~ 442 ~ Journal of Entomology and Zoology Studies 2017; 5(1): 442-445 E-ISSN: 2320-7078 P-ISSN: 2349-6800 JEZS 2017; 5(1): 442-445 © 2017 JEZS Received: 03-11-2016 Accepted: 04-12-2016 Abdul Khaliq Department of Plant Pathology, the University of Agriculture, Peshawar Hakim Khan Department of Plant Pathology, the University of Agriculture, Peshawar Maria Department of Plant Pathology, the University of Agriculture, Peshawar Naseem Khan Department of Soil and Environmental Sciences, The University of Agriculture, Peshawar Laiq Zada Department of Soil and Environmental Sciences, The University of Agriculture, Peshawar Murad Ali Cereal Crops Research Institute Pirsabak Nowshera, Pakistan Muhammad Zahoor Department of Soil and Environmental Sciences, The University of Agriculture, Peshawar Samiullah Department of Soil and Environmental Sciences, The University of Agriculture, Peshawar Correspondence Abdul Khaliq Department of Plant Pathology, The University of Agriculture, Peshawar In vitro efficacy of Trichoderma harzianum Rifai against various isolates of Alternaria sp Abdul Khaliq, Hakim Khan, Maria, Naseem Khan, Laiq Zada, Murad Ali, Muhammad Zahoor and Samiullah Abstract An in vitro study was conducted to determine the efficacy of Trichoderma harzianum against ten isolates of Alternaria sp, the cause of leaf spot of bitter gourd. Isolates were collected from Peshawar (Chamkani, Nasirpur, Taimulpora, Yaseen Abad and Budhni) and Nowshera (Jabba Daudzai, Zakhi Miana, Ghari Momin, Tarujaba and Qasim Ali Baig) districts during 2011 growing season of the crop. All the ten isolates were cultured in aseptic conditions. Then, an experiment was conducted using Completely Randomized (CR) design. Each isolate was replicated three times. Significant differences (P<0.05) were observed in colony diameter of Alternaria isolates after four and eight days of incubation against T. harzianum. Trichoderma harzianum reduced the mycelia growth of Alternaria isolates by 70.4 to 88.1%, with lowest (70.4%) of Jabba Daudzai and highest (88.1%) of Chamkani as compared with their respective control, when T. harzianum was applied from two sides. It was 76.0 to 92.3% with lowest (76.0%) in Jabba Daudzai and highest (92.3%) of Chamkani, when T. harzianum was applied from four sides to the pathogens as compared to respective control. Keywords: In vitro, biological control, Trichoderma harzianum, Alternaria sp, bitter gourd 1. Introduction Bitter gourd (Momordica charantia L) belongs to family Cucurbitaceae. It is widely grown in India, Nepal and parts of the Indian sub-continent. It is an excellent source of vitamin A, B, C, E, and K, carbohydrates, phosphorus, Ca, Fe, Mg and Na. [1] . It has some medicinal values i.e useful for diabetic patients, stimulate digestion, have anti-malarial activity and effective for HIV infection [1, 9, 17] . Momordica charantia L is attacked by a number of diseases e.g leaf spots (Alternaria spp, Cercospora spp Myrothecium roridum) powdery mildew, white rot of fruit and Rhizoctonia solani fruit rot [13, 15] . Alternaria leaf spot has become a major threat to bitter ground in Khyber Pakhtunkhwa. The pathogen Alternaria sp cause great losses to the crop ranging from 80-88% on pumpkins and water melons in India [4] . The responsible fungus is Alternaria cucumerina (Elis and Everth) Elliot [6, 11] . The other crops infected by the pathogen are water melons, musk melons, pumpkins and cantaloupes [4, 5, 12, 14, 19-22] . Under local conditions, introduction of a large number of hybrid, bitter gourd in to the Pakistani cultivars, demonstrated the presence of high incidence of the disease. The environmental conditions especially temperatures (20-32) prevailing during the growing season and high relative humidity or dew presence favors the disease development [3] . Because of the importance of the crop and the disease (leaf spot of bitter gourd), this research study was proposed having the objectives as, (i) Isolation and identification of Alternaria sp from infected bitter gourd leaves collected from ten different locations of Peshawar and Nowshera and (ii) To test the efficacy of Trichoderma harzianum against ten different isolates of Alternaria sp. 2. Materials and Methods 2.1 Isolation of the pathogen Isolates (10) of leaf spot of bitter gourd (Alternaria sp) were collected from Peshawar (Chamkani, Nasirpur, Taimalpura, Yaseen Abad, and Budhni) and Nowshera (Jabba Daudzai, Zakhi Miana, Garhi Momin, Tarujabba and Qasim Ali Baig) districts during 2011 growing season of the crop. Pathogen from all the ten isolates was isolated on general medium, potato dextrose agar (PDA) medium under aseptic conditions. PDA was prepared by using the