Moku Virus in Invasive Asian Hornets, Belgium, 2016.

We report the detection of Moku virus in invasive Asian hornets (Vespa velutina nigrithorax) in Belgium. This constitutes an unexpected report of this iflavirus outside Hawaii, USA, where it was recently described in social wasps. Although virulence of Moku virus is unknown, its potential spread raises concern for European honeybee populations.

Targeted control of the saddle gall midge, Haplodiplosis marginata (von Roser) (Diptera: Cecidomyiidae), and the benefits of good control of this pest to winter wheat yield.

BACKGROUND: Since 2010 there has been a resurgence of the saddle gall midge, Haplodiplosis marginata (von Roser), in Belgium and several other European countries, with this pest sometimes causing severe damage in cereals. In 2012 and 2013, field trials were conducted in heavily infested fields to assess its impact on winter wheat crops and to determine efficient ways of dealing with severe infestations. RESULTS: Crop exposure to H. marginata varied with the different protection methods tried. These methods included 1-4 successive applications of lambda-cyhalothrin. Yield losses were significant, reaching 6% in 2012 and as high as 15% in 2013, and these losses were linearly related to the number of galls on stems. CONCLUSION: The trials showed that insecticide applications needed to be synchronised with H. marginata flight peaks and to target the egg hatching period. They also revealed that insecticides applied to coincide with the first flight could, in humid conditions, also reach the larvae close to the soil surface, prior to their pupation.

Protection of winter wheat against orange wheat blossom midge, Sitodiplosis mosellana (Géhin) (Diptera: Cecidomyiidae): efficacy of insecticides and cultivar resistance.

BACKGROUND: In 2012 and 2013, Sitodiplosis mosellana (Géhin) flights occurred during the susceptible phase of wheat development in Belgium. The protection against this midge afforded by various insecticides was assessed in infested fields on four winter wheat cultivars (susceptible or resistant, and early or late heading). RESULTS: The insecticides sprayed at the right time reduced the number of larvae in the ears by 44-96%, depending on the product. For Julius, the cultivar (cv.) most exposed to S. mosellana in 2013, the mean yield gain resulting from insecticide use was 1558 kg ha(-1) (18%). In the same year, insecticide use resulted in a yield gain of 780 kg ha(-1) (8%) for the cv. Lear, in spite of its resistance to this pest. The link between yield and number of larvae counted in the ears was a logarithmic relationship, suggesting an important reduction in yield, caused either by the damage inflicted by young larvae that died at the start of their development or by the activation of costly reactions in plants. CONCLUSION: The study showed that, in cases of severe attack, the timely application of insecticide treatments can protect wheat against S. mosellana, and that even resistant cultivars can benefit from these treatments.