INFESTATION OF Helicoverpa armigera Hübner ( Noctuidae : Lepidoptera ) ON SOYBEAN CULTIVARS IN POTHWAR REGION AND RELATIONSHIP WITH PHYSICO-MORPHIC CHARACTERS

Soybean (Glycine max L.) is one of the important legume crops of the world. It is believed to be among the oldest cultivated plants by man. It was originated from East Asia specifically from North China but now this crop is adapted to tropical, subtropical and temperate areas of the world, and it can be grown in spring and summer seasons. Major producers of soybean in the world are United States, Brazil, Argentina, China, India, Paraguay and Canada. It is an important source of fats, minerals, proteins, vitamins and energy for human and livestock. Its seeds contain 40-42% protein and 18-22% oil, based on its genetic and environmental aspects (Karishnan, 2000). It can provide 60% vegetable protein and 30% edible oil. Its waste products are used as a fodder for domestic animals (Ali, 2010). Pakistan is one of the largest importers of soy meal and soybean oil from Argentina and USA for the growth of its poultry and livestock industry. Pakistan has imported about 2.2 million metric tons of soybeans in 2016-2017 (GOP, 2017). The profitable production of soybean is affected by many biotic and abiotic factors. Among biotic factors diseases (Hussain et al., 2016; Ashfaq et al., 2017; Aslam et al., 2017a,b, 2018; Fateh et al., 2017; Kayani and Mukhtar, 2018; Kayani et al., 2017, 2018; Khan et al., 2017; Mukhtar, 2018; Mukhtar et al., 2017a,b, 2018; Tariq-Khan et al., 2017) and particularly the insect pests (Iftikhar et al., 2018; Javed et al., 2017a,b; Kassi et al., 2018; Nabeel et al., 2018) have been reported to cause reduction in yield. Losses in soybean production may reach up to 15-20% every year by the attack of insect pests only (Biswas, 2008). Among insect pests, the cotton bollworm, Helicoverpa armigera, is a destructive polyphagous pest causing severe damage to soybean in the world (Reddy et al., 2004). It feeds on different plant parts at different stages (Garcia, 2006). The pest is mainly controlled by chemicals and their use has caused several issues (Kranthi et al., 2002). Therefore, alternative strategies like cultural practices (fallow, crop rotation, ploughing, removing crop residues, planting time etc), crop hygiene, use of resistant varieties, biological control and sex pheromone etc are advocated (Rahoo et al., 2017, 2018a,b,c). However, the most productive and cheapest way to manage H. armigera is the use of resistant cultivars. The implementation of host plant resistance (HPR) Pak. J. Agri. Sci., Vol. 56(2),401-405; 2019 ISSN (Print) 0552-9034, ISSN (Online) 2076-0906 DOI: 10.21162/PAKJAS/19.6979 http://www.pakjas.com.pk