Throwthrowback: Last last post, I was talking about the impact of chemical pesticide on sustainable agriculture. Biological control is one of the important component in Integrated Pest Management (IPM). Let's talk about natural enemies and biological control on this post!
So..... what is natural enemies actually? We have heard of our enemies' enemies are our friend right? Hahaha! Exactly, please welcome the beneficial insects a.k.a. natural enemies that are the biggest fear of the pest insects!
Uhm, it doesnt work that way... Hahaha
There are actually plenty kinds of beneficial insects exist in nature, namely:
- Predators: e.g. spider
- Parasitoids: e.g. wasp
- Pollinators: e.g. bees
- Decomposers: e.g. certain beetles
The spider D:
The wasp 0.o
The bees <3
The..... dung beetle...? Yup decomposer, thank him!
Predators and parasitoids are especially important in biological control. However, the application of pesticide disrupt the entire agroecosystem, and therefore the natural biocontrol system fails.
What about Malaysia? Yes we are still a heavy user of pesticide hence biological control is not given much attention. However, we do have successful cases of biological control already. One of the early most successful biological control is initiated by my professor (Prof. Peter Ooi A.C) (He published many papers on biological control).
In Filipino, farmer spraying rice field with pesticide.
"Euphoria of pest control".
One of the successful case happened in rice field.
Casts:
Farmers
Pest - Brown plant hopper (BPH) (nasty pest in rice field)
Natural enemies - Wolf spider (the hero)
BPH, the evil bastards in rice field.
Wolf spider, ingesting BPH. Truly hero *salute*
In a rice field, spraying of pesticide to control BPH is a common practice done by the farmers. (Because they are told to do so! And government is even subsidizing the pesticide -.-) Yup the BPH are killed, so do the natural enemies. Pest, tend to recover in population faster, and gaining resistance at the same time. Now the problem comes, the natural enemies are gone! Therefore, secondary outbreak is worse and nasty.
Secondary outbreak explained by Kelly.
An experiment is thus conducted in the rice field. By using exclusion cage method.
cage 1 - cage closed, excluding predators
cage 2- cage opened, predators able to come in.
The result?
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Cage 2 win! with relatively lower number of BPH. This shows that predators are at work.
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Another example we will be talking about parasitoids, well in the next post :P
Hint: a wasp :P
See you guys ;)
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