) Some tomato varieties are less likely to attract gravid females and be used as oviposition site; (2) Some varieties are unsuitable host plants as they allow slower development and lead to higher mortality. The varieties tested include RomaVF, KanonF1, Cobra 26 F1, FBT1, FBT2, FBT3, RaissaF1, JampacktF1, Mongal, Rio Grande, Tropimech and Petomech. Tuta absoluta fitness was largely impacted by the tomato variety, especially egg incubation time and larval and pupal stage durations. As a result, the total T. absoluta lifecycle was slower on Cobra 26 F1 and Kanon F1 (24.6 ± 1.8 and 25.8 ± 3.3 days, respectively) and faster on FBT1 and Rio grande (22.6 ± 3.0 and 22.8 ± 2.6 days, respectively). None of the variety impacted adult lifespan. All varieties were accepted as hosts by gravid females during multiple choice oviposition assays. The number of eggs laid per females was statistically similar among the varieties. We conclude that two varieties, Kanon F1 and Cobra 26 F1, have better abilities to slow T. absoluta development, limiting the number of generations while increasing the probability that natural enemies find and kill their prey.Produir

Multiplex qPCR assay for simultaneous quantification of CYP51‐S524T and SdhC‐H152R substitutions in European populations of Zymoseptoria tritici

Demethylation inhibitor (DMI) and succinate dehydrogenase inhibitor (SDHI) fungicides are currently relied upon for the control of septoria tritici blotch (STB) in European wheat fields. However, multiple mutations have occurred over time in the genes encoding the targeted proteins that have led to a practical loss of fungicide efficacies. Among the different amino acid substitutions in Zymoseptoria tritici associated with resistance to these fungicides, S524T in CYP51 (DMI target) and H152R in SdhC (SDHI target) are regarded as conferring the highest resistance factors to DMI and SDHI, respectively. To facilitate further studies on the monitoring and selection of these substitutions in Z. tritici populations, a multiplex allele-specific quantitative PCR (qPCR) assay allowing for estimation of both allele frequencies in bulk DNA matrices was developed. The assay was then used on complex DNA samples originating from a spore trap network set up in Belgium, Denmark, Sweden, and Ireland in 2017 and 2018, as well as on leaf samples with symptoms. The S524T allele was present in all field samples and its proportion was significantly higher in Ireland than in Belgium, whereas the proportion of H152R was only sporadically present in both countries. The frequency of S524T varied greatly in the airborne inoculum of all four countries; however, the H152R allele was never detected in the airborne inoculum. The method developed in this study can be readily adopted by other laboratories and used for multiple applications including resistance monitoring in field populations of Z. tritici