Abstract:
Leaf Twister Disease (Ll'D) ('Koti kat' in Tamil) appears complex probiem to be a and a major rimitation in the cultivation of onion in the Batticaroa district. It was observed that LTD symptoms usuaily appear under rainy weather ceindition and up to r00% yierd rosses were
::f T:ill li: pjjllh
::fore, rhi s stucly was
"ono
u"tdJ to iJ""iirrrJ, rL,U,V pnmary cause ofLTD. sii infested fierds in three major oniorrg.o*ing
villages namely Karuthavarai, chettiparayam and Thettatheevu were
:j:"j*j::11']"llr. !re13a soilsamptes with damaged onion prant materials were colrected at four different Pr4rrr rocations ,.unio*if i,
field and examined precisely. Two hundred rnounted srides of nemato"due.sr, were prepared and examined to identi$z the nematodes based on their morphological characteristics. A nurnbe. of different t"y., ."r"r""* collections' taxonomic catalogues and many descriptions *"r" ur"a in the identification.
A nematode species Apherenchus avenae was identified from the soir sanrples and damaged onion prant materi ars. Apherenchus ovenae is a cosmopolitan ubiquitous a1d fungivorour r,r*utod" ";;r;;i","' *o decaying plant tissues.
