What Are Nematodes?
So what are nematodes exactly? That is a very good question. For many the first time they hear about these microscopic little creatures are in the context of pest control, or more accurately biological control.
Biological control is a form of pest control which utilises other creatures to control the offending pest.
Nematodes are a very diverse form of life. It has been estimated that the number of different species of nematodes approaches a staggering one million, although only about 20000 have been officially categorised. They are found in nearly all the varied environments that the earth has to offer, equally at home at the bottom of the ocean, deep within the earth or even in the snow. Most species are very small, unseen to the naked eye, but there are a few larger species. One species in particular grows to nearly eight metres in length but thankfully only found in sperm whales.
In appearance they are long and narrow, resembling a worm, hence there are sometimes referred to as ‘roundworms’. The actual name nematode in part derives from the Greek work ‘nematos’ which means ‘to resemble a thread’, which is of course descriptive of its appearance.
So what use can nematodes be? The nematode is a parasitic organism, as such will attack other creatures as a parasite. There are nematodes that will attack and cause serious diseases in humans, primarily through exposure to human and animal waste. Other species of nematode can cause havoc to farmer’s crops. The Potato Cyst Nematode for example, more commonly called referred to as the potato eelworm, has a particular fondness for a certain tuber like root crop.
So nematodes are bad? Not all. Some species can be very useful. As a parasite some species will attack and
kill some very troublesome pests that would otherwise like to dine out on your lovely fruit and vegetables that you have spent all year carefully growing. Slugs. C aterpillars. V ine W eevils. L eatherjackets, C hafer B ugs and A nts can all be controlled by using the correct species of nematode. The links to the left give more information about the biological control for each particular pest.
The way the nematode gets rid of such troublesome pests is quite insidious. At this point a parallel has to be drawn to Ridley Scott’s film Alien. The nematode will search out for the pest and then gain entry into the body. It will then kill the pest from the inside and lay its eggs, up to 200000 at time. These will then hatch and leave the original host, now long dead, it search of another sacrifice. All very Alienesque.
These beneficial nematodes can be purchased from many garden centres and horticultural retailers. They are usually distributed in packs that contain what looks like a fine powder, which until needed should be stored in a fridge. Before using the correct quantity of water is added to this powder to activate the nematodes and then they can be applied to the soil using a watering can. Ideally they should be applied on an overcast day with moist soil and it is important that the soil does not become dehydrated in the following 2-3 weeks. Of course the instructions on the packet should always be followed carefully. The newly applied nematodes will live in the soil for about 6 weeks (this va ries with each species) but after this a new application of nematodes will be needed. It does make them one of the more expensive pest control options, but they are very effective.