000			04316nam a2200181Ia 4500
999			_c26925 _d26925
003			OSt
005			20220831150507.0
008			140128s9999 xx 000 0 und d
082			_a632.3 _bSHA/PA
100			_aShabnaz Padiyath
245			_aParasitism of Hirsutella thompsonii Fischer var. synnematosa Samson, McCoy & O`Donnell on Coconut Eriophtid Mite Aceria guerreronis (Keifer)
260			_a Vellanikkara _bDepartment of Plant Pathology, College of Horticulture _c2002
502			_bMSc
520	3		_aAn investigation on "Parasitism of Hirsutella thompsonii Fischer var. synnematosa Samson, McCoy & O'DonneU on coconut eriophyid mite Aceria guerreronis (Keifer)" was carried out at the Department of Plant Pathology, College of Horticulture, Vellanikkara. The main objectives of the study were to explore the cultural, physiological, toxicological characters of the fungus, compatibility of the fungus with pesticides and botanicals and mass multiplication characteristics of the fungus, which could be used as an efficient biocontrol agent on coconut mite. The results of this investigation revealed the following conclusions. From the mite infested young nuts collected from the coconut garden of College of Horticulture, Vellanikkara, the acaropathogen H. thompsonii var. synnematosa was isolated and its pathogenicity on mite was proved. Sabouraud's maltose agar + yeast was selected as the most suitable solid medium for the growth and sporulation of the fungus. Maximum number of fruiting bodies called synnemata were produced in Richard's medium. Correlation study revealed a significant positive correlation between mycelial growth and sporulation. Ninety six per cent germination of spores of the fungus grown in solid medium was recorded after eight hours of incubation. In the different liquid media tried, Sabouraud's maltose+yeast was selected as the best for maximum dry mycelial weight and sporulation. Only twenty five per cent germination was recorded after eight hours of incubation of spores of the fungus grown in liquid medium. Maximum sporulation and germination percentage of spores of the fungus were recorded in solid media compared to liquid media. Microscopic observations showed that in all the solid media the hyphae were hyaline, septate, smooth and branched producing conical to flask shaped phialides with narrow neck. Phialides were branched often once. Spores were spherical, verrucose and hyaline. Hyphal width, phialide width and spore diameter , ranged between 3.33 urn to 3.76 urn in different solid media. Maximum number of phial ides in a unit length of hypha was in Sabouraud's maltose agar + yeast. The fungus preferred an alkaline pH of 9. But it gave satisfactory growth on a wide range of pH from 5 to 9. Growth of the fungus was recorded only in temperatures of 25 and 30oe. No significant difference was recorded in the fungal growth at humidity levels of 50 to 90 per cent. Both exotoxin and endotoxin were extracted from the liquid culture of the fungus. In closed perianth condition there was no significant difference in the per cent mortality of mites due to spraying with both the toxins, but it was superior than spraying with water (control). In open perianth condition there was no significant difference in the percentage mortality of mites on spraying with both the toxins and water. The decreasing order of the inhibition of fungal growth by insecticides/acaricides was dicofol, carbaryl, triazophos, wettable sulphur and endosulfan. The fungicides bordeaux mixture and copper oxychloride showed cent per cent inhibition of fungal growth whereas potassium phosphonate (akomin) recorded minimum inhibition over control. Among the botanicals, maximum inhibition of fungal growth was with garlic + neem oil and azadirachtin showed least inhibition. In the two phase mass production study, wheat was identified as the most promising raw substrate for sporulation and germination percentage of spores of the fungus. In the powdered substrates tried, growth was present only in loose substrates like rice bran and tea waste.
700			_aBeena S (Guide)
856			_uhttp://krishikosh.egranth.ac.in/handle/1/5810105888
942			_2ddc _cTH