SLUGS AND SNAILS.

Auckland Star, Volume LXVII, Issue 57, 7 March 1936, Page 6 (Supplement)

SLUGS AND SNAILS.

The recent wet weather and the probability of a continuance will mean that tho slug and snail population will be more numerous than usual. It is very difficult to control these pests, especially during damp or wet weather, but by continually waging war upon them and their breeding places it is possible to lessen their numbers if an absolute clearance is not possible. A short account of their habits and life history will assist in explaining and showing how important it is to be continually taking every opportunity of controlling them by any method at hand. Slugs are unprotected by an external shell, but they have a small flat shelllike plate, hidden under the skin in the front region of the body. Snails, oil the other hand, have a large shell into which the whole body can be withdrawn. They also have tho power of closing this shell completely by means of a hardened plate wliir-lL is spread over the opening into the shell. The common grey field slug breeds in largje numbers under old rubbish, and for this reason it is unwise to allow any refuse to accumulate. It is estimated that a single slug will lay as many as 500 eggs during one season; thus it is easy to understand the rapidity with which they

increase. Often a warm shower In spring will cause the ground to be literally covered \vitli slugs, and the question is, where do they all come from? An examination of the soil during the drier parts of the day will reveal them securely nestled away under small stones and the coarser particles of earth. A sniall 6pecies, known as tho bulb or root-eating slug, passes the day under ground, from where it makes its exit at night, and feeds'" freely on any green vegetables that may be within reach. One noticeable feature of slugs and snails is the of slimy mucus these animals can produce, and which especially interferes with killing them. This slime cannot be produced continuously for a long time, but it is necessary that whatever irritant powder is used for killing sufficient be used to penetrate this slime and reach the skin. Both snails and slugs have male and female sexual organs in the same individual. Both deposit eggs, and the young resemble the adults. Slugs lay their eggs in the earth and under rubbish from October right on till the winter. The eggs are round, milky, opaque bodies, and are deposited in bodies of ten to fifteen. In from three

to four weeks they develop into young slugs, which arc like the parent, but smaller and paler in colour. They love moisture and are chiefly nocturnal, hiding during the day under stones or in the soil. Somo slugs do not reach maturity for a year or so. They then lay eggs and die. Others may live for four or five years. One group of slugs known as "Testacella" are worm killers. They may be recognised .by the small shell being external. They hunt and destroy earthworms and grubs in the soil, and may be said to bo beneficial. Snails are similar, in many ways, to slugs, except that they are provided with shells. The large garden snail is the most common and one of the most widely distributed. It is tho largest garden species, easily distinguished by its brown shell marked with pale zigzag lines. Eggs are laid in the earth in batches about 00 or 70 in a heap. The eggs are white, shiny globular bodies, which hatch in about fifteen days. The young snails have very thin, transparent shells and grow rapidly. They often occur in large masses united by the socalled cpipliragm, which they form close to the mouth of the shrill. The natural enemies of slugs and snails are thrushes, blackbirds and starlings. Toads are great devourers of slugs. Ducks are also very fond of them and will help to keep a garden clean. Prevention and remedies are many, but few are of any

! value unless they are persisted in. Dampness is in their favour, hence drainage assists to keep them away. Dressings of «soot and lime and also superphosphate help to drive them away, but applications of these cannot be applied often enough to be very effective against the slug without injury to the plants meant to protect. Lime sulphur solution will also control when it is convenient to use it. Arsenate of lead sprayed on the plants when small will get rid of quite a number by poisoning their food, but later on when plants are large or vegetables are beginning to mature this method is expensive and is not advisable in tho case of vegetables. Herbaceous plants such as delphiniums can be protected during winter by having the crowns covered with an inch or so of coarse sand or fine scoria. The best method of control is cultivation and the strict elimination of all rubbish and breeding places. Heaps of fallen leaves, weeds at the foot of fence posts or under hedges, rubbish heaps, especially heaps of sticks or branches, all such should be cleared away, buried deeply or burnt. No doubt much of the slug and snail pest is due to our ncglect of what may be termed garden hygiene.