There are three methods involved in biological control of weeds. These are;
Classical /introduction/inoculated biological control
Augmentation biological control /Inundative releases of predators
Integrated Pest Management /conservation biological control
Classical biological control is the initial introduction of relatively small number of exotic control agent. These agents feed on weeds directly multiplies there and suppress the population of weeds. The agents used are pathogen and arthropods of which insects are of vital importance e.g. Spurge beetle feeds on leafy spurge root. Classical control is widely used than that of augmentation and conservation method. The development of weeds that are resistant to biological and chemical control can be slowed down by using conservation method. Augmentation biological control (also termed as Bio-herbicide/ Mycoherbicide approach) is a method to control the weeds; the pathogen is applied in a way similar to that of herbicides.
They are applied to the foliage of leaves as aqueous spray. Collego (applied to control Northern jointvetch, weed of rice and soybean) and Devine (used against Honeyvine milk weed) are the two successful mycoherbicides.
Following are the steps taken for the management of weed by biological control; 1-over seases exploration 2-the target weed is identified to consider whether it is a good candidate for biological control or not 3-Selection and testing of biotic agents 4-Host spesifity test 5- Mass rearing and release 6-Monitoring release site 7- Redistribution 8-Maintaining control agent population 9-Evaluation.
Verified and Reviewed by Mansoor Javaid, Department of Agronomy, University College of Agriculture, University of Sargodha. The authors can be reached at <sumerasaleem401@yahoo.com>