Physiological Studies on Colletotrichum Gloeosporiodes Associated With Wither Tip Disease of Citrus and Its Chemical Control

Citrus is the second largest fruit producedinthe world and Pakistan is among the 12 large producers of the citrus fruit. It is grown in tropical and subtropical climate all over the world. Besides its high economical & nutritional values citrus is attacked by different pathogen such as fungi, bacteria, viruses and nematodes. Among all the pathogens Colletotrichumgloeosporiodescausing citrus wither tip disease is one of the major constrain in citrus production. Therefore current study was conducted to investigate the different physiological characters on the mycelial growth of C. gloeosporiodesand its chemical control. Among different fungal nutrient media Potato Dextrose Agar (PDA) gave maximum mycelial growth (7.9 cm) followed by Citrus leaf extract Agar (CLEA) (4.7 cm) and corn meal Agar (CMA) (3.3 cm).Temperature of 30°C favored maximum colony growth (8 cm) followed by 25°C (7.4 cm), 35°C (4.2 cm), 20°C (3.5 cm) and 15°C (2.3cm).A pH level of 6 favored maximum colony growth (7.9 cm) followed by 5 (7.5 cm), 4.5 (5.3cm), 4 (4.8 cm), 7(3.3cm) and 3(2.4 cm).Among the application of different fungicides such as Topsin-M, Copper oxychloride and Aliette at different concentration (300, 600 and 900 ppm). Topsin-M gave maximum result to inhibit the Maximum mycelial growth inhibition of C. gloeosporioides(1.1 cm) was produced by Topsin-M 9 days after incubation at 30 °C as compared to control (7.6 cm).