Flat-headed
BIOLOGICAL CONTROL OF FLAT-HEADED ROOTBORER
Capnodis tenebrionis
The flat-headed rootborer is a common pest in Mediterranean regions and occurs on stone fruit trees such as cherry, apricot, peach, nectarine, plum and almond. It is 15-20 millimetres long, crested with a retracted head and has dark wing covers.
LIFE CYCLE
The life cycle of the flat-headed rootborer lasts 13 months. The adult beetles emerge from the ground in April and lay their eggs in the soil around the trees from June to August.
The larvae hatch in the soil and eat their way through the roots and tree trunks in autumn and winter, where they pupate in spring.
In August, new adult beetles hatch and bore their way out through the tree trunk. This causes the typical damage of the boreholes up to approx. 50 cm trunk height.
The beetles overwinter in the soil and reappear in April to lay their eggs again. Larvae can be found all year round.
Capnodis larvae under the tree bark
DAMAGES CAUSED BY THE LARVAE
The main damage is caused by the larvae: in the autumn and winter months, they feed in tunnels between the wood and bark through the roots and into the tree trunks up to a height of approx. 50 cm. Adult beetles feed on the leaves in August.
Trees of stone fruits such as cherry, apricot, peach, nectarine, plum and almond are particularly affected.
CONTROL FLAT-HEADED ROOTBORER WITH BENEFICIAL NEMATODES
Nematodes are tiny, thread-like soil organisms about 0.6 mm long. They are natural enemies of the flat-headed rootborer. The product nemastar® contains nematodes of the species Steinernema carpocapsae. This species specialises in peach jewel beetle larvae, among other things, and can use them for its own nutrition and reproduction. The nematodes are supplied live in a powder. To apply them, they should be mixed with water exactly according to the instructions on the packet and applied to the affected areas.
With the exception of the eggs of the flat-headed rootborer, all stages are susceptible to Steinernema carpocapsae nematodes. Adult beetles, newly hatched larvae, all larval stages and pupae.
Nematodes of the species Steinernema carpocapsae
APPLICATION OF THE NEMATODES
It is applied either via the irrigation system, by injection into the soil or, in the case of individual trees, by infiltration (drenching).
Application period: April/May and September/October
The nematodes should be applied in spring (April/May) and autumn (September/October). In most affected regions, it is too hot for nematodes to be applied in summer.
Preventive treatment in autumn is normally sufficient.
Application of nematodes via drench-application
nemastar® should only be applied to moist soil. If the soil is too dry, it must be watered beforehand. The dosage of nemastar® depends on the size of the infested trees: 2 million nematodes are sufficient for small trees, while up to 10 million nematodes per tree are required for large trees.
When applying by drenching, the soil around the tree trunk is removed to a diameter of approx. 1.5 metres and a depth of 10 cm. As soon as the water has seeped away, the soil is refilled after application.
When applying by drip or sprinkler irrigation, the water should be allowed to run for 2 hours before and 3 hours after application.
Over 6,000 ha have already been treated with nemastar® in Spain. The efficiency rate is 70-85%.
