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Pests of cabbage (Brassica oleracea L Var.capitata) and Cauliflower (Brassica Oleracea L.var.botrytis) and their management
Investigations on “Pests of cabbage (Brassica oleracea L. var. capitata) and cauliflower (Brassica oleracea L. var. botrytis) and their management” were carried out at College of Agriculture, Vellayani during 2011-13. The main objective of the work was to identify the pests and natural enemies asso...
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| Format: | Ph.D Thesis |
| Language: | Undetermined |
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Vellayani
Department of Agricultural Entomology, College of Agriculture
2013
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| Summary: | Investigations on “Pests of cabbage (Brassica oleracea L. var. capitata) and
cauliflower (Brassica oleracea L. var. botrytis) and their management” were carried out at
College of Agriculture, Vellayani during 2011-13. The main objective of the work was to
identify the pests and natural enemies associated with cabbage and cauliflower and to
evolve pest management strategies.
Analysis of pest fauna in cabbage and cauliflower revealed that the crops were
attacked by eighteen pest species. The occurrence of pierid butterfly Appias lyncida Cramer
on cruciferous crops is reported for the first time. The key pest affecting the crop grown in
plains was the cut worm Spodptera litura (Fabricius) and in the hilly tracts it was Plutella
xylostella (Linnaeus). Damage caused by S. litura was 30% in cabbage and cauliflower and
that by P. xylostella was 38% to heads and 26 % to curds. Two coccinellid predators
Chilomenes sexmaculata Fabr. and Coccinella transversallis Fabricius and the syrphid,
Ischiodon scutellaris Fabricius were identified from the colonies of aphid, Lipaphis erysimi
(Kaltenbach). One parasitoid, Protapanteles sp. was identified from larvae of Plusia
signata Fab.
Further investigations were focused on S. litura, the major pest in plains. Detailed
studies on biology of the pest revealed high fecundity and survival percentage of all the life
satges (80 -100), favouring high feeding potential and rapid buildup of population. S. litura
incidence in cabbage reached the peak level at head fill stage (13WAP) in cabbage and in
cauliflower the peak was observed at curd development stage (12WAP). Correlation
studies of the population with weather parameters revealed that the pest and abiotic factors
did not show any consistent association. The relative importance of different abiotic factors
that acted upon the pest varied during the period.
Preliminary screening of entomopathogens, botanicals and new generation
insecticides undertaken under laboratory conditions revealed that, GE 2%, NSKE 5 %, SFE 10 % and the synthetic insecticides, indoxacarb 0.008%, and cypermethrin 0.03% were
equally effective as the treated check, malathion 0.15%.
Field studies conducted using the above selected treatments revealed that the
reduction in population of S. litura was maximum with indoxacarb 0.008%, followed by
cypermethrin 0.03% and the treated check, malathion 0.15%. Among the botanicals GE 2%
was found to be the most effective in reducing the population, followed by 5% NSKE.
Management of S. litura had a significant effect on yield of cabbage and cauliflower.
Indoxacarb 0.008% resulted in 29.37 per cent increase in net yield of cabbage. The effect of
cypermethrin 0.03%, malathion 0.15%, GE 2% and NSKE 5% were also noteworthy in
increasing the yield by 23.07 to 28.35 per cent. In cauliflower, there was a yield increase of
53.38 to 60.07 per cent, indoxacarb 0.008%, cypermethrin 0.03%, malathion 0.15%, 10%,
NSKE 5% and GE 2%. Samples analysed for residues, at the time of harvest revealed that
the mean residue of indoxacarb 0.008%, and cypermethrin 0.03% were below detectable
limit.
From the above study it is concluded that, the key pest of cabbage and cauliflower
grown in hilly tracts was DBM and that in the plains was S. litura. S. litura can effectively
be managed by adopting management strategies in the true leaf, cupping and early head
formation or curd initiation stages of these crops. Indoxacarb 0.008% and cypermethrin
0.03%, can safely be used as there was no residual problems. Considering the ecological
and economic factors, spraying 2 % GE or 5 % NSKE is the safer.
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