Management of giant african snail achatina fulica (Bowdich)
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Date
2016
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Department of Agricultural Entomology, College of Agriculture, Vellayani
Abstract
A study on “Management of giant African snail Achatina fulica (Bowdich)”
was conducted at Department of Agricultural Entomology, College of Agriculture,
Vellayani, Thiruvananthapuram, during 2014-16. The objectives were to study the
distribution of A. fulica and its natural enemies, if any and to develop effective
management strategy using plant extracts, chemicals and pathogenic nematodes.
In order to find out the distribution of giant African snail (GAS), a survey was
conducted in ten panchayaths of Thiruvananthapuram district. Among the ten
panchayaths surveyed, Pulimath and Vakkom panchayaths recorded highest number of
adults and juveniles of GAS respectively. Flat headed worm/ hammer headed worm
and crow pheasant, Centropus sinensis Stephans were recorded as natural enemies.
The management study included evaluation of different baits and traps for
attracting GAS and evaluation of different chemicals, botanicals and pathogenic
nematodes against GAS.
Among the different baits evaluated for GAS, papaya leaf pulp (0.5 kg) +
jaggery (100 g) + wheat flour (0.5 kg) was identified as best treatment with highest
number of individuals attracted (11.65). Mud pot with fermented bait (wheat flour 500g
+ jaggery 200g + yeast) and copper sulphate 6% as poison was found to be superior
trap over others, with 20 snails trapped per pot.
Among different chemicals evaluated, copper sulphate 5% showed a quicker
mortality (43.07 per cent) at 24 hours after treatment (HAT). The effect was continued
and at 72 HAT, copper sulphate 5% shown significantly higher per cent mortality
(93.33) over others and which was followed by copper oxychloride 4% and copper
hydroxide 4% with, a mortality of 80 per cent. Results of the experiment to evaluate
ovicidal action of chemicals against GAS revealed that, none of the chemicals found
effective.
The copper sulphate 5% was found to be the best poison bait among different
baits evaluated with 80.29 and 88.71 per cent mortality of GAS at 24 HAT and 48 HAT
respectively. The treatments: spinosad 45 SC @ 0.60 ml L-1 (T2), spinosad 45 SC @
0.90 ml L-1 (T3), carbosulfan 25 EC @ 2.00 ml L-1 (T8), carbosulfan 25 EC @ 3.00 ml
L-1(T9), chlorpyriphos 20 EC @ 6.00 ml L-1 (T12), metaldehyde @ 6.00 g m-2 (T21),
copper sulphate @ 3.00 % (T23) and copper sulphate @ 5.00 % (T24) recorded 100
per cent mortality of snails at 72 HAT in the laboratory.
The laboratory evaluation of eight botanicals at varying concentrations revealed
that, they were not effective in causing mortality, ovicidal action and antifeedant effect
against
A. fulica. But comparitively higher per cent leaf area protection was
observed for
Azadirachta indica seed extract @ 15 %, Annona squamosa seed
extract @ 15 % and Lantana camara leaf extract @ 25%, among which A. indica seed
extract @ 15 % was found to be significantly superior to other treatments.
Two species of nematodes from the genus Heterorhabditis (H. bacteriophora
and
H. indica), three species from the genus Steinernema (S. abbasi, S. bicornutum
and S. carpocapsae) and two species from Rhabditis were tested against GAS.
However, these nematodes were nonpathogenic to A. fuica.
The study concluded with the following results. Higher population of adults and
juveniles of GAS was observed from Pulimath and Vakkom panchayaths respectively.
Papaya leaf pulp (0.5 kg) + jaggery (100 g) + wheat flour (0.5 kg) was the best bait
evaluated against GAS. Mud pot with fermented bait and poison was superior to other
traps evaluated. Copper oxychloride 4%, copper hydroxide 4% and copper sulphate 5%
were effective chemicals evaluated against GAS. Copper sulphate 5% was found to be
the best treatment among various chemicals evaluated as poison baits. Spinosad 45 SC
@ 0.60 ml L-1 and 0.90 ml L-1, carbosulfan 25 EC @ 2.00 ml L-1 and 3.00ml L-1,
chlorpyriphos 20 EC @ 6.00 ml L-1, metaldehyde @ 6.00 g m-2and copper sulphate 3%
were also identified as effective poison baits under laboratory conditions.
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