Farmers in Mwea have been sensitized on how to control the destructive apple snails which are threating rice production in the region.
The move comes at a time when apple snails are threatening rice production in the country’s Tebere rice scheme in Kirinyaga County.
Snails are considered a major problem in rice production and if not controlled early, an adult snail can destroy one square meter of a field overnight, leading to over 50 per cent loss in yields.
Mr Vincent Koskei, a researcher at the Mwea Irrigation Scheme said that there are over 100 species of apple snails but two species commonly known as golden apple snails are highly invasive.
The farmers, added Mr Koskei, have been equipped with the knowledge on how to distinguish the golden apple nails from the native snails through their colour and size.
“Golden apple snails have muddy brown shell and golden pinkish or orange-yellow flesh. They are bigger and lighter in colour compared to native snails with their eggs appearing bright pink in colour,” noted Mr Koskei.
The researcher said the snails spread through irrigation canals, natural water distribution pathways, and during flooding.
“When there is no water, apple snails are able to bury themselves in the mud and hibernate for up to six months and may re-emerge when water is re-applied,” said Mr Koskei.
He added the snails attack direct wet seeded rice and transplanted rice up to 30 days old, once the rice plant reaches 30-40 days, it becomes too thick, resisting the slimy animal.
Farmers in Tebere scheme have been advised to use barriers where water enters and exits the field by placing a wire or screen on the main irrigation water inlet and outlet to prevent snail entry.
Mr Koskei further explained that the critical time to manage golden apple snails is during land preparation and crop establishment or planting, specifically the first 10 days after transplanting and or during the first 21 days after direct wet seeding.
“We are advising farmers to plant healthy and vigorous seedling because transplanted rice is less vulnerable than direct-seeded rice. They should also raise seedlings in low nursery beds, and delay transplanting to reduce missing hill snail damage” he added.
After transplanting, the rice crop is generally resistant to snail damage and snails are actually beneficial by feeding on weeds.
To decimate the rising snail numbers, the official said communities should collaborate through, “conducting mass snail and egg collection campaigns involving the whole community during land preparation and planting or crop establishment.”
He added, “farmers can also destroy by handpicking and crushing the egg masses. This is best done in the morning and afternoon when the snails are most active. Farmers are also advised to place bamboo sticks to provide site for egg-laying that allow easy collection of snail eggs for destruction”
The other control method would be to introduce domestic ducks in the fields during final land preparation or after crop establishment when plants are big enough 30-35 days after transplant, noted Mr Koskei.
“Apple snails have difficulty in moving in less than 2cm of water, so farmers can control their spread by keeping water level below the 2cm during the vulnerable stages of the rice plant” he said.