Agriculture Reference
In-Depth Information
(a)
(b)
Figure 18.22 (a) Flea beetle damage on radish leaves; (b) Lily beetle
Piercing
and
sucking
mouthparts
Black
spots
Fused
body
segment
Four
pairs of
legs
Glasshouse red spider mite ( 100)
Figure 18.24 Two-spotted mite. Note that this
pest is very small (0.8 mm) and can easily escape a
gardener's attention
Figure 18.23 Gooseberry sawfl y damage
normally help in the breakdown of soil organic
matter . They may cause damage in greenhouses on
cucumber roots.
serious pests on plants. The life cycle is composed of
egg, larva, nymph and adult stages.
Two-spotted mite or glasshouse red
spider mite ( Tetranychus urticae )
Mite pests
The mites ( Acarina ) are grouped with ticks, spiders
and scorpions in the Arachnida . Although similar to
insects in many respects, they are distinguished from
them by the possession of four pairs of legs , a fused
body structure (no clear abdomen or thorax) and the
absence of wings (Figure 18.24). Many of the tiny
soil-inhabiting mites serve a useful purpose in breaking
down plant debris. Several above-ground species are
Damage . The piercing mouthparts of the mites inject
poisonous juices which cause localized death of
leaf cells. This results in a fine mottling symptom
on the leaf. In large numbers, the mites can kill off
leaves and eventually whole plants. Numerous fine
silk strands are produced in severe infestations
(FigureĀ 18.25b)
Search WWH ::




Custom Search