Evidence for pollinator cost and farming benefits of neonicotinoid seed coatings on oilseed rape.

Chronic exposure to neonicotinoid insecticides has been linked to reduced survival of pollinating insects at both the individual and colony level, but so far only experimentally. Analyses of large-scale datasets to investigate the real-world links between the use of neonicotinoids and pollinator mortality are lacking. Moreover, the impacts of neonicotinoid seed coatings in reducing subsequent applications of foliar insecticide sprays and increasing crop yield are not known, despite the supposed benefits of this practice driving widespread use. Here, we combine large-scale pesticide usage and yield observations from oilseed rape with those detailing honey bee colony losses over an 11 year period, and reveal a correlation between honey bee colony losses and national-scale imidacloprid (a neonicotinoid) usage patterns across England and Wales. We also provide the first evidence that farmers who use neonicotinoid seed coatings reduce the number of subsequent applications of foliar insecticide sprays and may derive an economic return. Our results inform the societal discussion on the pollinator costs and farming benefits of prophylactic neonicotinoid usage on a mass flowering crop.

Sudden deaths and colony population decline in Greek honey bee colonies.

During June and July of 2009, sudden deaths, tremulous movements and population declines of adult honey bees were reported by the beekeepers in the region of Peloponnesus (Mt. Mainalo), Greece. A preliminary study was carried out to investigate these unexplained phenomena in this region. In total, 37 bee samples, two brood frames containing honey bee brood of various ages, eight sugar samples and four sugar patties were collected from the affected colonies. The samples were tested for a range of pests, pathogens and pesticides. Symptomatic adult honey bees tested positive for Varroa destructor, Nosema ceranae, Chronic bee paralysis virus (CBPV), Acute paralysis virus (ABPV), Deformed wing virus (DWV), Sacbrood virus (SBV) and Black queen cell virus (BQCV), but negative for Acarapis woodi. American Foulbrood was absent from the brood samples. Chemical analysis revealed that amitraz, thiametoxan, clothianidin and acetamiprid were all absent from symptomatic adult bees, sugar and sugar patty samples. However, some bee samples, were contaminated with imidacloprid in concentrations between 14 ng/g and 39 ng/g tissue. We present: the infection of Greek honey bees by multiple viruses; the presence of N. ceranae in Greek honey bees and the first record of imidacloprid (neonicotonoid) residues in Greek honey bee tissues. The presence of multiple pathogens and pesticides made it difficult to associate a single specific cause to the depopulation phenomena observed in Greece, although we believe that viruses and N. ceranae synergistically played the most important role. A follow-up in-depth survey across all Greek regions is required to provide context to these preliminary findings.

Management of plant health risks associated with processing of plant-based wastes: a review.

The rise in international trade of plants and plant products has increased the risk of introduction and spread of plant pathogens and pests. In addition, new risks are arising from the implementation of more environmentally friendly methods of biodegradable waste disposal, such as composting and anaerobic digestion. As these disposal methods do not involve sterilisation, there is good evidence that certain plant pathogens and pests can survive these processes. The temperature/time profile of the disposal process is the most significant and easily defined factor in controlling plant pathogens and pests. In this review, the current evidence for temperature/time effects on plant pathogens and pests is summarised. The advantages and disadvantages of direct and indirect process validation for the verification of composting processes, to determine their efficacy in destroying plant pathogens and pests in biowaste, are discussed. The availability of detection technology and its appropriateness for assessing the survival of quarantine organisms is also reviewed.

Development of real-time RT-PCR assays for the detection of Cucumber vein yellowing virus (CVYV) and Cucurbit yellow stunting disorder virus (CYSDV) in the whitefly vector Bemisia tabaci.

Reverse transcription followed by real-time PCR assays based on TaqMan chemistry have been developed for the detection and quantification of Cucumber vein yellowing virus (CVYV) and Cucurbit yellow stunting disorder virus (CYSDV) in individual adults of the whitefly vector Bemisia tabaci. The method includes an internal control for the detection of a gene from B. tabaci to compensate for variations in extraction efficiency. The assays designed were used to estimate proportions of viruliferous whiteflies collected from commercial greenhouse-grown crops in Spain. In a significant number of whiteflies, both viruses were detected and their amounts were estimated. The assays could be used to assist risk assessment of CVYV and CYSDV which constitute limiting factors in cucurbit crops. They are also suited to investigating the epidemiology and plant-virus-vector relationships in these diseases.

Occurrence of two different types of RNA-5-containing beet necrotic yellow vein virus in the UK.

Two types of RNA-5-containing beet necrotic yellow vein virus (BNYVV) have been detected in the UK at different sites in Norfolk. On the basis of nucleotide (nt) sequence comparisons, one virus source (UK-MH) was clearly identified as P type BNYVV, a virus type that had previously only been detected in two widely separated parts of the world, France and Kazakhstan. The other virus source (UK-FF) has a complex genome composition. The analysed portions of its RNAs 2 and 4 are closely related to the corresponding portions in the RNAs of the East Asian A type isolate S, whereas those of its RNAs 1 and 3 resemble P type RNA 1 from Kazakhstan and European A type RNA 3, respectively. Interestingly, the P25 encoded on its RNA 3 has an unique TYHG tetrad in the highly variable amino acid positions 67-70. RNA 5 of the UK-FF BNYVV source shares properties with P type RNA 5, but also with East Asian types of RNA 5. The possible origin and epidemiology of BNYVV types is discussed.