Browsing by Author "Manomohan Das, T P"

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Infectivity of Phytophthora species on cash crops of Kerala
(Kerala Agricultural University, 1986) Manomohan Das, T P; Abi Cheeran
The Phytophthora species infecting black pepper, arecanut, rubber, cocoa, coconut and cardamom in the northern districts of Kerala exhibited similar morphological characters and were identified as Phytophthora palmivora (Butler) Butler. Onl/cardamom and rubber isolates produced sexual structures on culture media. Cross inoculation studies with all these isolates yielded successful results.
Sporangial ontogeny of Phytophthora Palmivora (Butler) butler from black pepper (Piper Nigrum Linn.)
(Kerala Agricultural University, 1985) Manomohan Das, T P; Abi Cheeran
The Phytophthora species collected from black pepper from the different locations of north Kerala showed similar morphological characters and were identified as Phytophthora palmivora (Butler) Butler. Based on the growth characteristics on carrot agar, L/B {length by breadth) ratio and pedicel length of the sporangium all the black pepper isolates of P. pa/mivora obtained in the present investigation can be placed in MF1 or MF2 or MF3 (Griffin, 1977) or group I or II (Zentmyer et ai., 1977) due to the overlapping of characteristics described for them.
Survey of collateral hosts of Phytophthora palmivora (Butler) butler in pepper gardens
(Department of Plant Pathology, College of Horticulture, Vellanikkara, 1982) Manomohan Das, T P; Abi Cheeran
A survey work was conducted at six locations of north Kerala to identify the collateral hosts of Phytophthora palmivora, the causal agent of quick wilt disease of pepper, especially the weeds and economical plants growing in and around the pepper gardens. The locations were surveyed at monthly intervals during the period from May, 1981 to December, 1981. Pepper was found to be infected by Phytophthora species in all the locations surveyed. Both aerial and underground parts of the vine got infected showing typical quick wilt symptoms. The gardens in the vicinity of arecanut and rubber plantations showed heavy incidence of the disease. The Phytophthora species collected from pepper from the different locations showed similar morphological characters and were identified as P. palmivora. None of these black pepper isolates produced sexual stages on culture medium. Based on the growth characteristics on carrot agar, L/B ratio and pedicel length of the sporangium all the black pepper isolates of p. palmivora obtained in the present investigation can be placed in MFI or MF2 or MF3 (Griffin, 1977) or group 1 or 11 (zentmyer at al. 1977) due to the overlapping of chracteristics described for them. None of the weed plants growing in and around the pepper gardens was found to be attacked by Phytophthora species. But five economically important plants viz., arecanut, rubber, cocoa, coconut and cardamom were found to be infected by Phytophthora species. The Phytophthora species from these hosts showed close similarity with P. palmivora isolates from pepper and were identified as P. palmivora. All these isolates of P. palmivora can be placed in MFI or MF2 or MF3 (Griffin, 1977) or group 1 or 11 (zentmyer et al. 1977). The cross inoculation studies with the P. palmivora isolates from different hosts yielded successful results. This indicated that arecanut, rubber, cocoa, coconut and cardamom can serve as collateral hosts of P. palmivora infecting pepper. The sporangia produced by the P. palmivora isolates on cross inoculation showed considerable variations in their size and in few cases shape. These variations made identification directly from the host misleading.