Biological control of beetles that damage stocks by store chalcids

The store chalcids are naturally occurring antagonists of some important beetle larvae that damage stocks. Especially their ability to find larvae living hidden in the grain makes the parasitic wasps very interesting for the biological control.

The beetle larva is stung through the grain and is paralyzed. The parasitic wasp bores its ovipositor into the grain and lays an egg next to the beetle larva. The larva of the parasitic wasp hatches and feeds on the beetle larva during its growth and thus makes it harmless. After the pupation, the adult store chalcid gnaws a hole into the grain and leaves it looking for further pests. At about 26 °C (70% humidity) the development takes about 3 weeks, whereby the females live approximately for two weeks after hatching.

The following beetle species are parasitized:

  • Australian spider beetle
  • Flour beetle
  • Pea beetle
  • Lesser grain borer
  • Bean beetle
  • Grain weevil
  • White-marked spider beetle
  • Golden spider beetle
  • Shiny spider beetle
  • Rice weevil
  • Tobacco beetle

A female Lariophagus is only 2-3 mm in size. These beneficial insects are black and shimmer slightly metallic.

Additionally to the use of Trichogramma, the store chalcids can also be used against the larvae of the angoumois grain moth (Sitotroga cerealella) that unlike other moth larvae develop inside the grains.

Treatment of empty rooms for preventive use: 1 unit per 25-100 qm, temperature from 15-20 °C. Repetition after 14 days

In the grain warehouse: 1 unit per 25 qm, at temperatures from 15-20 °C.

The first treatment takes place immediately before or after placing the grain into stock. Repetition after 14 days.

Application recommendation LarioTop® :

Control of the sawtoothed grain beetles

The parasitic wasp Cephalonomia tarsalis is specialized in sawtoothed grain beetles and can localize the beetle larvae for several meters due to the small droppings. It is about 2-3 mm in size and black. When stung by the parasitic wasp, the beetle larvae are immediately paralyzed. Per beetle larva up to two parasitic wasps develop. After about 3 weeks, new wasps hatch from the cocoons.

As the sawtoothed grain beetle often appears after an infestation with wheat weevil, Cephalonomia tarsalis and store chalcids can be released together.
At the moment, two other beneficial insects are tested for the biological control of important pests: the parasitic wasp Holepyris sylvanidis against the mill pest confused flour beetle (Tribolium confusum) and the pirate bug (Xylocoris flavipes) against the material pest khapra beetle (Trogoderma granarium).