PLANT PROTECTION 1 – Pests, Diseases and Weeds

PLANT PROTECTION 1 – Pests, Diseases and Weeds
IDENTIFICATION & CLASSIFICATION
HOW EASY IS IT
TO IDENTIFY
INSECTS?
XPERT
CLASSIFICATION
SOME ARE EASY TO IDENTIFY IN A GENERAL WAY
Become familiar with the pest and beneficial insects which occur in your crop
and be able to identify them accurately. This is part of all IPM programs.
Identifying insects, mites, and the damage they cause, is usually easier
than sorting out problems associated with diseases and plant nutrition.
Scarab grub larvae in lawns are readily recognized as such. Other easy to
recognize pests include aphids on roses, sawflies on eucalypyts.
Books and computer programs illustrate groups of insects, eg flies, locusts,
thrips and flies; also pests affecting crops in particular regions, eg vegetables,
brassicas, turf, nurseries (page 224). Pocket guides are available for use in the
field. Eventually complete guides for known crop pests and diseases will be
available via mobile phones for farmers and growers.
INSECT KEYS
Although insect keys for identifying adults, nymphs, larvae and pupae of insects
generally to orders and families, and for identifying special groups of insects, eg
moth and butterfly larvae on brassica crops, have been compiled, in practice, their
use by the non-expert can be difficult. Reasons include:
The small size of some insects and allied forms.
Difficulty in recognizing, in some instances, whether the insect is an adult or
immature stage, eg a nymph.
Some closely allied pest forms resemble insects at some stages.
The large number and diversity of insect species in Australia.
Keys for identifying insects are on CSIRO’s and Lucidcentral’s websites:
www. ento.csiro.au/ education/ www. lucidcentral.org/
State websites have keys for identifying insects and damage on some crops.
NEED EXPERT HELP?
Although some insects such as scarab grubs are readily recognized as such, it
can be difficult to identify the precise species which is needed for implementing
effective control measures in commercial turf.
Similarly identifying the precise species of fruit fly damaging you crop.
DNA fingerprinting complements structural features to identify exotic pests.
A wide range of soil pests and diseases can now be identified from a single soil
sample using new Australian soil testing techniques.
Contact a diagnostic service for assistance (page xiv).
Classification of insects (Class Insecta) to orders and families is based on a wide
range of features, including:
Wing features, eg
– Winged or wingless
– Number of pairs of wings
– Size
– Texture, scales, etc
– Thickenings
– Venation, vein patterns
Life cycle, eg
– No metamorphosis
– Incomplete metamorphosis
– Complete metamorphosis
Mouthparts, eg
– Chewing
– Piercing and sucking
– Rasping and sucking
– Lapping
Antennae, eg
– Clubbed
– Feathery
Abdomen, eg
– Ovipositors, cerci
– Hairs
– Constrictions
Tarsi segments, eg
– Number
Body shape, eg
– Flattened
Thrips
(< 3 mm long)
– Small size
– Wedge-shaped
Insects and allied pests - Identification and classification 63