Last week I received a call from farmer requesting for solutions on how to control the snails that were feasting on her cabbages - eating the leaves which resulted in reduced yields. The damage caused by the snails is similar to that of the insects, especially the holes they create on the leaves. However, it is easy to differentiate the damage caused by snails from that of other pests since it leaves a mucous trail.
The snails also chew the tender leaves of seedlings leaving the stem and eventually kill the plant. Sometimes the crops are affected during planting when they are still young while in some cases during the growing season like in cabbages where they can easily lead to shredded crops with total defoliation. The precise symptoms vary from one plant to the other but will have a degree of leaf shredding and holing.
In general, the snails and slugs primarily feed and damage ground crops such as brassicas, lettuces, and Chinese cabbages, potato tubers ripening strawberries fruits and sometimes decaying plant matter.
Snails and slugs are in the same order and cause similar damage to crops. They are hermaphrodites meaning that each has both male and the female sex organs. This means that the two individuals can mate and reproduce and also a single individual can self-fertilize increasing their population.
The difference between the snails and slugs is that the snail carries a spiral shell. The slugs usually feed above and below the soil surface causing damage to seeds, shoots, and roots. The snails are likely to be found outdoors, but they can be sometimes be found in the greenhouse.
The snail is usually found near the fence line and the stumps and is in almost all types of soils while the slugs tend to be restricted to the soils with clay content.
Solution
The adoptive effective integrated pest management best achieves the control of slugs and snails.
The pests are nocturnal hence tend to be active at night; therefore one should eliminate all places that the pest can hide during the day. This can be achieved by maintaining farm hygiene and sanitation by removing all weeds around the farm this reduces the hiding places resulting too few numbers of snail surviving.
One should also consider planting crops that are less attractive and resistant to snail and slugs like plants with grid leaves as they are harder to eat.
Land preparation should be effectively done involving the primary and secondary cultivation since the pest increases with minimum tillage which requires minimum or no disturbances of the soil.
The snail and slugs like moist places and lay their eggs in clusters beneath the leaves or other areas where the soil is damp. This means if one is using overhead irrigation one can consider shifting to drip irrigation system since it reduces humidity and surfaces that are moist making the environment less conducive for the pest.
Creating barriers also helps to reduce the population and the level of damage this involves putting gritty in the paths which will cut the body of the snail causing injuries to them. Sprinkling the copper pellets also helps to control the snail since copper acts as a repellent to the pest.
The snails and slugs can also be controlled by handpicking though it’s a tedious and inconveniencing especially on a large scale. In small scale farming, this is reasonably effective but should be done regularly to reduce the population.
Ground beetles control the snail by feeding on them though it’s not effective enough to control the pest.
Use of diatomaceous earth a natural powder made from ground up fossils which kills insects when they walk over them results to them being hydrated and eventually killing them. Spraying hot pepper helps to control the snail.
By Ann Macharia
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