The glasswing leafhopper, or rather the diseases it transmits, cause great damage to German arable crops. The impact is greatest in sugar beets and potatoes, but damage also occurs in vegetables such as onions, carrots and beetroot. The situation is being closely monitored in the Netherlands.
For several years now, the German agricultural sector has been on edge because of the Schilfglasflügelzikade or glasswing cicada in Dutch. For several years, this has caused yield losses of up to 25% in sugar beets, but is now also increasingly causing problems in potato cultivation. Yield reductions of up to 75% are seen there. The damage is mainly observed in southern Germany, but the cicada is increasingly advancing to the north and east.
Two diseases
It is not the cicada itself that causes direct damage, but the diseases SBR (Syndrome Basses Richesses) and RTD (Rubbery Taproot Disease) that it brings with it. The nymph of the cicada lives in the soil, on the roots of the plant, and thus transmits the SBR bacteria. This bacteria causes great damage to yields and therefore also to vegetable crops. RTD is a problem in sugar beets and is also called Stolbur, a phytoplasma.
The clinical picture of SBR in sugar beets is very similar to the yellowing virus or magnesium deficiency. With RTD, dormant beets are observed, after which discolouration of the leaves also occurs later. Both diseases can also be found together in a plot, which makes the damage even greater. In 2023, SBR was also found in Dutch beet samples. Due to the emergency situation in our eastern neighbours, the IRS and Cosun are checking extra closely this year.
Exemption
The German media is now full of reports about the small creature, which is causing headaches in the agricultural sector, says DBV chairman Joachim Rukwied of the agricultural interest group in the country. Damage is now occurring in Baden-Wortenberg, Rhineland-Palatinate, Bavaria and Hesse. The cicada has also been found in Lower Saxony and Saxony-Anhalt. Exemptions are being issued at the state level to combat the cicada with insecticides. The DBV is advocating that exemptions to be issued much more widely to be allowed to spray.
Last year, 75.000 hectares of sugar beets in Germany were affected by the two diseases. In 2023, this will be 40.000 hectares. The extent of the damage to potatoes has not yet been calculated, but the German potato organization Unika estimates that 65.000 hectares are at risk.
On edge
The cicadas start flying in mid to late May. Warm and sunny weather has contributed to the insect now being a problem. There is a warning service for sugar beets, which issued a report in early June. Cosun calls on growers to report suspicious damage to beets to their cultivation supervisor. The IRS can then investigate whether it is actually SBR or RTD.