This is a great time of year isn't it? The weather is warming up and it's a fantastic time to be outside. But we aren't the only ones who love the warm weather; many organisms (both plant and animal) are becoming more active. As plants grow and flowers bloom, there are many potential pests that are very pleased that the weather is warming up. Insects, arachnids and terrestrial crustaceans (which includes slaters) have come out of hibernation to start feeding and begin reproducing.
The range of pests that can cause problems to your plants is enormous. It is vital that you are able to effectively analyse the symptoms of a pest attack and that you correctly diagnose the organisms that are causing the attack. One very effective method of observation when you are trying to diagnose a pest infestation is to collect samples from the plant for closer analysis.
Do you know the best sampling method to use?
I highly recommend taking a representative sample. A representative sample is when you take samples in different sections of the area that is being monitored. For example, when monitoring a garden bed you don't just take samples from the front row or samples from just one side of the bed. You take samples across the whole garden bed in a zigzag type of pattern.
The type of viewing and sampling technique that you use depends upon the type of insect or arachnid that you are trying to see and collect. There are traps for crawling insects, nets for flying insects and hand collection techniques for mites. Let's have a look at the various types of viewing and sampling techniques and the organisms that they are designed to catch.
Click on each piece of viewing and sampling equipment to find out more.
Beating trays are also known as beating boards or beating sheets and are made of durable cloth sheets, preferably white, stretched onto a wooden frame.
The trays are usually between 50cm and 1m square in size and are held or placed under plant foliage. The plant branch or foliage is struck sharply with a stick or hand to dislodge any insects or mites onto the tray.
The specimens that fall onto the sheet are carefully removed either by hand, by forceps (tweezers), a moistened brush or by using an aspirator. Beating sheets are used to collect crawling insects that do not fly, for example, beetles. The number of insects or mites is then counted to determine if a control measure is required.
A mouth aspirator consists of a bottle (at least 7cm x 2.5cm) fitted with a two-holed rubber stopper.
To use the aspirator, air is drawn through the apparatus by sucking on the rubber tube with the mosquito netting (which prevents insects being sucked into the mouth of the collector). The insect is sucked into the chamber through the other tube, which is pointed towards the insect or mite.
Sweep nets are used to collect winged insects.
The net is swept along a branch or the top of grass using a long sweeping motion. Another fast sweep is made through the air to force any insects to the bottom of the net.
Hand lenses are used in the field to examine materials close-up.
Hand lenses come in different magnifications, but the most commonly used ones are 10X and 20X magnification.
Pitfall traps are made out of a cuplike container and are buried in the ground.
The top of the container is level with the ground. Bait (eg food that the insects eat) is placed into the trap and crawling insects fall in and are unable to crawl out.
Pitfall traps can also contain a killing agent such as ethanol, which helps preserve the invertebrate that is caught in the trap.
Sticky cards are suspended 10cms over the benches, doorways and vents, and trap adult insects as they fly around. The insect is attracted to the yellow colour.
Editor's note
