**2. Biotic factors (biotic stress)**

Biotic factors comprise chiefly insect pests and pathogens that are mainly responsible for reduction of cotton yield [14, 16, 17]; generally accounting the production losses of cotton yield due to insect pests around 84% [17] while for diseases and pathogens up to 30% [14]. The main biotic factors that leads to biotic stress for cotton field include insect pests (chewing and sucking pests) and some pathogens (viruses, bacteria and fungi) and weeds. While at the same time the abiotic factors particularly affect the occurrence of these pests and diseases [18]. Consequently, this situation is accountable for the emergence and incidence of the new pests and pathogens. Coupled with this we are viewing the main biotic factors, their key characteristics and incidence mechanisms and damage modes.

#### **2.1 Categorization of major pests and pathogens of cotton crop**

#### *2.1.1 Insect pests*

In the world over thirteen hundred and twenty six type of pests that mainly insects found as basis of infestation in cotton [19], whereas 162 different types of
