Atheta coriaria is a rove beetle that has several soil organisms that are harmful to crops on its menu. Its preferred delicacy is any life form of sciara fly (eggs, larvae and pupae) as well as Ephydridae, otherwise known as shore flies. Sciara fly larvae feed on living material such as roots and shoots. The feeding damage caused by the sciara fly makes the plants vulnerable to secondary plant diseases such as Pythium, Phytophthora, Botrytis, Fusarium and Verticillium. Atheta coriaria also has a controlling effect on Frankliniella occidentalis (Western flower thrips) in the 2nd larva phase and on moths such as Duponchelia (eggs and small larvae).
Life cycle and efficacy
After the egg stage, Atheta coriaria goes through three larval stages and a pupal stage before reaching the adult stage. The larvae have a yellowish colour, are elongated and measure up to 4 mm. The pupae spin a white cocoon with soil particles. The adult beetles are also oblong and about 4 mm in length. They are a shiny dark brown/black colour and have a hairy body with short elytra. The beetles can fly which means that they disperse to all parts of the crop quickly. Atheta coriaria seeks predators in all stages of its life cycle. The larvae and adults are rovers; they use their jaws to kill and eat their prey. In the greenhouse, the life cycle from egg to adult will take 3 to 4 weeks depending on the temperature. The adults will then live for another 3 to 4 weeks and will lay 100-125 eggs.
Deployment and dosage
Atheta coriaria can be deployed for numerous ornamental and vegetable crops suffering from the pests mentioned above. The beetles can be distributed on mineral wool, potting compost, coir, or any other substrate. Low humidity conditions can be detrimental to population development of Atheta coriaria. It is best to distribute the beetles in the morning or evening. To promote the effectiveness, a second batch of beetles can be released a week later, with the same numbers per square metre. It is best to distribute the beetle/compost mixture in small quantities on the soil under the plants. This will ensure that an area of the greenhouse is sufficiently densely populated with Atheta coriaria to be effective. After a few weeks, the spread of harmful insects will stop or their numbers will be reduced. You will find the Atheta coriaria larvae in the soil, and the beetles at moist places where there is damaged or decaying plant material.
Atheta coriaria is supplied in a tube (500 individuals), bucket (3,000 individuals) or a breeding bucket (500 individuals). The tubes and buckets are filled with rove beetles and a mixture of potting compost and vermiculite as mixture for spreading.The shelf life is short, the product should be kept at a temperature of 10-15°C with RH of 85% or higher.