In recent years, the raspberry cane midge has caused more and more problems. In 2009, for example, the entire raspberry crop was lost on several parcels. In the spring of 2010, the Kennis- en InnovatieCentrum Kleinfruit in Randwijk (KICK - Expertise and Innovation Centre for Soft Fruit) began a study into controlling this pest. The research was presented and discussed on the open day of the KICK facility in Randwijk on 17 June.
Photo 1. Adult raspberry cane midge. The midges are only 2 mm in size. The species can be identified by its striking bowed antennas.
The raspberry cane midge affects both summer and autumn raspberries. The larvae of this midge live under the bark. The direct feeding damage caused by the larvae is usually minor. Much more important is that the wounds become an entry port for fungi that cause cane diseases. These fungal diseases usually cause the shoots to die off. With heavy infestations, much of the crop can be lost.
Photo 2. The females lay their eggs on the young raspberry shoots at locations where the bark shows growth splits or other damage. |
Controlling the raspberry cane midge is difficult. The periods in which the insects fly and lay eggs can be very long, which makes it difficult to time the spraying. The larvae hide under the bark and are consequently difficult to reach with pesticides. During the production of summer raspberries, the midges can be controlled by removing as many young shoots as possible during the first flight period in May, to prevent eggs from being laid by the first generation of insects. However, for autumn raspberries, it is not an option to remove the shoots in May. Chemical control is accomplished place by spraying Decis on the adult midges, but due to its wide spectrum effect, this agent is not compatible with integrated production methods. |
Laboratory tests have studied the effects of various species of insect eating nematodes and the fungal preparation Bio1020 on the larvae of the raspberry cane midge. These methods are preferred because they require no authorisation from the Ctgb (Board for the Authorisation of Plant Protection Products and Biocides). Bio1020 is authorised for use in raspberry cultivation.
Lifecycle
| The adult raspberry cane midge (Resseliella theobaldi) is only 2 mm in size, with an orange-red body and striking, bowed antennas (Photo 1).
The female lays its eggs on young raspberry shoots at locations where the bark shows growth splits or other damage (Photo 2). The midges lay their eggs primarily in the lowermost 50 cm of the crop. After 7 to 10 days, the larvae emerge from the eggs (Photo 3). These eat their way underneath the bark. After several weeks, the larvae are fully grown. Then they fall onto the ground and bury themselves. They pupate in a cocoon that they make themselves. In the Netherlands, the raspberry cane midge usually has three or four generations per year. The species overwinters as a larvae in a cocoon in the soil. In 2010, the first midges were observed at the Applied Plant Research station in Randwijk at the end of April. That was the beginning of the first flight. |
Photo 3. The larvae of the raspberry cane midge develop under the bark. The damage they cause creates an entry port for fungal diseases. |