Tips and tricks for monitoring pests and beneficial insects
Also, the monitoring of beneficial insects appears to have been really valuable. Reason enough for 4 Belgian practical centres to organise a programme of 4 workshops where growers, production staff and other interested parties can find out about the world of pests and natural enemies in the glasshouse. Below are a few important tips.
1 Also monitor beneficial insects!
The recognition of pests and beneficial insects is the first step in working out to what extent there is a natural balance in the glasshouse. Today, we often look only at the presence of pests to decide if a correction treatment is necessary. The role of beneficial insects is frequently not sufficiently taken into account.
For example, even in a simple sticky trap for white fly, adult individual Macrolophus can be found. This extra counting is a small inconvenience, but offers extra information in relation to the biological battle.
2 Sticky trap as instrument
Yellow sticky traps can generally be used, the blue ones are only useful for thrips. Hang the sticky traps 15 cm above the crop and renew these on time. The optimate proximity for the hanging of sticky traps is 1 sticky trap per 200-400m². These take insects away, but give you information about the damage threshold.
3 Monitor in the crop!
Mites are usually to be found in the top 4 to 5 leaves of the crop. With white fly, their eggs and the adults can be found in the head. In the middle of the crop, the larval stages can be found and underneath are adults and pupa.
4 Put the pests under pressure and be aware of the beneficial insects in your glasshouse!
If you make a schematic of the presence of pests and beneficial insects in your glasshouse, then you can get rid of your natural enemies in a more targeted and often more efficient way.
5 How do you get a large Macrolophus population?!
Put them out early is the message. It is a myth that Macrolophus don't develop during the dark winter months in your glasshouse. The development of Macrolophus doesn't depend on light, but on temperature. Once they are introduced, it is important to feed these beneficial insects with Ephestia (the eggs of the flour moth) or Artemia (= brine shrimp) or a mix of these two. One feeding every 6 to 7 weeks is ideal.
6 Be alert with the introduction of beneficial insects!
With the introduction of natural enemies, a hyperparasiting can occur. In this way, the biological fight against aphids by parasitic wasps is disturbed by secondary parasitic wasps, who parasitise the primary parasic wasps. A too large population of beneficial insects such as Macrolophus can actual damage crop and harvest.
If you missed the workshops, but want to see the presentation, that's possible! Interested parties can find the presentations on the websites of the participating test centres. Later in this season, in connection with various 'guided visits' and study afternoons, it will be discussed further in relation to the usefulness of monitoring systems, such as the principle of gridcharts.
Members of the test centres can look at courses here.
More info? Justine Dewitte, PCG