Study Material For Agriculture and allied Sectors

Plant Pathology  or  phytopathology  is  a  branch  of  agricultural,  botanical  or biological  science  which  deals  with cause,  etiology,  losses  and  control  of plant diseases.  Disease  is  a  malfunctioning  process  caused  by  continuous  irritation.  A plant  is  said  to  be  diseased  when  one  or  more  of  its  functions  are  interfered  by pathogen.  The  pathogen  is  any  agent  that  causes  pathos  (ailment / suffering)  or damage.  It  include  all  living  organisms  associated  with  causation  of  diseases, viruses  as  well  as  abiotic  agents  such  as  adverse  atmospheric  or  soil conditions. However,  the  term  is  generally  used  to  denote  living  organisms  (fungi, bacteria, mycoplasma  like  organisms,  nematodes  etc.)  and  viruses  but  not  abiotic causes. Pathogenicity is the ability of a pathogen to cause disease and pathogenesis is the chain of events that leads to the development of disease in plants. Recognition between host and pat

INFLORESCENCE 1. Racemose : Inflorescence with monopodoal branching i.e., the inflorescence axis continues to grow and gives off lateral and axillary flowers. (i) Raceme: Racemose inflorescence having a common axis and stalked flowers arranged in acropetal succession, e.g., Brassica. (ii) Panicle: Axis of raceme is branched. (iii) Spike: Inflorescence is similar to raceme but the flowers are sessile: e.g., Achyranthes aspera. (iv) Spikelet: Very small spike of a compound spike forming a unit; e.g., grasses. (v) Catkin (or Ament) : A pendulous spike or spike-like inflorescence consisting of small unisexual flowers ; e.g., Morus alba. (vi) Spadix : A spike with thick and fleshy axis covered by a large spathe ; e.g., Maize. (vii) Corymb : It is a modified raceme with relatively a short main axis, in which the lower flowers have much elongated pedicels so that the flowers come to the same level ; e.g., Candytuft. (viii) Umbel : It is a modified raceme, in which the flowers have