PLANT PROTECTION 1 – Pests, Diseases and Weeds

PLANT PROTECTION 1 – Pests, Diseases and Weeds
PEST CYCLE
SNAILS.
During cold weather, snails hibernate in the topsoil. The life cycle of the
common garden snail:
Snails are
hermaphrodite
(individuals have both
male and female sex
organs) and can
fertilise each other
Garden snails are
up to 25 mm across
SLUGS.
The life cycle of slugs is similar to that of snails. But there are some slight
differences.
Slugs take 1-2 years to mature to adults and may live for a few months or
a few years, depending on the species.
Adult slugs are mostly hermaphrodite and egg laying, like snails. Selffertilization
may occur in some species.
Adults lay white or pale yellow spherical eggs, 2-6 mm across, in masses of
about 30 in decaying organic matter, under stones, boards or clods or in
moist soil. Many egg masses may be laid by each slug in warmer weather.
Egg laying may also occur during warm spells in winter in warm climates.
Under favorable conditions the eggs hatch in 2-4 weeks and the newly
emerged slugs, which are dull white, resemble the adults. Young slugs
initially feed on humus and grow slowly, assuming the adult coloration
when about 1 month old.
Unlike snails, slugs do not enter a resting stage during dry or cold
weather, instead during adverse cold, hot and dry weather, they may
congregate in damp sheltered situations under stones, logs and pots or in
cracks in the soil.
Slugs are greatly underestimated as pests. They shelter in cracks in
the ground and under litter where the relative humidity is 100%. They may
cause damage before and after snails have been feeding.
OVERWINTERING,
OVERSUMMERING
As adults (either feeding or in a non-feeding dormant state).
As eggs in the ground.
Snails and slugs 231