Abstract
Xamihomemal campestris pv. marivacearzim (Smith.) Dye inocula-ted on single or both cotyledonary leaves of cotton cultivar II- 557 produced water soaking and necrosis of the inoculated leaves and subsequent secondary leaves of the same plant, thus indicating the systemic nature of the disease. Plant height, stem dry weight, area and dry weight of leaves and total dry weight of inoculated plants were reduced significantly than noninoeulated plants. Leaf expan. sion was affected more than dry matter accumulation in most of the treatments.
INTRODUCTION
Cotton (Gossypium hintiturn L.) is an important cash crop of Pakistan but its average yield is only 1350 kg/ha. One of the important factors contributing towards its low yield is the attack of insect pests and diseases, which affect both the qtbality as well as quantity of the produce. Amongst various disuses, bacterial blight caused by licinthonionfis campe.cfris pv. rnaivarearum recorded rear Multan in 1965 is responsible for heavy losses to cotton crop (Evans, 1976). According to Hussain and Ali (1975) this disease can reduce the yield of the crop upto 50 per cent under favourable conditions of the disease development, The effect of the pathogen on different growth parameter. of the host 'ai still unknown which was studied and is presented here. MATERIALS AND METHODS Acid deliuted seeds of cotton cultivar II-557 were sown in 2 cm diameter clay pots 10 seeds in each pot. When the cotton EeedIings !Haired the height of about 10 cm, crop was thinned to two plants per pot. A highly pathogenic culture of X, oac ptstris pv. maivatearittri was is from the infected cotton plant and was identified by morphlogical, biochemical characters nod 7,suat pathogenicity tests.
